BEGIN:VCALENDAR VERSION:2.0 PRODID:talks.ox.ac.uk BEGIN:VEVENT SUMMARY:Lovanov-Rostovsky Lecture 2026: It's All About Oxygen - Professor Donald E. Canfield FRS (University of Southern Denmark) DTSTART;VALUE=DATE-TIME:20260313T120000Z DTEND;VALUE=DATE-TIME:20260313T130000Z UID:https://talks.ox.ac.uk/talks/id/1fdfc499-6d6e-4b43-98d5-76f0570a5dc2/ DESCRIPTION:We live in a well oxygenated planet\, but it has not always be en this way. In this talk I will outline the history of the oxygenation of Earth\, outlining some of the tools that we use to understand this histor y. I will explore how oxygenation has both impacted and been impacted by b iological evolution. I will also explore how the history of earth oxygenat ion may have regulated timing of major biological innovations like the evo lution of algae and the evolution of animals.\n\n \nSpeakers:\nProfessor D onald E. Canfield FRS (University of Southern Denmark) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/1fdfc499-6d6e-4b43-98d5-76f0570a5dc2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Lovanov-Rostovsky Lecture 2026: It's All About Oxygen - P rofessor Donald E. Canfield FRS (University of Southern Denmark) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:From mixed signals to magmatic systems: satellite measurements of volcanism - Dr Susanna Ebmeier (University of Leeds) DTSTART;VALUE=DATE-TIME:20260220T120000Z DTEND;VALUE=DATE-TIME:20260220T130000Z UID:https://talks.ox.ac.uk/talks/id/15401cef-53ca-40ab-beab-9375d47fdc04/ DESCRIPTION:Satellite imagery provides a unique window into volcano and ma gmatic processes\, providing potentially global measurements of deformatio n\, degassing and thermal emissions. These measurements illuminate stages of magmatism spanning from pluton growth\, to landscape formation to the environmental impact of volcanic eruptions. Satellite radar measurements\ , in particular\, capture processes associated with the movement of magma in the Earth’s crust and can play a role in forecasting the development of unrest and duration of eruptions. I will discuss efforts to automate p rocessing and analysis\, required by the recent order of magnitude increas e in freely available\, systematically acquired satellite imagery. This in volves the application of signal processing methods such as source separat ion and unsupervised classification\, and is also a powerful tool for dist inguishing between superimposed geophysical processes. My research focuse s on how to extract volcanologically useful parameters from satellite imag ery\, and I will present case studies of effusion rate estimation\, charac terisation of eruption volume from vegetation impacts and the impact of rh eology on displacements.\nSpeakers:\nDr Susanna Ebmeier (University of Lee ds) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/15401cef-53ca-40ab-beab-9375d47fdc04/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:From mixed signals to magmatic systems: satellite measure ments of volcanism - Dr Susanna Ebmeier (University of Leeds) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The big melt: small cells big consequences - Prof. Liane G. Bennin g (GFZ Helmholtz Centre for Geosciences) DTSTART;VALUE=DATE-TIME:20260213T120000Z DTEND;VALUE=DATE-TIME:20260213T130000Z UID:https://talks.ox.ac.uk/talks/id/ae1e322e-b0ac-4a6f-9f55-1bd70a5d2bec/ DESCRIPTION:Climate change enhanced melting of the Greenland Ice Sheet has long passed the 1.5˚ C threshold resulting in dramatic melt rates and a large contribution to global sea level rise. Pigmented algae that bloom on snow and ice surfaces as well as dark cryoconite materials exacerbate thi s melting as they reduce albedo locally by up to 25 %. The algae blooms th emselves are fuelled by nutrients\, which they derive from melting snow an d ice and mineral dust. Such molecular scale mineral – microbe interacti ons play a fundamental role in the landscape-wide processes that shape our planet now and in a warmer future. Blooms are triggered annually through the tight interplay between geochemical\, mineralogica\, microbiological a nd physical processes that we slowly start to unravel. Combining detailed analyses of inorganic and organic components in snow and ice surface measu rements with drone and satellite data we can now determine the role that m icrobes and minerals play in shaping landscape scale processes on Greenlan d and this helps parameterise global melt and sea level rise model predict ions.\nSpeakers:\nProf. Liane G. Benning (GFZ Helmholtz Centre for Geoscie nces) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/ae1e322e-b0ac-4a6f-9f55-1bd70a5d2bec/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The big melt: small cells big consequences - Prof. Liane G. Benning (GFZ Helmholtz Centre for Geosciences) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The Pursuit of Weakness: Feedbacks between metamorphism\, mass tra nsfer\, and mechanics during subduction initiation - Dr Alissa J. Kotowsk i (Utrecht University) DTSTART;VALUE=DATE-TIME:20260123T120000Z DTEND;VALUE=DATE-TIME:20260123T130000Z UID:https://talks.ox.ac.uk/talks/id/5b7637db-42d6-46fb-92e9-191a1c75bceb/ DESCRIPTION:Earth’s plate tectonic regime is driven by subduction\, but how do brand new subduction zones initiate in the first place? To get one plate to sink beneath another\, deformation has to localize: rigid oceanic plates must weaken along a narrow plate interface. Localization involves feedbacks between temperature\, fluid/mass transfer\, metamorphism\, and r heology\, but these feedbacks are difficult to study directly because in-p rogress subduction initiation is rare on Earth today. My approach is to us e geologic records preserved in large-slab ophiolites (e.g.\, Oman\, Newfo undland\, New Caledonia etc.). Ophiolites commonly form in proto-forearc s ettings and therefore provide the upper plate’s perspective. Where they are well-preserved\, ophiolites also contain remnants of the down-going pl ate: hundreds-of-meters thick ductile shear zones made of metamorphosed oc eanic crust (± sediments) accreted beneath the ophiolite mantle—metamor phic soles. Soles are dynamic archives of how heat\, fluids\, reactions an d deformation interacted as the plate interface was born. In this talk\, I use the Ordovician Mont Albert Ophiolite (Gaspé Peninsula\, Québec\, Ca nada) and it’s remarkably exposed metamorphic sole to test two commonly- cited mechanisms for lithosphere-scale strain localization: (1) serpentini zation and (2) partial melting. I will argue that—at least for Mont Albe rt—neither mechanism explains the observations\, and therefore did not s ubstantially localize strain. The payoff\, however\, is that investigating each of these ideas showcases the power of integrating field structures\, geochemistry\, and electron microscopy. This approach illuminates yet les s-appreciated feedbacks between temperature evolution\, mass transfer\, an d strength that do promote weakening. I’ll close by speculating how less ons from “well-preserved” Phanerozoic soles may shed new light on how subduction may have initiated on a hotter\, more primitive Earth. \nSpeake rs:\nDr Alissa J. Kotowski (Utrecht University) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/5b7637db-42d6-46fb-92e9-191a1c75bceb/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The Pursuit of Weakness: Feedbacks between metamorphism\, mass transfer\, and mechanics during subduction initiation - Dr Alissa J . Kotowski (Utrecht University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Chemical Evolution of Sea Water: From the Archean to the Modern Er a via the Great Oxidation Event - Prof Francis Albarède (Ecole Normale Su perieure de Lyon) DTSTART;VALUE=DATE-TIME:20260116T120000Z DTEND;VALUE=DATE-TIME:20260116T130000Z UID:https://talks.ox.ac.uk/talks/id/d795d478-dc01-4f58-a5ce-d2d4b58e9da9/ DESCRIPTION:The chemical composition of seawater has changed profoundly ov er Earth’s history\, reflecting the combined influence of tectonics\, co ntinental growth\, ocean–crust interaction\, and biological evolution. I n the Archean\, when continents were small and atmospheric oxygen was low\ , limited continental weathering resulted in low oceanic alkalinity and re stricted carbonate formation. At the same time\, seawater chemistry was sh aped by two external controls: continental runoff\, which set the long-ter m chlorinity and salinity budget of the ocean\, and hydrothermal interacti on with the oceanic crust\, which modified non-conservative ions and alkal inity. Under these conditions\, phosphorus availability in the pre–Great Oxidation Event ocean was likely limited\, owing to weak continental inpu ts and efficient scavenging of phosphate by iron oxides in ferruginous wat ers. The progressive emergence of continents increased the delivery of alk alinity and nutrients\, weakened iron–phosphate coupling\, and supported higher marine productivity\, contributing to the rise of atmospheric oxyg en. Today\, the ocean continues to play a central role in the carbon cycle \, with physical circulation controlling short-term CO₂ uptake and biolo gical processes governing long-term carbon storage. The modern ocean opera tes as a chemically buffered reactor in which alkalinity\, redox state\, n utrients\, and circulation jointly control carbon storage through physical and biological pumps. This seminar explores how the coevolution of ocean chemistry\, continental growth\, and nutrient cycling has regulated Earth ’s climate and habitability through deep time.\nSpeakers:\nProf Francis Albarède (Ecole Normale Superieure de Lyon) LOCATION:Department of Earth Sciences (Conference room\, 50.11)\, South Pa rks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/d795d478-dc01-4f58-a5ce-d2d4b58e9da9/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Chemical Evolution of Sea Water: From the Archean to the Modern Era via the Great Oxidation Event - Prof Francis Albarède (Ecole N ormale Superieure de Lyon) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth: An Eyewitness to Planetary Habitability - Prof Dr Trond Tor svik (University of Oslo) DTSTART;VALUE=DATE-TIME:20260227T120000Z DTEND;VALUE=DATE-TIME:20260227T130000Z UID:https://talks.ox.ac.uk/talks/id/2dc087b4-3924-4d0a-8859-6b9037fbf58f/ DESCRIPTION:\nAbstract\n\nThe idea that worlds around other stars could de velop and maintain environments hospitable to life\, in a way like our pla net\, has captivated scientists for centuries. Yet\, to investigate this q uestion\, we must recognize and characterize the key conditions that make a planet habitable. Earth ― the only planet on which life is known to ha ve originated ― is unique in many ways\, including the presence of abund ant surface water\, a large moon\, a long-lived magnetic field\, and plate tectonics. Yet\, which of these and other characteristics are essential f or its long-term habitability?\n\nA major challenge is that habitability f actors vary because they are time-dependent due to changes in the Sun’s energy and our planet’s chemical\, thermal and (thereby) physical and te ctonic evolution. Plate tectonics regulates interior temperatures\, atmosp heric greenhouse gas concentrations and surface temperatures. Subduction e nables recycling of volatile elements between the surface and the mantle a nd is probably essential for sustaining planetary habitability. Because th e questions of when\, why and how plate tectonics started are debated\, an improved understanding of Earth’s evolution is critically needed.\n\nIt is not necessarily obvious that key habitability factors such as plate te ctonics will persist once started\, a dynamo-driven magnetic field can sto p and perhaps re-emerge later through inner-core nucleation\, and the Eart h’s axial tilt may also become unstable as the Moon is moving away. Ulti mately\, all planets lose their habitability\, and in about two billion ye ars when the Sun’s energy has increased by 15%\, Earth will enter a mois t greenhouse\, followed by runaway evaporation of the oceans. An in-depth knowledge of Earth-like habitability\, and how our planet sustained condit ions for life’s evolution over geological timescales\, is critical for i dentifying habitable planets orbiting other stars that potentially are\, o r have been\, habitable around other stars.\n\nSpeakers:\nProf Dr Trond To rsvik (University of Oslo) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/2dc087b4-3924-4d0a-8859-6b9037fbf58f/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth: An Eyewitness to Planetary Habitability - Prof Dr Trond Torsvik (University of Oslo) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The influence of low-spin ferrous iron on the oxidation state of t he Earth's mantle - Prof. Dr. Paolo Angelo Sossi (ETH Zürich) DTSTART;VALUE=DATE-TIME:20260206T120000Z DTEND;VALUE=DATE-TIME:20260206T130000Z UID:https://talks.ox.ac.uk/talks/id/e7b3837c-3866-45d9-b5f4-552977fbd759/ DESCRIPTION:The Earth's mantle has elevated Fe3+ contents relative to thos e of other telluric bodies\, a property thought to reflect the disproporti onation of ferrous iron into its metallic and ferric counterparts during c ore formation. However\, how the oxidation and electronic state of iron ch ange as a function of pressure in compositions relevant to that of Earth's mantle are not fully understood. In this study\, we present in-situ energ y domain synchrotron Mössbauer spectra of 57Fe-enriched peridotitic- and basaltic glasses at 298 K compressed from 1 bar to 174 GPa in a diamond an vil cell. Glasses were synthesised with different Fe3+/[Fe3+ + Fe2+] ratio s\, 0.02 ± 0.02 and 1.00 ± 0.02\, respectively\, as determined by colori metry. At 1 bar\, the spectrum of the Fe3+-basaltic glass is well fit by a single doublet. In contrast\, the spectra of both Fe2+-rich peridotitic a nd basaltic glass are fit by two doublets\, D1 (~92 %) and D2 (~8 %) at 1 bar. As pressure increases\, the integral area of the D2 doublet increases at the expense of D1 to reach a D2/(D1 + D2) ratio of 0.65 by 172 GPa. Be cause this transition is reversible with pressure and no metallic iron is detected\, the D2 feature is ascribed to Fe2+ in its low spin (LS) state\, whereas D1 is consistent with Fe2+ high spin (HS). This assignment resolv es a long-standing controversy on the interpretation of the Mössbauer spe ctra of basaltic glasses. As a consequence of the stabilisation of Fe2+ wi th pressure\, terrestrial planets more massive than Earth likely do not ho st increasingly oxidising mantles.\nSpeakers:\nProf. Dr. Paolo Angelo Soss i (ETH Zürich) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/e7b3837c-3866-45d9-b5f4-552977fbd759/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The influence of low-spin ferrous iron on the oxidation s tate of the Earth's mantle - Prof. Dr. Paolo Angelo Sossi (ETH Zürich) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Ridge flank hydrothermal contributions to global biogeochemical cy cles and archives of changing global conditions: Insights from the IODP So uth Atlantic Transect - Dr Rosalind Coggon (University of Southampton) DTSTART;VALUE=DATE-TIME:20260306T120000Z DTEND;VALUE=DATE-TIME:20260306T130000Z UID:https://talks.ox.ac.uk/talks/id/19769ade-e33e-4e52-a60e-74c0890ac53d/ DESCRIPTION:Throughout its life the ocean crust is a key boundary between Earth’s interior and the oceans/atmosphere. Hydrothermal circulation of seawater-derived fluids through the cooling and aging crust results in che mical exchange between Earth’s interior and oceans and atmosphere\, play ing an important role in long-term biogeochemical cycles. Altered ocean cr ust provides a time-integrated record of its geochemical exchange with sea water. Furthermore\, hydrothermal minerals formed from ridge flank fluids record the evolving chemistry of the overlying oceans – itself an integr ator of a range of Earth processes. I will present an overview of how scie ntific ocean drilling experiments across ridge flanks contribute to our un derstanding of the processes that control ridge flank hydrothermal exchang es\, the role these exchanges play in global geochemical cycles\, and the extent to which they record and respond to wider changes in the Earth syst em. In particular\, the South Atlantic Transect (IODP Expeditions 390/393) \, designed to recover the upper crust and overlying sediments across the western flank of the slow-spreading Mid-Atlantic Ridge to investigate hydr othermal aging and microbiological evolution of the ocean crust\, and the paleoceanographic evolution of the overlying South Atlantic. \nSpeakers:\n Dr Rosalind Coggon (University of Southampton) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/19769ade-e33e-4e52-a60e-74c0890ac53d/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Ridge flank hydrothermal contributions to global biogeoch emical cycles and archives of changing global conditions: Insights from th e IODP South Atlantic Transect - Dr Rosalind Coggon (University of Southam pton) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth's Climate as an Evolutionary Agent: Quantifying Temperature Change Across Major Diversification Events - Dr Kristin Bergmann (MIT) DTSTART;VALUE=DATE-TIME:20251205T120000Z DTEND;VALUE=DATE-TIME:20251205T130000Z UID:https://talks.ox.ac.uk/talks/id/3ebabbd0-80d8-43a9-9844-f6a8a30ea1e2/ DESCRIPTION:This talk places new constraints on ocean temperature change a cross the Neoproterozoic to Phanerozoic transition\, when the fossil recor d documents some of the most dramatic changes in the history of complex li fe. Traditional δ18O data blur temperature with changes in seawater compo sition\; clumped isotopes break that ambiguity. Using stratigraphically an chored\, fabric-targeted sampling\, we reconstruct nearshore seawater temp eratures and\, where possible\, infer ice volume from seawater δ18O.\n\nR esults reveal large\, directional climate shifts with ecological consequen ces. In the Tonian and Cryogenian\, clumped-isotope data from Oman and els ewhere indicate near-modern tropical temperatures before and after Snowbal l Earth glaciations\, suggesting dynamic hydrologic and climatic transitio ns. During the Ediacaran\, post-glacial warming followed by ≥20 °C cool ing likely expanded oxygenated habitats and set the stage for early animal diversification. In the Ordovician\, ~15 °C of long-term tropical coolin g over ~40 Myr culminated in brief but extensive glaciation\, providing th e climate context for the Great Ordovician Biodiversification Event.\n\nBy pairing clumped-isotope temperatures with age control and complementary p roxies\, we build a quantitative framework linking climate and habitabilit y\, showing how temperature change guided life’s evolutionary trajectory through deep time.\nSpeakers:\nDr Kristin Bergmann (MIT) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/3ebabbd0-80d8-43a9-9844-f6a8a30ea1e2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth's Climate as an Evolutionary Agent: Quantifying Tem perature Change Across Major Diversification Events - Dr Kristin Bergmann (MIT) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Seismic Imaging and monitoring in Iceland: ongoing eruption sites and unexplored areas - Dr Jenny Jenkins (Durham) DTSTART;VALUE=DATE-TIME:20251128T120000Z DTEND;VALUE=DATE-TIME:20251128T130000Z UID:https://talks.ox.ac.uk/talks/id/fe6685df-b7db-40cf-b908-aec7ae5500c4/ DESCRIPTION:This talk will focus on two seismic projects in Iceland: \n\n The Reykjanes Peninsula in SW Iceland is currently an area of great intere st\, both due to the long-term exploitation of geothermal systems used for energy generation and since an ongoing series of volcanic eruptions began there in 2021. Accordingly\, it is heavily instrumented with seismic moni toring stations run by numerous international groups. Bringing together da ta from both current and historic seismic data\, we generate updated image s of deep crustal and upper most mantle structure down to 40km\, providing large-scale tectonic context for the ongoing volcanic unrest.\n\nUnlike t he rest of Iceland the remote central Icelandic highlands have previously had little-to no seismic monitoring\, despite the presence of two major ac tive volcanic systems. Here we present the first results from a Durham run network of 15 broadband instruments that provide insight into detailed mi cro-seismicity in this never-before studied region. Results reveal exponen tially increasing rates of micro-seismicity beneath Hofsjökull (Iceland ’s largest active volcano by area)\, including tantalising suggestions o f deep low-frequency events that may indicate magma movement at depth.\nSp eakers:\nDr Jenny Jenkins (Durham) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/fe6685df-b7db-40cf-b908-aec7ae5500c4/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Seismic Imaging and monitoring in Iceland: ongoing erupt ion sites and unexplored areas - Dr Jenny Jenkins (Durham) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Resolving the Ediacaran enigma - Dr Frankie Dunn (OUMNH) DTSTART;VALUE=DATE-TIME:20251121T120000Z DTEND;VALUE=DATE-TIME:20251121T130000Z UID:https://talks.ox.ac.uk/talks/id/ae23abcf-9cbd-4b5c-8464-4230b089a3cd/ DESCRIPTION:The radiation of animals across the Ediacaran-Cambrian transit ion is one of the most transformational events in Earth history\, radicall y changing Earth’s surface environments. However\, while fossils from th e Cambrian are readily recognised as belonging to extant groups\, those fr om the late Ediacaran Period show distinctive forms with no counterparts a mong living species. Although these Ediacaran fossils are often held to re present the antecedents to modern animal groups\, their strange anatomies have meant that\, for the most part\, they have been eschewed from the deb ate and their unique insight left unrealised. My work combines novel morph ogenetic data and phylogenetic systematic studies to show that these uniqu e fossils are animals to the exclusion of alternatives and likely occupy a critical position in the tree of animal life. This conclusion enables me to integrate Ediacaran macrofossils into debates concerning the ancestors of major animal lineages and the mode of early animal evolution\, for exam ple\, in the influence of the evolving regulatory genome on the evolution of animal complexity.\nSpeakers:\nDr Frankie Dunn (OUMNH) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/ae23abcf-9cbd-4b5c-8464-4230b089a3cd/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Resolving the Ediacaran enigma - Dr Frankie Dunn (OUMNH) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth’s Early Oxygenation: A story of Feast and Famine - Prof Ku rt Konhauser (University of Alberta) DTSTART;VALUE=DATE-TIME:20251114T120000Z DTEND;VALUE=DATE-TIME:20251114T130000Z UID:https://talks.ox.ac.uk/talks/id/b128bca1-7757-4bba-bb2f-a32293c0eaa6/ DESCRIPTION:The more we learn about Earth and life\, the clearer it become s that their mutual feedbacks\, not just their individual processes\, are the true drivers of change. Consider how microbial genetic innovations onc e triggered biological reactions that reshaped Earth’s surface. In turn\ , environmental shifts driven by tectonics or other geological processes c reated new ecological opportunities\, sometimes in entirely unexpected way s. The most striking example of this interplay is the coevolution of oxyge nic photosynthesis and Earth’s redox history. Ancient cyanobacteria evol ved the ability to split water\, releasing oxygen that accumulated in the atmosphere and oceans. Rising oxygen levels enabled the ozone layer to for m and aerobic respiration to emerge\, while continental growth and cooling enhanced oxidative weathering\, delivering trace nutrients that fueled pr imary production. Positive feedbacks reinforced oxygen release\, but negat ive ones—such as sulfate-driven anoxia stripping metals from seawater— constrained it. Thus\, life simultaneously drove and moderated atmospheric change\, with cyanobacteria both architects and casualties of their own s uccess. In this talk\, I will explore the main forces that shaped cyanobac terial evolution and\, by extension\, Earth’s oxygenation. Recent studie s reveal that the rise of oxygen was not a smooth\, monotonic climb\, but rather a dynamic and oscillatory process. Periods of oxygen abundance alte rnated with episodes of scarcity\, creating cycles of opportunity and stre ss for cyanobacteria and their microbial competitors\, including methanoge ns and photoferrotrophs. These ecological struggles and feedbacks not only determined who thrived\, but also left lasting imprints on the redox evol ution of our planet.\nSpeakers:\nProf Kurt Konhauser (University of Albert a) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/b128bca1-7757-4bba-bb2f-a32293c0eaa6/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth’s Early Oxygenation: A story of Feast and Famine - Prof Kurt Konhauser (University of Alberta) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:New Perspectives on the Formation and Evolution of Earth’s Solid Inner Core - Dr Alfred Wilson-Spenser (Leeds) DTSTART;VALUE=DATE-TIME:20251031T120000Z DTEND;VALUE=DATE-TIME:20251031T130000Z UID:https://talks.ox.ac.uk/talks/id/28dbca28-6ce2-467e-bb71-e5ae9851e0d4/ DESCRIPTION:he growth of Earth’s solid inner core from the liquid outer core is central to the dynamics of our planet’s deep interior. This grow th generates thermal and chemical buoyancy which is crucial for generating the geomagnetic field. However\, the classical view of how the inner core first formed does not consider the physical requirement that liquids must be supercooled below the melting point before freezing can begin. Mineral physics calculations have suggested that at least 450 K of supercooling is needed to spontaneously nucleate the inner core. However\, when satisf ying inferences from geophysical constraints\, the maximum available super cooling has been estimated at 420 K\, meaning that the origins of the in ner core are enigmatic. We explore the consequences of supercooling the Ea rth’s ancient liquid core on inner core formation\, growth and dynamics\ , and the interpretation of seismic and palaeomagnetic observations. Colle ctively\, these additional constraints suggest that the core was supercool ed less than 100 K at the time of inner core nucleation. Even with small s upercooling\, Earth’s core is required to have grown rapidly immediately after nucleation. Evidence for this rapid growth may exist in the palaeom agnetic record and seismological signatures of inner core structure.\nSpea kers:\nDr Alfred Wilson-Spenser (Leeds) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/28dbca28-6ce2-467e-bb71-e5ae9851e0d4/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:New Perspectives on the Formation and Evolution of Earth ’s Solid Inner Core - Dr Alfred Wilson-Spenser (Leeds) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Assessing resources for Geochemical Carbon Dioxide Removal - Prof Phil Renforth (Heriot-Watt) DTSTART;VALUE=DATE-TIME:20251107T120000Z DTEND;VALUE=DATE-TIME:20251107T130000Z UID:https://talks.ox.ac.uk/talks/id/5eb0a7cd-d3ed-4727-ad83-8133e8731dfc/ DESCRIPTION:Large-scale carbon dioxide removal (CDR) strategies are needed for us to reach our climate targets. Geochemical CDR involves approaches that react atmospheric CO2 with naturally occurring rocks or anthropogenic alkaline materials. Many of these technologies are currently being pilote d and tested commercially. However\, there has been no comprehensiveassess ment of the resources available for geochemical CDR. Understanding the spa tial distribution\, capacity\, and accessibility of these materials is ess ential for informing international climate policy\, guiding infrastructure investment\, and ensuring environmental safety. This presentation will su mmarise the current state of knowledge and demonstrate how gCDR resources are fundamental to technology deployment.\nSpeakers:\nProf Phil Renforth ( Heriot-Watt) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/5eb0a7cd-d3ed-4727-ad83-8133e8731dfc/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Assessing resources for Geochemical Carbon Dioxide Remova l - Prof Phil Renforth (Heriot-Watt) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Resolving the Boundary Layer Paradox: Seismic Clues to the Origin of Lithosphere Discontinuities - Dr Totulope Olugboji (University of Roche ster) DTSTART;VALUE=DATE-TIME:20250620T120000 DTEND;VALUE=DATE-TIME:20250620T130000 UID:https://talks.ox.ac.uk/talks/id/589a1b85-9db3-4ce7-a577-49f641efc6f1/ DESCRIPTION:\nSpeakers:\nDr Totulope Olugboji (University of Rochester) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/589a1b85-9db3-4ce7-a577-49f641efc6f1/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Resolving the Boundary Layer Paradox: Seismic Clues to th e Origin of Lithosphere Discontinuities - Dr Totulope Olugboji (University of Rochester) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Terrestrial carbon cycle feedbacks in a warmer world – new insig hts from ancient climates - Dr Gordon Inglis (Southampton) DTSTART;VALUE=DATE-TIME:20250613T120000 DTEND;VALUE=DATE-TIME:20250613T130000 UID:https://talks.ox.ac.uk/talks/id/32d95cc3-5503-48e9-b441-f66d29807f91/ DESCRIPTION:The magnitude of future warming is dependent upon carbon cycle feedbacks\, which can either amplify or mitigate warming. The latest gene ration of CMIP6 models suggest that the combined effects of known climate feedback mechanisms is to amplify global warming. However\, climate models are blind to the ‘unknown unknowns’ - these are the things we know li ttle about and have potential to take future climate into unimagined direc tions. Transient warming events in the geological record (hyperthermals) c apture the response of the Earth system to all the feedbacks in operation\ , including those that we are unaware of. In this talk\, I will use coasta l marine sediments deposited during the Paleocene-Eocene Thermal Maximum ( 56 million years ago) to reveal how the terrestrial carbon cycle operates in a warmer world. This talk will focus on two highly uncertain carbon cyc le feedbacks: (1) the erosion and burial of terrestrial organic carbon (a potential CO2 sink)\, and (2) the oxidation of rock organic carbon (a pote ntial CO2 source). I will show how organic geochemical techniques have the potential to illuminate these uncertain feedbacks during the PETM and oth er key climate events in Earth’s history.\nSpeakers:\nDr Gordon Inglis ( Southampton) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/32d95cc3-5503-48e9-b441-f66d29807f91/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Terrestrial carbon cycle feedbacks in a warmer world – new insights from ancient climates - Dr Gordon Inglis (Southampton) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Who gives a fuchsite about chromite? What chromite tells us about the evolution of Earth’s mantle and continents - Dr Pedro Waterton (Univ ersity of Copenhagen) DTSTART;VALUE=DATE-TIME:20250530T120000 DTEND;VALUE=DATE-TIME:20250530T130000 UID:https://talks.ox.ac.uk/talks/id/79b92bd2-f877-48c6-9690-e7a4ccd9eb77/ DESCRIPTION:Chromite is a ubiquitous early crystallising phase in mafic an d ultramafic magmas. It has long been used as a ‘petrogenetic indicator ’ in igneous and metamorphic rocks\, as its wide range of solid solution s reflect the composition of the magmas that chromite crystallised from. U nusually for a mafic mineral\, chromite is robust both during metamorphism and sedimentary transport\, and can retain primary information about its source rocks where no other primary mafic minerals are preserved. Chromite also strongly partitions platinum-group elements\, including osmium\, mak ing it suitable for study using the Re-Pt-Os isotope systems.\n\nIn this p resentation\, I document my descent into chromite research\, from a naïve interest in ultramafic lavas\, through investigations into the age and or igin of ultramafic bodies in Greenland\, to the broad scale evolution of t he Earth’s mantle and continental crust. I outline how the composition o f chromite varies during crystallisation of mafic and ultramafic melts\, a nd how chromite trace elements can help us narrow down the parental melt c omposition of intrusions. I discuss the use and abuse of the Re-Pt-Os syst ems to place ages on the formation of chromite and its host rocks. Finally \, I introduce fuchsitic quartzites\; rare\, predominantly Archaean metase dimentary rocks that contain abundant detrital chromite. I present ongoing work to develop the use of detrital chromite grains as a tool to understa nd the growth of continental crust\, and address the problem of Earth’s ‘missing’ mafic crustal record.\nSpeakers:\nDr Pedro Waterton (Univers ity of Copenhagen) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/79b92bd2-f877-48c6-9690-e7a4ccd9eb77/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Who gives a fuchsite about chromite? What chromite tells us about the evolution of Earth’s mantle and continents - Dr Pedro Water ton (University of Copenhagen) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Carbonatite-related mineral deposits - Prof John Mavrogenes (ANU ( Australian National University)) DTSTART;VALUE=DATE-TIME:20250523T120000 DTEND;VALUE=DATE-TIME:20250523T130000 UID:https://talks.ox.ac.uk/talks/id/21188f51-9f40-4b3b-9453-c83feb331a88/ DESCRIPTION:Carbonatites\, probably the strangest rocks on Earth\, are oft en associated with critical rare earth elements\, making them increasingly relevant to society. Such deposits are also often associated with enric hments in Nb\, Ba\, Zr\, Sr\, Ti and Cu\, as well as apatite and fluorite. Through observations of natural and experimental examples I will review o ur current understanding of how these intriguing enrichments might occur. Most of the key processes involved\, as summarised below (Yaxley et al\, 2 022)\, will be presented along with numerous real-world examples and rampa nt speculations.\nSpeakers:\nProf John Mavrogenes (ANU (Australian Nationa l University)) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/21188f51-9f40-4b3b-9453-c83feb331a88/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Carbonatite-related mineral deposits - Prof John Mavrogen es (ANU (Australian National University)) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Modelling mineral equilibria in igneous and metamorphic rocks: a n ew thermobarometric method and equations of state - Dr Eleanor Green (Univ ersity of Melbourne) DTSTART;VALUE=DATE-TIME:20250502T120000 DTEND;VALUE=DATE-TIME:20250502T130000 UID:https://talks.ox.ac.uk/talks/id/f82f15d6-ef1f-4e86-aa7d-f235576ce8a5/ DESCRIPTION:The modelling of rock systems in chemical equilibrium provides one of the few quantitative links between petrology and other geoscience disciplines. Mineral equilibrium modelling may be used to estimate the pre ssures and temperatures recorded in igneous or metamorphic rocks\, or to s imulate the mineralogical changes by which a rock responds to changes in p ressure\, temperature\, or bulk chemistry.\n\nIn this talk I will discuss some recent developments in mineral equilibrium modelling. AvPT+ is new me thod in geothermobarometry\, implemented in the software THERMOCALC\, whic h is in some sense a hybrid between two established methods: multiple-reac tion thermobarometry and pseudosection modelling. A comparison of results from avPT+ and pseudosection modelling suggests that “just one more gene ration” of mineral equations of state is needed\, reproducing observed m ineral compositions more faithfully than the current generation. I will di scuss the experiment-based approach that my research group is taking to th is task\, before outlining the fundamental experimental and modelling limi tations on mineral equilibrium calculations.\nSpeakers:\nDr Eleanor Green (University of Melbourne) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/f82f15d6-ef1f-4e86-aa7d-f235576ce8a5/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Modelling mineral equilibria in igneous and metamorphic r ocks: a new thermobarometric method and equations of state - Dr Eleanor Gr een (University of Melbourne) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Convection in Europa's ocean subject to tidal heating from the man tle - Dr Daphne Lemasquerier (St Andrews) DTSTART;VALUE=DATE-TIME:20250509T120000 DTEND;VALUE=DATE-TIME:20250509T130000 UID:https://talks.ox.ac.uk/talks/id/b15263f4-fa7e-4045-8572-06f9fa522218/ DESCRIPTION:Several icy moons of Jupiter and Saturn\, including Europa and Enceladus\, host liquid oceans buried beneath their icy crusts. Geologica l features of the ice crusts as well as large-scale variations of the ice thickness are often attributed to endogenic processes within the ice. Howe ver\, the ice crust is also coupled to the rocky interior via the convecti ve ocean which controls heat and material exchanges. Using direct numerica l simulations in rotating spherical shells\, we investigate how tidal heat ing within the silicate mantle could affect rotating thermal convection in Europa's ocean. In particular\, tidal heating in the rocky mantle is spat ially heterogeneous (larger at the poles\, with longitudinal variations of order 2 in the equatorial region). These horizontal variations can drive "thermal winds" which would significantly change the general circulation i n the ocean compared with homogeneous heating\, which is more representati ve of radiogenic heating. These results suggest that if tidal heating is d ominant in the silicate mantle\, its pattern could be partially transposed up to the ice despite the dynamic ocean lying between the ice crust and t he rocky mantle.\nSpeakers:\nDr Daphne Lemasquerier (St Andrews) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/b15263f4-fa7e-4045-8572-06f9fa522218/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Convection in Europa's ocean subject to tidal heating fro m the mantle - Dr Daphne Lemasquerier (St Andrews) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Self-organisation in mafic cumulates: differential migration of im miscible silicate liquids in the crystal mush - Prof Marian Holness (Cambr idge) DTSTART;VALUE=DATE-TIME:20250516T120000 DTEND;VALUE=DATE-TIME:20250516T130000 UID:https://talks.ox.ac.uk/talks/id/f0c7c04b-7938-48b7-8f4c-47b96b7f4b82/ DESCRIPTION:Self-organisation in plutonic igneous rocks has been suggested to form by a variety of mechanisms including oscillatory nucleation and g rowth\, competitive particle growth (CPG)\, recrystallisation during compa ction\, and by a reduction in the total grain boundary energy budget based on the assumption that the energy of boundaries between two grains of the same mineral is less than that between two grains of different minerals. These various mechanisms can be distinguished on the basis of their micros tructural signatures. An investigation of the Stillwater inch-scale layeri ng and similar layers in the Bushveld intrusion shows that the CPG pattern ing mechanism leaves a characteristic microstructural record preserving ev idence for slow super- and sub-solidus cooling with a highly interconnecte d texturally equilibrated melt phase that enhanced Ostwald ripening. The S kaergaard intrusion locally preserves cm-scale micro-rhythmic layering\, s uperimposed on single modally-graded layers. The microstructures in the Sk aergaard example do not show evidence of CPG. Furthermore\, the energy of all relevant hetero-phase interfaces is less than that of the associated g rain boundaries in igneous and metamorphic rocks\, compaction was not a si gnificant process in the Skaergaard intrusion\, and the supposition of mic ro-rhythmic layering on modally graded layers formed by sedimentation prec ludes patterning by oscillatory nucleation and growth. A new patterning me chanism is proposed\, whereby immiscible conjugate silicate liquids in the crystal mush self-organise\, due to differences in their wetting properti es in the compositionally-graded mush and the positive feedback due to the fact that the two immiscible conjugates predominantly crystallise the min erals which they preferentially wet.\nSpeakers:\nProf Marian Holness (Camb ridge) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/f0c7c04b-7938-48b7-8f4c-47b96b7f4b82/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Self-organisation in mafic cumulates: differential migrat ion of immiscible silicate liquids in the crystal mush - Prof Marian Holne ss (Cambridge) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Isotopic constraints on the formation and evolution of the Earth-M oon system - Prof Francis Nimmo (UC Santa Cruz) DTSTART;VALUE=DATE-TIME:20250228T130000Z DTEND;VALUE=DATE-TIME:20250228T140000Z UID:https://talks.ox.ac.uk/talks/id/636e9604-0456-4bfa-87c1-77981ba5a582/ DESCRIPTION:Isotopes are useful probes of planet formation and evolution f or at least two reasons. Some exhibit nucleosynthetic anomalies providing clues to their original location. Others undergo decay\, providing age con straints. In this talk\, I'll discuss two applications of these ideas. The fact that the silicate Earth records different fractions of "carbonaceous " material in different elements implies that it experienced a change in t he material it was accreting over time. The first ~95% was "non-carbonaceo us"\, while the last ~5% was "carbonaceous" and volatile-rich. Reconciling these constraints with existing planetary accretion scenarios is not easy . In the second part\, I'll discuss the idea that the pile-up of lunar age s around 4.35 Gyr is not the signature of magma ocean crystallization but is instead related to a tidal heating event. This story allows the Moon to be older (~4.45 Gyr or so)\, which is easier to reconcile with dynamical models.\nSpeakers:\nProf Francis Nimmo (UC Santa Cruz) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/636e9604-0456-4bfa-87c1-77981ba5a582/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Isotopic constraints on the formation and evolution of th e Earth-Moon system - Prof Francis Nimmo (UC Santa Cruz) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Strengths and weaknesses of large-sample machine learning for hydr oclimatic extremes - Dr Louise Slater (University of Oxford) DTSTART;VALUE=DATE-TIME:20250221T120000Z DTEND;VALUE=DATE-TIME:20250221T130000Z UID:https://talks.ox.ac.uk/talks/id/74e20f97-9cf4-44c4-8f46-8e3849b79962/ DESCRIPTION:Recent advances in large-sample hydrology using machine learni ng (ML) models have enabled significant progress\, overcoming the constrai nts of limited observations in individual locations. Large-sample models t ypically integrate historical discharge records from thousands of stream g auges with a wide range of environmental and human impacts data\, learning relationships across diverse environments to improve model performance. A t the core of our models is the GRIT river network\, a new global bifurcat ing network essential for accurate flood modelling. Our research addresses three challenges: (1) evaluating the strengths and weaknesses of ML for e stimating extreme events across data-rich and data-sparse regions\; (2) at tributing driving mechanisms\, by comparing various explainability methods and exploring the effects of human impacts\; and (3) enhancing event pred iction and projection\, by assessing the extent to which ML models trained on climate model outputs are able to correct biases and deliver reliable predictions. We also discuss challenges in large-sample modelling such as data biases\, inconsistencies in explainability\, and causality. By integr ating ML techniques and global datasets\, large-sample hydrology offers ne w opportunities for understanding and managing hydroclimatic extremes.\nSp eakers:\nDr Louise Slater (University of Oxford) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/74e20f97-9cf4-44c4-8f46-8e3849b79962/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Strengths and weaknesses of large-sample machine learning for hydroclimatic extremes - Dr Louise Slater (University of Oxford) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:From Sediment to Spodumene - Prof Claire E.Bucholz (Caltech) DTSTART;VALUE=DATE-TIME:20250314T120000Z DTEND;VALUE=DATE-TIME:20250314T130000Z UID:https://talks.ox.ac.uk/talks/id/145f8230-71a6-4777-8616-27efaa67daa8/ DESCRIPTION:In this talk I’ll synthesize recent research interrogating h ow variations in weathering regimes and sediment deposition have impacted the chemistry of igneous rocks. In particular\, I will focus on a particul ar class of granites (often termed “S-type”) which form via partial me lting of siliciclastic sedimentary rocks and are uniquely suited to captur e how the chemical consequences of sedimentary incorporation into magmas h ave varied throughout Earth history. I will focus on how enhanced organic matter and clay deposition at various periods in Earth history are reflect ed in the chemistry of the granites and the implications these variations have for our understanding of the oxygenation of Earth’s atmosphere and the occurrence of Li mineral deposits.\nSpeakers:\nProf Claire E.Bucholz ( Caltech) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/145f8230-71a6-4777-8616-27efaa67daa8/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:From Sediment to Spodumene - Prof Claire E.Bucholz (Calte ch) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Iron-rich peatlands in a warming world - Dr Casey Bryce (Universit y of Bristol) DTSTART;VALUE=DATE-TIME:20250307T120000Z DTEND;VALUE=DATE-TIME:20250307T130000Z UID:https://talks.ox.ac.uk/talks/id/e52a00ef-627b-42ff-b246-08d5b18c9d27/ DESCRIPTION:Peatlands in the northern hemisphere store vast quantities of Earth’s soil carbon\, largely thanks to the cold and wet climate which l imits decomposition of organic matter. However\, these fragile wetland sys tems are rapidly changing in response to warming temperatures\, changing p recipitation patterns\, permafrost thaw\, and drainage for agriculture or mining. All of which act to make peatlands either drier or wetter. In turn altering carbon storage and greenhouse gas emissions. To understand the f uture fate of Earth’s terrestrial carbon stores\, we must understand how peatlands will respond to these stressors. \n\nHowever\, not all peatland s are the same. Local variations in hydrology\, geology and geochemistry c an make the degradation of some peatlands complex to predict and challengi ng to mitigate. For example\, in areas rich in iron\, enhanced waterloggin g (such as is promoted by permafrost thaw) can release large quantities of previously mineral-associated carbon. On the other hand\, drainage of iro n-rich peatlands can release sulfuric acid\, iron and toxic metals which m ake them complicated to restore. Using a combination of insights from mine ralogy\, geochemistry and microbiology at peatlands across the northern he misphere\; I will discuss the role of iron in shaping peatland degradation responses and the strategies needed to protect iron-rich peatlands in the future.\nSpeakers:\nDr Casey Bryce (University of Bristol) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/e52a00ef-627b-42ff-b246-08d5b18c9d27/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Iron-rich peatlands in a warming world - Dr Casey Bryce ( University of Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Seeing into the heart of a planet: InSights from the Martian core - Dr Jessica Irving (University of Bristol) DTSTART;VALUE=DATE-TIME:20250214T120000Z DTEND;VALUE=DATE-TIME:20250214T130000Z UID:https://talks.ox.ac.uk/talks/id/4871e3d4-2637-45f5-90e7-a034be0769e2/ DESCRIPTION:How big is the Martian core? What is its composition? How does it compare to Earth’s core? The Nasa-led InSight mission placed the fir st seismometer on the surface of Mars\, collecting data for four years\, a llowing us to develop new answers to these important questions. In this se minar I will talk about how seismic data from Mars\, together with researc h from mineral physics and cosmochemistry\, have helped us to look deep in to Mars’s core. The seminar will address how the first seismically-infor med models of the whole planet were built\, as well as their implications for our understanding of core composition and evolution.\nSpeakers:\nDr Je ssica Irving (University of Bristol) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/4871e3d4-2637-45f5-90e7-a034be0769e2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Seeing into the heart of a planet: InSights from the Mart ian core - Dr Jessica Irving (University of Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Testing the permeability of the barrier separating the inner and o uter circumsolar disk - Dr Yves Marrocchi (CRPG\, Universite de Lorraine) DTSTART;VALUE=DATE-TIME:20250207T120000Z DTEND;VALUE=DATE-TIME:20250207T130000Z UID:https://talks.ox.ac.uk/talks/id/c8126d7b-df0e-4db7-a653-2d0054dad98e/ DESCRIPTION:The advent of nontraditional isotopic systems (e.g.\, Ti\, Cr\ , Mo) revealed the presence of a fundamental isotopic dichotomy between no n-carbonaceous (NC) and carbonaceous (CC) meteorites. This dichotomy refle cts the formation of their parent bodies in two genetically distinct\, con temporaneous\, but spatially separated disk reservoirs. The barrier separa ting the inner (NC) from the outer (CC) reservoir has been attributed to t he early formation of Jupiter\, a long-lived pressure maximum or evolving ice lines in the disk. As the nature of the NC/CC barrier is debated\, so is its permeability\, such that current inferences range from a hard barri er with almost no influx of outer solar system material to the inner disk\ , to a soft barrier with large amounts of outer solar system dust passing through the inner disk towards the Sun. During this seminar\, I will prese nt new isotopic measurements of NC chondrules that allows to test the perm eability of the NC-CC barrier and how the results can affect our understan ding of terrestrial planet formation.\nSpeakers:\nDr Yves Marrocchi (CRPG\ , Universite de Lorraine) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/c8126d7b-df0e-4db7-a653-2d0054dad98e/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Testing the permeability of the barrier separating the in ner and outer circumsolar disk - Dr Yves Marrocchi (CRPG\, Universite de L orraine) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Lab geophysics: using the large volume press to interpret mantle s eismology - Dr Andrew R. Thomson (UCL) DTSTART;VALUE=DATE-TIME:20250131T120000Z DTEND;VALUE=DATE-TIME:20250131T130000Z UID:https://talks.ox.ac.uk/talks/id/4f16519b-c193-4c40-9fd2-3e4a7d6aafa5/ DESCRIPTION:The chemistry\, mineralogy and temperature of Earth’s interi or are the most fundamental properties of our planet. It is these properti es combined that control Earth’s evolution\, not only of its interior bu t also of its atmosphere\, climate and surface environment over geological time. However\, studying the deep Earth is not a straightforward task as direct sampling is limited to ~ 10km depth. As such\, we have to rely on p etrology and geophysics – particularly seismology – to understand anyt hing except the near surface. \n\nFortunately\, seismic observations are a bundant\, with lateral and vertical heterogeneities normally assumed to re flect compositional or thermal anomalies. However\, seismic observations w ill only provide useful insight if they can be reliably interpreted in ter ms of composition\, mineralogy temperature and pressure. This is a major s ticking point in studies of the deep Earth\, because experimental thermoel asticity data at mantle conditions are extremely sparse. In lieu of data\, it has become common to use software predictions to interpret mantle seis mology. Whilst this approach is effective in theory\, there are several li mitations including that model predictions do not provide realistic estima tes of uncertainty and that many predictions do not match available experi mental data. Experiments in the large volume press with/without synchrotro n radiation are one approach that can be used to accurately determine the crystallography and thermoelasticity of upper mantle minerals. Here exampl es of these data from recent and ongoing studies will be presented.\nSpeak ers:\nDr Andrew R. Thomson (UCL) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/4f16519b-c193-4c40-9fd2-3e4a7d6aafa5/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Lab geophysics: using the large volume press to interpret mantle seismology - Dr Andrew R. Thomson (UCL) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:A journey through tides: Jellyfish\, dinosaurs\, and evolution - P rof Mattias Green (Bangor University) DTSTART;VALUE=DATE-TIME:20250124T120000Z DTEND;VALUE=DATE-TIME:20250124T130000Z UID:https://talks.ox.ac.uk/talks/id/478d38e8-7fc1-4b09-a89f-2c00e173036b/ DESCRIPTION:The ocean tides are a key driver of a range of Earth system pr ocesses. Tidal energy drives vertical mixing with consequences for ocean c irculation\, climate\, and biological production\, and the tidal stream tr ansport sediments\, pollutants\, and other matter through the ocean. Tides have also been proposed to be one component influencing key evolution and extinction events\, including initiating the radiation of terrestrial ver tebrates. Here\, I will use the latest series of high-resolution numerical model simulations of Phanerozoic tides to which we have applied novel tid al proxies\, including jellyfish fossils and dinosaur footprints\, and dis cuss how tides may have been a key controller of evolution events in Earth ’s history.\nSpeakers:\nProf Mattias Green (Bangor University) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/478d38e8-7fc1-4b09-a89f-2c00e173036b/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:A journey through tides: Jellyfish\, dinosaurs\, and evol ution - Prof Mattias Green (Bangor University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Unveiling Permeability Pathways in Ultramafic Rock: Potential for Natural Hydrogen Generation and CO₂ Mineralisation - Arnaud Lager (Decah ydron) DTSTART;VALUE=DATE-TIME:20241129T130000Z DTEND;VALUE=DATE-TIME:20241129T140000Z UID:https://talks.ox.ac.uk/talks/id/5c398904-2931-4c64-901c-4507daeb3640/ DESCRIPTION:The study of fluid movement within ultramafic rocks presents v aluable possibilities for sustainable energy and carbon storage\, yet much about these rocks remains unexplored. While sedimentary rocks have been s tudied extensively because of their role in oil and gas production\, ultra mafic rocks have attracted far less attention. However\, the potential for natural hydrogen (H₂) production and CO₂ mineralisation in ultramafic formations\, given their unique mineral compositions\, is promising.\n\nT his presentation will examine the still-uncertain processes that create an d influence porosity and permeability in ultramafic rocks\, with particula r focus on serpentinisation\, a reaction between water and rock that can r elease hydrogen. The existence of fluid pathways raises important question s: How do porosity and permeability emerge and evolve in these rock types? What natural processes might increase these characteristics to allow grea ter fluid flow? And how might these qualities be enhanced to support H₂ production and CO₂ storage?\n\nBIO\nArnaud Lager is a petroleum geochemi st by background with 25 years of experience in oil and gas industry\, spe cialising in CCUS and sustainable energy. He was instrumental in deliverin g multiple CCUS projects worldwide such as the Al Reyadah project in the U AE\, capturing 800\,000 tons of CO₂ annually\, and now leads Decahydron in pioneering natural hydrogen production and CO₂ mineralisation in ultr amafic rock formation.\nSpeakers:\nArnaud Lager (Decahydron) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/5c398904-2931-4c64-901c-4507daeb3640/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Unveiling Permeability Pathways in Ultramafic Rock: Poten tial for Natural Hydrogen Generation and CO₂ Mineralisation - Arnaud Lag er (Decahydron) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Can we engineer our oceans to help deliver a safe\, stable climate ? - Dr Paul Halloran (University of Exeter) DTSTART;VALUE=DATE-TIME:20241108T120000Z DTEND;VALUE=DATE-TIME:20241108T130000Z UID:https://talks.ox.ac.uk/talks/id/437784ce-3651-4f3b-986c-bc2e5920b890/ DESCRIPTION:Massive scale atmospheric Carbon Dioxide Removal is required i f we are to keep globally averaged temperature increases to below 1.5 degr ees or even 2.0 degrees by the end of the century. The ocean offers a rang e of potential ways to deliver Carbon Dioxide Removal\, and its chemistry and size present the opportunity for large scale and essentially permanent removal. Removal of atmospheric CO2 into or via the ocean however present s challenges that range from technical and scientific to environmental and regulatory. In this talk I will present the view from a small industrial scale pilot plant we are building to strip CO2 from seawater. I will discu ss the science and scientific challenges behind this approach and its appl ication\, and will explore where it fits within the landscape of possible Carbon Dioxide Removal solutions. I will finish by reflecting on opportuni ty and barriers to marine Carbon Dioxide Removal contributing at scale to our efforts to stabilise and potentially reduce atmospheric CO2 concentrat ions and therefore global temperatures.\nSpeakers:\nDr Paul Halloran (Univ ersity of Exeter) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/437784ce-3651-4f3b-986c-bc2e5920b890/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Can we engineer our oceans to help deliver a safe\, stabl e climate? - Dr Paul Halloran (University of Exeter) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:X-ray computed tomography: A modern Aladdin’s lamp to discover o rogenic gold deposits - Dr Muhammad Sayab (The Geological Survey of Finlan d GTK) DTSTART;VALUE=DATE-TIME:20241206T120000Z DTEND;VALUE=DATE-TIME:20241206T130000Z UID:https://talks.ox.ac.uk/talks/id/da94f48a-286d-45c8-a4cc-694aaed03be2/ DESCRIPTION:The Suurikuusikko gold deposit in the Central Lapland Greensto ne Belt of northern Finland is the largest primary gold-producing mine in Europe\, located on the strike-slip Kiistala shear zone (KiSZ). Gold is re fractory\, occurs either as lattice-bound or submicron-scale gold inclusio ns\, and is mainly locked within arsenopyrite. A small proportion of visib le gold also occurs along fractures. In this study\, we used lab-based and synchrotron radiation–based X—ray computed microtomography and nanoto mography\, respectively\, to visualize and quantify rock volumes in a 3D s pace. This rapidly evolving non-invasive technology provides a holistic ap proach of textural analysis that eliminates interpretative procedures asso ciated with 2D methods. The 3D volume can be used to create virtual cross- sections at any desired angle or a 3D rendering\, and quantitatively analy zed with image processing software\, which act as “Genie of the Aladdin ’s lamp”. The technique revealed a kinematic history and a number of i n situ quantitative aspects including size\, shape\, spatial distribution\ , and geometrical orientation of arsenopyrite and pyrite in a highly alter ed host-rock matrix. Quantitative data highlight the spatial orientation o f the long axes (X) of arsenopyrite crystals. Most crystals show a preferr ed orientation reflecting deformation-induced crystallization and/or remob ilization and reprecipitation\, where three dominant classes can be recogn ized based on the spatial distribution of arsenopyrite crystals. Each clas s can be related to the regional-scale deformation events. The method sign ificantly helped in classifying the mineralized (gold-bearing) vs. unminer alized clusters of arsenopyrite and in depicting the geometry of the ore z ones. The workflow of analyzing orogenic gold from micro- to nanoscale off ers an indispensable new method in characterizing 3D textural settings of ores\, which could be further integrated with trace element analysis using LA-ICP-MS and in situ XRF imaging. Different ages were obtained from low- and high-strained samples using LA-ICP-MS U-Pb monazite and xenotime geoc hronology ranging from ca. 1930 to 1794 Ma\, corresponding to the differen t tectonic events of the Svecofennian orogeny. The ca. 1930 to 1900 Ma age group related to the basin inversion and D1 thrusting phase along the KiS Z. We infer that the primary gold-bearing fluids were infiltrated along th e thrust splays during this event. The ca. 1834-1794 Ma age group compleme nts the strike-slip kinematics of the gold-bearing (refractory) arsenopyri te crystals. The youngest age of ca. 1774 Ma represents the late semi-brit tle event\, where the lattice bound or submicron gold inclusions exsolved from the arsenopyrite crystal structure and precipitated along secondary f ractures. \nSpeakers:\nDr Muhammad Sayab (The Geological Survey of Finland GTK) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/da94f48a-286d-45c8-a4cc-694aaed03be2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:X-ray computed tomography: A modern Aladdin’s lamp to d iscover orogenic gold deposits - Dr Muhammad Sayab (The Geological Survey of Finland GTK) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Utilising the potential of large-N seismology: Monitoring water in the critical zone - Prof James Hammond (Birkbeck\, University of London) DTSTART;VALUE=DATE-TIME:20241101T120000Z DTEND;VALUE=DATE-TIME:20241101T130000Z UID:https://talks.ox.ac.uk/talks/id/c92e3a6a-ef95-4ecc-91b1-081c0f9c1dba/ DESCRIPTION:The deployment of low cost\, lightweight\, low power seismic n odes\, or the use of fibre optic cables as distributed acoustic sensors ha ve allowed seismologists to move from deployments of 10s of broadband seis mometers over wide areas\, to deployments of hundreds or thousands of sens ors in much denser networks – so called large-N seismology. This has led to vast improvements in traditional seismological methods\, lowering the magnitude of completeness of earthquake catalogues or improving the resolu tion of seismic images. These new advances in technology are also opening new applications for passive seismology\, especially in the field of envir onmental seismology. In this talk I will introduce a new project that uses seismic nodes to study the critical zone\, the so-called skin of our plan et between the solid Earth and fluid atmosphere. In a collaboration with S tryde\, the UK Centre for Hydrology and Ecology and Scotland’s Rural Col lege\, we deployed 1600 seismic nodes with 5-10 m spacing in a farm in Dum fries\, Scotland. Using seismic ambient noise coda wave interferometry\, we can constrain small velocity changes with 10m spatial resolution and 30 minute temporal resolution at seismic frequencies sensitive to the top fe w metres of the Earth. These velocity changes show remarkable correlations with in-situ measurements of soil moisture\, showing the potential for pa ssive seismology to be a new way to monitor soil moisture that can fill th e existing temporal and spatial sampling gap between point measurements an d those based on satellite data. Further\, we captured a significant peri od of flooding in the Dumfries area and show that the relationship between seismic velocity and soil moisture breaks down ~1 day before flooding occ urs. We relate this to soil saturation occurring at depth before being obs erved at more shallow depths. This suggests it could offer a potential mon itor for soil saturation at depth\, valuable information when monitoring p otential flood risk.\nSpeakers:\nProf James Hammond (Birkbeck\, University of London) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/c92e3a6a-ef95-4ecc-91b1-081c0f9c1dba/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Utilising the potential of large-N seismology: Monitoring water in the critical zone - Prof James Hammond (Birkbeck\, University of London) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The Shuram anomaly: What caused the largest ever carbon isotope an omaly and what can it tell us? - Prof Graham Shields (UCL) DTSTART;VALUE=DATE-TIME:20241129T120000Z DTEND;VALUE=DATE-TIME:20241129T130000Z UID:https://talks.ox.ac.uk/talks/id/a759b09e-20dd-45a7-a21c-8776102ffae9/ DESCRIPTION:The late Ediacaran Shuram anomaly is the largest carbon isotop e excursion of the entire marine sedimentary record\, with an amplitude of about 15‰. It was first reported in 1993 in separate studies from Oman\ , Australia and Russia\, since which time it has been identified all over the world in strata aged between about 580 and 560 Ma. Although repeatedly assigned to biased sampling\, it is more parsimoniously assigned to a sus tained perturbation to the global carbon cycle. The Shuram anomaly is now known to be sandwiched between two major glaciations but is itself associa ted with global warming and biological radiations of benthic animals acros s an increasingly oxidised seafloor. Low organic burial rates during the Shuram anomaly are consistent with independent evidence for highly effici ent organic remineralisation\, implying net transfer of oxidising power fr om rock sulphate to the carbon cycle. Other negative anomalies occurred be tween 1.6 and 0.5 Ga\, and preceded all Neoproterozoic glaciations. This t alk will consider whether ‘sink-switching’ between the sulphur and car bon rock reservoirs was a defining characteristic of the Proterozoic Earth system. \nSpeakers:\nProf Graham Shields (UCL) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/a759b09e-20dd-45a7-a21c-8776102ffae9/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The Shuram anomaly: What caused the largest ever carbon i sotope anomaly and what can it tell us? - Prof Graham Shields (UCL) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Paleogeography of the southern Eurasian margin in the lead-up to I ndia-Eurasia collision - Dr Craig Martin (University of Texas at Austin) DTSTART;VALUE=DATE-TIME:20241122T120000Z DTEND;VALUE=DATE-TIME:20241122T130000Z UID:https://talks.ox.ac.uk/talks/id/9f660614-b575-4010-8baa-fe13d8631df1/ DESCRIPTION:Prior to the India-Eurasia collision\, the southern Eurasian m argin either resembled a Cordillera-style accretionary orogen or a complex Japan-Mariana-style margin with extended back-arc basins and oceanic crus t separating volcanic arc(s) from Eurasian continental lithosphere. Distin guishing between these alternative scenarios has implications for the conv ergence history of India and Eurasia\, the development of the India-Eurasi a collision zone\, and the post-collision structure of the Himalayan oroge n. In this presentation I will overview the geological constraints on the India-Eurasia collision in Northwest India and Pakistan\, which show that a significant back-arc basin developed in the Late Cretaceous between the Kohistan-Ladakh arc and Eurasia. The Kohistan-Ladakh arc initially intrude d a Jurassic forearc ophiolite at the southern edge of Eurasia before drif ting southward in the Late Cretaceous during a period of Neotethyan slab r ollback. The southward migration of the Kohistan-Ladakh arc away from Eura sia persisted until the Paleocene accretion of the Kohistan-Ladakh arc ont o India. Final India-Eurasia continental collision occurred in the Lutetia n when the Karakoram terrane was thrust over the Kohistan-Ladakh arc durin g the formation of the Shyok suture zone. So\, at least in the western Him alaya\, the Late Cretaceous to Paleocene southern Eurasian margin more clo sely resembled a Japan-Mariana-style system than a Cordilleran-style oroge n. This conclusion is consistent with the paleogeography of the Neotethys Ocean to the East and West of the India-Eurasia collision zone\, which is typified by complex southward arc migration\, back-arc basin development\, and multiple collision events. \nSpeakers:\nDr Craig Martin (University o f Texas at Austin) LOCATION:Seminar Rooms TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/9f660614-b575-4010-8baa-fe13d8631df1/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Paleogeography of the southern Eurasian margin in the lea d-up to India-Eurasia collision - Dr Craig Martin (University of Texas at Austin) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Vanadium isotopes: 15 years retrospective and future research pros pects - Prof Julia Pryulak (Durham University) DTSTART;VALUE=DATE-TIME:20241115T120000Z DTEND;VALUE=DATE-TIME:20241115T130000Z UID:https://talks.ox.ac.uk/talks/id/2e30d8e8-cfaf-49c5-8758-619cbdfd014a/ DESCRIPTION:The element vanadium (V) has been applied to challenges spanni ng Earth and Environmental Sciences. It is a critical metal\, with indust ry applications in next generation batteries and as a steel alloy. It has rich redox chemistry with multiple oxidation states\, prompting decades of oxygen fugacity (fO2) proxy development at high and low temperatures\, on Earth and other planets. Some organisms even employ V in place of iron to carry oxygen in their bloodstreams. However\, vanadium\, in its 5+ oxida tion state is also highly toxic and is increasing recognised as a potentia lly serious environmental pollutant. The isotopic composition of vanadium can be applied to investigate all of the above scenarios. The first method to measure V isotopes to a precise useful for Earth and environmental sci ence applications was developed in the Earth Science department at Oxford circa 2009. In this seminar\, I will discuss how that analytical developme nt unfolded\, and how the applications of vanadium isotopes have evolved f rom initial lofty ambitions of a direct fO2 proxy in magmatic systems to c urrent potential breakthroughs in environmental pollutant tracing.\nSpeake rs:\nProf Julia Pryulak (Durham University) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/2e30d8e8-cfaf-49c5-8758-619cbdfd014a/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Vanadium isotopes: 15 years retrospective and future rese arch prospects - Prof Julia Pryulak (Durham University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Dynamics of natural landslides from numerical modelling and seismi c inversion - Prof Anne Mangeney (Université Paris Cité) DTSTART;VALUE=DATE-TIME:20241018T120000 DTEND;VALUE=DATE-TIME:20241018T130000 UID:https://talks.ox.ac.uk/talks/id/984f5526-7577-4129-a81e-4d9eb876fdd0/ DESCRIPTION:One of the major challenges facing our society is to cope with the increase in natural hazards caused by climate change\, human activity and population growth. The frequency of heavy rainfall and changes in veg etation cover are intensifying in most regions\, greatly increasing the ri sk of landslides and the tsunamis they generate.\n\nExact prediction of th e time\, location and precise characteristics of a landslide is generally out of reach. However\, it is possible to anticipate hazards by numericall y simulating a series of probable scenarios using granular flow models on realistic topographies. However\, there are two major obstacles to the use of these models. Firstly\, the frictional behavior of these natural flows remains highly enigmatic\, and most models fail to describe processes tha t play an important role at field scale\, such as the interaction between grains and a fluid phase. On the other hand\, very little data is availabl e on the dynamics of these flows. In this context\, the analysis of landsl ide-generated seismic waves coupled with the development of mathematical\, physical and numerical models of granular flows on complex topography ope ns a unique opportunity to address this challenge.\n\nI will present recen t studies we have carried out with mathematicians and physicists to quanti fy landslide dynamics in order to assess the associated hazards. A key asp ect of this work is to successfully couple state-of-the-art numerical simu lation of these complex rheological flows with seismic wave analysis\, mov ing back and forth between laboratory and field scales. I will describe th e challenges posed in terms of modeling\, such as dilatancy effects in a g rain/fluid mixture\, wave-flow interaction\, and the relevance of multilay er Saint-Venant-type approaches.\nSpeakers:\nProf Anne Mangeney (Universit é Paris Cité) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/984f5526-7577-4129-a81e-4d9eb876fdd0/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Dynamics of natural landslides from numerical modelling a nd seismic inversion - Prof Anne Mangeney (Université Paris Cité) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Active plate tectonics in the Paleoarchean - Dr Simon Lamb (Victor ia University of Wellingon\, New Zealand) DTSTART;VALUE=DATE-TIME:20241025T120000 DTEND;VALUE=DATE-TIME:20241025T130000 UID:https://talks.ox.ac.uk/talks/id/b70e92de-2ede-4184-9389-24d90f428b29/ DESCRIPTION:Plate tectonics has played a major role in the Earth’s evolu tion\, both in the cooling of the planetary interior\, and\, it is widely argued\, the maintenance of liquid water and life at the surface. But was the Earth always like this? The answer to this question is most likely to lie in relicts of the early Earth’s surface\, preserved in Archean green stone belts and found in almost all the cratons. In this talk\, I compare field relations in the 3.5 – 3.2 Ga Barberton Greenstone Belt (BGB) in S outh Africa and Eswatini with the active New Zealand subducting plate-boun dary zone. I show that there are remarkable similarities in structure and stratigraphy\, with many of the distinctive features of convergent plate m argins\, and I argue that the simplest explanation is that plate tectonics was fully active in the Paleoarchean\, generating great earthquakes on th e subduction megathrust and growth folds and major low angle thrusts in th e overlying accretionary prism and subsequent continental collision.\n\n \ n\nOceania in the SW Pacific may provide us with the closest modern exampl e of the surface of the Paleoarchean Earth\, forming a water world with ac tive volcanoes\, back-arc spreading and small continental landmasses along a subducting plate boundary with local continental collision. In fact\, t he eruption of boninites here in the back-arc region may be a direct analo gy for the typical komatiitic volcanism in the early Earth. The explosive eruption of Hunga Volcano near Tonga in 2022 could even provide clues to t he origin of life\, suggesting that life was born out of the extreme viole nce of plate tectonics\, a far cry from Darwin’s benign and warm little pond!\nSpeakers:\nDr Simon Lamb (Victoria University of Wellingon\, New Ze aland) LOCATION:Department of Earth Sciences (Seminar Rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/b70e92de-2ede-4184-9389-24d90f428b29/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Active plate tectonics in the Paleoarchean - Dr Simon Lam b (Victoria University of Wellingon\, New Zealand) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Risky Mountains in Paradise: Navigating the Volcanic Tapestry of I sland Life - Prof Richard Robertson (UWI) DTSTART;VALUE=DATE-TIME:20240614T120000 DTEND;VALUE=DATE-TIME:20240614T130000 UID:https://talks.ox.ac.uk/talks/id/353b8901-b6c0-4352-ab28-acdaf0ae8b0d/ DESCRIPTION:Life in the multi-hazard volcanic landscape in the Eastern Car ibbean can be challenging\; but through ongoing collaboration between moni toring scientists\, government agencies and at-risk communities\, crises c an be effectively managed. In this talk Richie will share examples and les sons learned during his work in the region directed at reducing risk from volcanic activity. This includes\, developing innovative\, cost-effective monitoring solutions\, engaging with communities\, advancing knowledge of volcanic systems through partnerships with research institutions\, and emb racing new technologies\nSpeakers:\nProf Richard Robertson (UWI) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/353b8901-b6c0-4352-ab28-acdaf0ae8b0d/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Risky Mountains in Paradise: Navigating the Volcanic Tape stry of Island Life - Prof Richard Robertson (UWI) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Zircon and Plagioclase Chronicles of Volcano-Magmatic Evolution - Prof Oleg Melnik (Oxford) DTSTART;VALUE=DATE-TIME:20240531T120000 DTEND;VALUE=DATE-TIME:20240531T130000 UID:https://talks.ox.ac.uk/talks/id/a74aed7e-098f-4754-8054-c3dcc20177fb/ DESCRIPTION:Unraveling dynamics of volcano-magmatic systems remains a grea t challenge due to absence of direct observations of magma formation\, sto rage or eruptions. Recent advances in analyzing minerals like zircon or pl agioclase offer a window into these hidden processes.\n\nZircon\, a remark ably resistant mineral\, can grow for many thousands of years within slowl y cooling magma chambers. Despite this slow crystallization\, these crysta ls retain signatures of disequilibrium trace element partitioning (e.g.\, Hf\, Y\, U\, Th) and Zr isotopic fractionation due to diffusion. Simulatio n of these processes transforms zircon crystals to thermometers and clocks \, recording the thermal evolution of individual magma parcels.\nPlagiocla se\, another key witness\, offers insights into pre-eruptive magma ascent and storage conditions. Core-to-rim variations in Anorthite content\, Sr\, and Ba concentrations reflect changes in pressure and temperature providi ng valuable clues about the complex dynamics leading up to an eruption.\nS peakers:\nProf Oleg Melnik (Oxford) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/a74aed7e-098f-4754-8054-c3dcc20177fb/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Zircon and Plagioclase Chronicles of Volcano-Magmatic Evo lution - Prof Oleg Melnik (Oxford) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Volcanic whodunnit: new methods to unravel the source and climate impact of past eruptions - Dr William Hutchison (St Andrews) DTSTART;VALUE=DATE-TIME:20240524T120000 DTEND;VALUE=DATE-TIME:20240524T130000 UID:https://talks.ox.ac.uk/talks/id/35b20622-627f-4c9b-a7be-ac6498c5fca7/ DESCRIPTION:The polar ice cores represent our most detailed archive of lar ge magnitude volcanic eruptions. Yet\, for the majority of these eruptions we have no idea where the source volcano was located nor whether its ash and sulfur emissions made it to the stratosphere. This information is crit ical for understanding the climate and societal impacts of past eruptions. Our group at St Andrews is developing a new isotopic and tephra analytica l tool kit to extract this key information from volcano ice core archives. Here\, I will talk about a particularly fascinating period at the end of the Little Ice Age\, 1800–1850 CE\, which is the coldest period in the l ast 500 years and was marked by cluster of mysterious volcanic events.\nSp eakers:\nDr William Hutchison (St Andrews) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/35b20622-627f-4c9b-a7be-ac6498c5fca7/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Volcanic whodunnit: new methods to unravel the source and climate impact of past eruptions - Dr William Hutchison (St Andrews) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Peering beneath the ice: observing the ocean under Antarctica’s floating ice shelves - Dr Peter Davis (British Antarctic Survey (BAS)) DTSTART;VALUE=DATE-TIME:20240517T120000 DTEND;VALUE=DATE-TIME:20240517T130000 UID:https://talks.ox.ac.uk/talks/id/ffc84d43-7dfe-4b49-909b-c04a02664a2e/ DESCRIPTION:\nSpeakers:\nDr Peter Davis (British Antarctic Survey (BAS)) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/ffc84d43-7dfe-4b49-909b-c04a02664a2e/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Peering beneath the ice: observing the ocean under Antarc tica’s floating ice shelves - Dr Peter Davis (British Antarctic Survey ( BAS)) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Tracing the fossil\, genomic and mineral footprints of Earth’s m icrobial past - Prof Tanja Bosak (MIT) DTSTART;VALUE=DATE-TIME:20240510T120000 DTEND;VALUE=DATE-TIME:20240510T130000 UID:https://talks.ox.ac.uk/talks/id/53406cc0-1744-4378-8b2d-4e037c851c1d/ DESCRIPTION:The interplay among environmental chemistry\, organismal evolu tion and microbial stress responses contributed to the preservation of a n early 3.5 billion-year long record of microbial life by silica\, carbonate and clay minerals. In this talk\, I will use the genomic and fossil recor ds of Cyanobacteria\, the organismal lineage with the oldest fossil record \, to ask when this photosynthetic lineage evolved the critical ability to produce oxygen. I will then present results of experimental work that sho ws the ability of cyanobacteria to promote their own fossilization by prec ipitating silica and carbonate minerals. These results help constrain the concentrations of silica in marine environments more than two billion year s ago\, explain the preservation of exquisite cyanobacterial fossils in ch ert lenses associated with Proterozoic carbonate deposits and can inform t he search for signs of past life on Mars.\nSpeakers:\nProf Tanja Bosak (MI T) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/53406cc0-1744-4378-8b2d-4e037c851c1d/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Tracing the fossil\, genomic and mineral footprints of Ea rth’s microbial past - Prof Tanja Bosak (MIT) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Map of the Arctic indicating samples collected during the CAO ARIS E project - Prof Claire Mahaffey (Liverpool) DTSTART;VALUE=DATE-TIME:20240503T120000 DTEND;VALUE=DATE-TIME:20240503T130000 UID:https://talks.ox.ac.uk/talks/id/242e50da-e470-410a-ab61-32f4ff719dea/ DESCRIPTION:Warming of the Arctic is altering the physical environment\, r educing sea ice cover and melting glaciers at unprecedented rates. The res ponse of primary productivity by phytoplankton to enhanced light availabil ity or increased glacial inflow will hinge on the availability of nutrient resources\, especially nitrogen. Here\, I will summarise our findings fro m the Changing Arctic Ocean programme on nutrient dynamics\, cleaned from analysis of historical data sets and stable nitrogen isotopes. I will intr oduce new observations on the occurrence of marine nitrogen fixation in th e cold Arctic Ocean and discuss implications for the future Arctic ecosyst em. \nSpeakers:\nProf Claire Mahaffey (Liverpool) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/242e50da-e470-410a-ab61-32f4ff719dea/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Map of the Arctic indicating samples collected during the CAO ARISE project - Prof Claire Mahaffey (Liverpool) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:To Bennu and Back: First Results from the OSIRIS-REx Asteroid Samp le Return Mission - Dr Ashley King (Natural History Museum) DTSTART;VALUE=DATE-TIME:20240426T120000 DTEND;VALUE=DATE-TIME:20240426T130000 UID:https://talks.ox.ac.uk/talks/id/671f4994-aaba-4728-89b6-b7ae403bc9e4/ DESCRIPTION:In September 2023\, NASA’s OSIRIS-REx spacecraft completed a 7-year mission to return a pristine sample of the asteroid Bennu to Earth . Bennu is rich in carbon and water and holds important clues about the pr ocesses and events that shaped the evolution of habitable environments in the early Solar System. I’ll talk about the initial curation and analysi s of the returned samples and what we’ve discovered about the compositio n of Bennu so far.\nSpeakers:\nDr Ashley King (Natural History Museum) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/671f4994-aaba-4728-89b6-b7ae403bc9e4/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:To Bennu and Back: First Results from the OSIRIS-REx Aste roid Sample Return Mission - Dr Ashley King (Natural History Museum) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Searching for habitability on Venus and exoplanets DTSTART;VALUE=DATE-TIME:20240223T120000Z DTEND;VALUE=DATE-TIME:20240223T130000Z UID:https://talks.ox.ac.uk/talks/id/06643a9e-01b2-487e-aae0-040cfd698b67/ DESCRIPTION:Venus today presents a type example of how habitability can fa il to persist on a planet: rocky and to a first order overwhelmingly Earth -like\, but with a climate profoundly hostile to life’s complex molecula r machinery. But\, was it always like this and will we know a Venus from an Earth when we see one elsewhere in the galaxy? This talk investigates what evidence there may be for Venus’s past climate state\, and relates this to the frontier of our search for habitable conditions on exoplanets . LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/06643a9e-01b2-487e-aae0-040cfd698b67/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Searching for habitability on Venus and exoplanets TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Harnessing Earth's Vibrations and Leading Open Science Initiatives in Earth Sciences DTSTART;VALUE=DATE-TIME:20240209T120000Z DTEND;VALUE=DATE-TIME:20240209T130000Z UID:https://talks.ox.ac.uk/talks/id/252147ea-b141-4fa0-b2e6-88aba10a2d38/ DESCRIPTION:I propose to explore the potential of utilizing Earth's noise\ , specifically microseisms and anthropogenic signatures\, in interesting ( and fun) research. We will then delve into the transformative power of Ope n Science\, emphasizing the significance of sharing codes\, knowledge\, fo stering large global collaborations\, and advocating for the adoption of d iamond open access journals.\nPart 1: Research on/using Earth's Noise\nEar th's noise\, encompassing natural and human-induced vibrations\, presents a wealth of untapped information. This part of the seminar will highlight some of the latest advancements in utilizing continuous seismic data\, or “noise”. Noise is composed of low-frequency seismic waves generated by oceanic and atmospheric processes and anthropogenic sources such as traff ic\, industrial activities\, and mining. The analysis of continuous seismi c data\, acquired digitally since 1976 (Gräfenberg network\, Germany) and “standard practice” today\, provides powerful tools for investigating Earth's structure and processes. We will give a special focus on the anal ysis of volcanic tremor or monitoring climate change impacts.\nPart 2: Ope n Science: Sharing Codes\, Knowledge\, and Global Collaboration\nOpen Scie nce is the driving force behind scientific progress. We will emphasize the importance of openness\, transparency\, and cross-disciplinary collaborat ion to maximize the scientific impact in Earth Sciences. We will discuss t he advantages of openly sharing codes\, enabling reproducibility of resear ch\, facilitating rapid advancements\, and promoting innovative discoverie s. We will also advocate for the adoption and support of diamond open acce ss journals\, which provide freely accessible research outputs\, for all. Furthermore\, I will shed light on the imperative need for a shift in the evaluation of researcher's careers\, emphasizing the adoption of principle s outlined in the San Francisco Declaration on Research Assessment (DORA). By recognizing the significance of research quality\, integrity\, and ope n dissemination over traditional metrics such as journal impact factors\, Earth Sciences can foster a more inclusive and equitable research culture that values diverse contributions and encourages open collaboration.\n LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/252147ea-b141-4fa0-b2e6-88aba10a2d38/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Harnessing Earth's Vibrations and Leading Open Science In itiatives in Earth Sciences TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The fastest and furthest-travelling flows on Earth: New insights f rom direct monitoring of deep-sea hazards - Dr Mike Clare (National Oceano graphy Centre\, Southampton) DTSTART;VALUE=DATE-TIME:20240126T120000Z DTEND;VALUE=DATE-TIME:20240126T130000Z UID:https://talks.ox.ac.uk/talks/id/94802eb7-2478-4ed2-90e5-2ebb3507be4c/ DESCRIPTION:Despite covering two thirds of our planet\, the ocean remains largely unmonitored with respect to the diversity of natural hazards that can occur in the deep sea. These hazards represent some of the largest pro cesses on Earth and include underwater landslides that dwarf their onshore equivalents\, avalanches of sand and mud (called turbidity currents) that can transport huge volumes of sediment for 1000s of kilometres into the d eep-sea\, and submerged volcanoes that can trigger seafloor flows that tra vel at >100 km/hour. Our first understanding of these hazards came from da mage to seafloor infrastructure such as telecommunications cables and the impacts on coastal communities of the tsunamis they created. Reliance on s eafloor and coastal infrastructure is ever-growing\; hence understanding t hese hazards is increasingly important. For example\, >99% of all digital data traffic worldwide is now carried via a network of 1.4 million km of s eafloor cables. This presentation shares new insights into the largest and furthest travelling flows on the planet based on novel direct monitoring and damage to critical infrastructure in deep sea sites from the Congo Can yon (West Africa)\, the Whittard Canyon (North Atlantic)\, and Hunga Volca no (South Pacific)\, and outlines some lessons learned to design more resi lient infrastructure to ensure continuity in global connectivity.\nSpeaker s:\nDr Mike Clare (National Oceanography Centre\, Southampton) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/94802eb7-2478-4ed2-90e5-2ebb3507be4c/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The fastest and furthest-travelling flows on Earth: New i nsights from direct monitoring of deep-sea hazards - Dr Mike Clare (Nation al Oceanography Centre\, Southampton) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Oceanic transform faults revisited - Prof. Dr. Ingo Grevemeyer (GE OMAR Helmholtz Centre for Ocean Research Kiel\, Germany) DTSTART;VALUE=DATE-TIME:20240216T110000Z DTEND;VALUE=DATE-TIME:20240216T120000Z UID:https://talks.ox.ac.uk/talks/id/f1e2c515-5344-4f7f-9595-e174a698eca7/ DESCRIPTION:Transform faults represent one of three classes of plate bound aries and show strike-slip tectonism where one plate moves past another an d hence are called conservative plate margins where crust is neither forme d nor destructed. The other two types of plate boundaries are divergent an d hence extensional plate boundaries where new crust is formed (mid-ocean ridges\, MOR) and convergent or destructive plate margins (subduction zone s) where crust is recycled back into Earth’s interior. Researcher focuse d their attention on MOR and subduction zones\, but transform faults garne red rather little attention over the last decades\, especially in ocean ba sins.\nOceanic transform faults (OTF) are gigantic features – up to 900 km long – and without oceans masking the seafloor\, they would be among the most prominent features on Earth\, offsetting mid-ocean ridges\, formi ng tens of kilometres wide and up to 7 km deep valleys on the ocean floor. Yet\, they are defined as simple strike-slip faults\, but how can a trans current plate boundary\, generating magnitude 7+ strike-slip earthquakes\, promote extension forming the deep and wide valleys? Furthermore\, for ov er half a century\, researchers failed to appreciate that OTF are always d eeper than adjacent oceanic features of an older age\, challenging a major concept of plate tectonics. Thus\, instead of showing the predicted age-d ependent subsidence\, the seafloor shallows at ridge-transform intersectio ns (RTI). It therefore might be reasonable to question if they are indeed conservative plate boundaries.\nI will provide observational evidence sugg esting that OTFs are highly dynamic features\, showing two phases of accre tion at both RTIs. In addition\, they may suffer from extensional tectonic s below their strike-slip surface fault zone. In my presentation I’m goi ng to show that we may need to revise our concept of transform faults and will show constraints from a global compilation of bathymetric data\, show predictions from numerical simulations and will dive into a pilot study o f micro-seismicity at the the Oceanographer transform at the Mid-Atlantic Ridge near 35°N. The micro-earthquake activity captured by a network of o cean-bottom-seismometers reveals a diffuse activity over a broad area\, cu tting across the inside corner domain between the spreading centre and the transform fault before focusing along the trace of the fault. In the vici nity of the ridge-transform intersection\, focal mechanisms reveal transfo rm-normal extensional tectonics instead of showing transcurrent motion\, w hile strike-slip tectonics occurs only >15 km away from adjacent spreading segments. These observations support a scenario based on numerical simula tions showing that at RTIs the right-angular plate boundary at the seafloo r develops into an oblique shear zone at depth\, causing crustal thinning and consequently forming transform valleys. Away from RTIs\, seismicity is focused at a narrow and segmented strike-slip fault system as predicted b y plate tectonics. However\, tectonic processes shaping transforms are div ers\, arguing for a revision of the concept of conservative plate boundari es to account for their morphology and strong lateral differences in seism ic behaviour.\nSpeakers:\nProf. Dr. Ingo Grevemeyer (GEOMAR Helmholtz Cent re for Ocean Research Kiel\, Germany) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/f1e2c515-5344-4f7f-9595-e174a698eca7/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Oceanic transform faults revisited - Prof. Dr. Ingo Greve meyer (GEOMAR Helmholtz Centre for Ocean Research Kiel\, Germany) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Exploring the stability of the Antarctic Ice Sheet - Dr Ronja Rees e (Northumbria) DTSTART;VALUE=DATE-TIME:20240202T120000Z DTEND;VALUE=DATE-TIME:20240202T130000Z UID:https://talks.ox.ac.uk/talks/id/19c08909-c545-4793-a738-876cd9e8f7a2/ DESCRIPTION:Observations of ocean-driven grounding line retreat in the Amu ndsen Sea Embayment in Antarctica raise the question of an imminent collap se of the West Antarctic Ice Sheet. This would raise global sea levels by more than three metres. A collapse would be caused by irreversible retreat of the ice sheet's grounding line - the position where the formerly groun ded ice starts to float - due to a so-called Marine Ice Sheet Instability. Here we analyse whether Antarctic grounding lines are undergoing a Marine Ice Sheet Instability in their current position. Furthermore\, we investi gate the committed evolution of Antarctic grounding lines under present-da y ocean and atmospheric conditions and put this into the paleo-context\, i n order to understand the current stability of the (West) Antarctic Ice Sh eet.\nSpeakers:\nDr Ronja Reese (Northumbria) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/19c08909-c545-4793-a738-876cd9e8f7a2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Exploring the stability of the Antarctic Ice Sheet - Dr R onja Reese (Northumbria) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Salty waters: Life’s origins and biological habitability on Eart h and Mars - Dr Benjamin Tutolo (University of Calgary) DTSTART;VALUE=DATE-TIME:20240308T120000Z DTEND;VALUE=DATE-TIME:20240308T130000Z UID:https://talks.ox.ac.uk/talks/id/21b61529-5e9f-4df8-a763-60ea0d4548da/ DESCRIPTION:How did life begin? It is a question so fundamental that it ha s been pondered since the dawn of human civilization. As scientists have s ought answers to this question and its logical derivative – Are we alone in the universe? – a common strategy\, “follow the water\,” has eme rged. In this presentation\, I will discuss recent efforts to understand t he vital role of solute-laden\, “salty” waters in fostering habitabili ty on ancient Earth and Mars. I will focus on the ways that water-driven g eochemical reactions generate habitable conditions\, and their potential f or originating Earth’s first organisms. My discussion will be informed b y intensive study of modern and ancient hydrothermal systems\, geochemical and geophysical surveys of unique\, saline lakes in British Columbia (Can ada)\, and the Mars Science Laboratory Curiosity rover’s ongoing explora tion of Gale Crater\, Mars.\nSpeakers:\nDr Benjamin Tutolo (University of Calgary) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/21b61529-5e9f-4df8-a763-60ea0d4548da/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Salty waters: Life’s origins and biological habitabilit y on Earth and Mars - Dr Benjamin Tutolo (University of Calgary) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Mineralogical controls on climate and oxygenation - Prof Caroline Peacock (University of Leeds) DTSTART;VALUE=DATE-TIME:20240301T120000Z DTEND;VALUE=DATE-TIME:20240301T130000Z UID:https://talks.ox.ac.uk/talks/id/729cbd73-d263-4495-ad72-33e2359eb739/ DESCRIPTION:The preservation of organic carbon in marine sediments is fund amentally important for Earth’s carbon and oxygen cycles\, but the contr ols on carbon preservation remain unclear. Preservation can be enhanced by limiting exposure of carbon to oxygen\, but on continental margins\, wher e the majority of carbon preservation occurs\, the relationship between ox ygen exposure and burial efficiency is weak. In these environments in part icular\, additional preservation mechanisms are proposed\, including the p rotection and preservation of carbon with sediment minerals. We show that the sorption of carboxyl-rich carbon [1] and its chemical transformation [ 2] with reactive forms of iron and manganese provides a hitherto unrecogni sed mechanism for the stabilisation and preservation of carbon in sediment s\, such that the flux of iron and manganese into the oceans may provide a new control on planetary climate and oxygenation [2\,3].\n\nSpeakers:\nPr of Caroline Peacock (University of Leeds) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/729cbd73-d263-4495-ad72-33e2359eb739/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Mineralogical controls on climate and oxygenation - Prof Caroline Peacock (University of Leeds) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:A cobra effect in a greening world: can Earth scientists find the antivenin? - Prof Cyril Chelle-Michou\, (ETH Zurich) DTSTART;VALUE=DATE-TIME:20240119T120000Z DTEND;VALUE=DATE-TIME:20240119T130000Z UID:https://talks.ox.ac.uk/talks/id/27fa5d61-0b7e-40bd-a5cf-2a4a535829bc/ DESCRIPTION:The planned energy transition signed by world’s nations in t he Paris agreement sets the target to phase out fossil fuels by mid-centur y. This “green reset” requires a build-up of fossil fuel-free energy c apacities (in production\, end-use\, and storage) which will entail on an unprecedented demand in mineral resources. While the Earth crust hosts suc h resource in sufficient quantities\, I will highlight the key bottlenecks in bringing these metals to the market and show that the target cannot be met in the allocated timeframe. Finally\, I will explore the way earth sc ientists can cushion the commodity race until nations decide on and implem ent a better plan.\nSpeakers:\nProf Cyril Chelle-Michou\, (ETH Zurich) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/27fa5d61-0b7e-40bd-a5cf-2a4a535829bc/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:A cobra effect in a greening world: can Earth scientists find the antivenin? - Prof Cyril Chelle-Michou\, (ETH Zurich) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Atmospheric loss in giant impacts: The effect of pre-impact surfac e conditions\; Research seminar with Dr Simon Lock - Dr Simon Lock (Univer sity of Bristol) DTSTART;VALUE=DATE-TIME:20231027T120000 DTEND;VALUE=DATE-TIME:20231027T130000 UID:https://talks.ox.ac.uk/talks/id/bd473dfa-0a9c-4f96-ad64-d0d326c7b636/ DESCRIPTION:Earth likely acquired a significant fraction of its volatile e lements during the main stages of accretion. The atmospheres of the planet ary embryos that accreted to form Earth must therefore have survived the g iant impacts (collisions between planet-sized bodies) that dominate the en d of accretion. Using numerical simulations of giant impacts\, I will show that the efficiency of atmospheric loss depends strongly on the surface c onditions on the colliding bodies (e.g.\, atmospheric pressure\, presence/ absence of an ocean). Understanding the complex feedbacks between the evol ution and survival of planetary atmospheres provides new insights into the origin of our atmosphere and ocean.\nSpeakers:\nDr Simon Lock (University of Bristol) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/bd473dfa-0a9c-4f96-ad64-d0d326c7b636/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Atmospheric loss in giant impacts: The effect of pre-impa ct surface conditions\; Research seminar with Dr Simon Lock - Dr Simon Loc k (University of Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Mapping mantle flow with seismic anisotropy: a seismo-geodynamics approach - Prof Ana Ferreira (UCL) DTSTART;VALUE=DATE-TIME:20231124T120000Z DTEND;VALUE=DATE-TIME:20231124T130000Z UID:https://talks.ox.ac.uk/talks/id/d60ab2e1-5037-48c4-b47c-b8d0153f9805/ DESCRIPTION:Seismic anisotropy provides key information to map the traject ories of mantle flow and understand the evolution of our planet. While the presence of anisotropy in the uppermost mantle is well established\, the existence and nature of anisotropy in the transition zone and uppermost lo wer mantle are still debated. Here we use three-dimensional global seismic tomography images based on a large dataset that is sensitive to this regi on to show the presence of anisotropy in the lower mantle beneath subducti on zones. We interpret the tomography images in terms of mantle flow using results from 3-D geodynamical models and mantle fabrics calculations. We then discuss three ongoing directions to enhance the imaging and interpret ation of mantle anisotropy via: (i) improved waveform modelling for indepe ndent model appraisal\; (ii) more integrated seismic and geodynamical anal yses\; and\, (iii) new data from a large-scale offshore passive experiment in the mid-Atlantic.\nSpeakers:\nProf Ana Ferreira (UCL) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/d60ab2e1-5037-48c4-b47c-b8d0153f9805/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Mapping mantle flow with seismic anisotropy: a seismo-geo dynamics approach - Prof Ana Ferreira (UCL) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Volatile metals in volcanic systems - Research seminar with Prof M arie Edmonds - Prof Marie Edmonds (Cambridge) DTSTART;VALUE=DATE-TIME:20231117T120000Z DTEND;VALUE=DATE-TIME:20231117T130000Z UID:https://talks.ox.ac.uk/talks/id/7b92436b-a4d0-42a8-b3f8-4e2e9cb780e1/ DESCRIPTION:Volcanic gases contain species such as carbon dioxide\, water and sulfur\, but also small but significant concentrations of volatile met als and metalloids\, such as copper\, selenium\, antimony. These elements may be toxic in large concentrations in our surface environment\, but they are also nutrients and critical components of life. Magmatic systems and volcanoes play an important role in cycling these elements from the interi or of our planet to the shallow crust\, atmosphere and oceans. In this tal k I will review the state of knowledge regarding the behaviour of these el ements in silicate melts and exsolved fluids\, based on measurements of vo lcanic gases\, glasses\, sulfides and fluid inclusions. I will discuss how the abundance and behaviour of these metals in volcanic and magmatic flu ids differs between tectonic settings (and why) and the factors maximising the flux of these species to the surface environment. These studies help us to interrogate geological records such as ice cores\, understand the fo rmation of critical metal deposits\, and understand better the links betwe en metal cycling and life.\nSpeakers:\nProf Marie Edmonds (Cambridge) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/7b92436b-a4d0-42a8-b3f8-4e2e9cb780e1/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Volatile metals in volcanic systems - Research seminar wi th Prof Marie Edmonds - Prof Marie Edmonds (Cambridge) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Towards a new understanding of the inorganic carbon budget in the Arctic - Research seminar with Dr Emily Stevenson - Dr Emily Stevenson (Un iversity of Cambridge) DTSTART;VALUE=DATE-TIME:20231110T120000Z DTEND;VALUE=DATE-TIME:20231110T130000Z UID:https://talks.ox.ac.uk/talks/id/a03cf782-9c15-4d1a-918d-a8af5440907a/ DESCRIPTION:Enhanced physical weathering in the Arctic through glacial ret reat\, permafrost thaw and collapse is exposing and mobilising vast amount s of finely-ground sediment to the agents of weathering. Elevated pyrite m ineral oxidation caused by the exposure of sulfide minerals in sedimentary lithologies can generate sulfuric acid which can weather freshly exposed carbonate minerals and release Carbon dioxide (CO2) to the atmosphere. In this talk I will present a high resolution and long term geochemical data set from a high Arctic River (Zackenberg River\, Northeast Greenland). Ele mental and isotopic measurements allow river water chemistry to be partiti oned between the different sources of acidity and mineral endmembers in or der to quantify the net CO2 fluxes from the Zackenberg river catchment\, a nd how these chemical weathering reactions have evolved daily\, seasonally and annually over the past 20 years.\nNet CO2 budget calculations show th at every year the Zackenberg River Catchment has resulted in a net CO2 flu x to the atmosphere\, the opposite of what is predicted via traditional si licate weathering calculations and theory. The total balance of CO2 releas e varies from year to year\, with some of the largest CO2 release fluxes a ssociated with the high erosion rates\, and large rainfall events. This sc enario could represent a small but plausible modern-day positive climate f eedback loop\, which is unaccounted for in coupled CO2-climate models.\nSp eakers:\nDr Emily Stevenson (University of Cambridge) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/a03cf782-9c15-4d1a-918d-a8af5440907a/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Towards a new understanding of the inorganic carbon budge t in the Arctic - Research seminar with Dr Emily Stevenson - Dr Emily Stev enson (University of Cambridge) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Rocky planets as the Lavosier-Lomonosov Bridge from the non-living to the living world - Research seminar with Prof Stephen Mojzsis - Prof S tephen Mojzsis (University of Colorado Boulder) DTSTART;VALUE=DATE-TIME:20231020T120000 DTEND;VALUE=DATE-TIME:20231020T130000 UID:https://talks.ox.ac.uk/talks/id/08335c09-1f52-4fec-b3ba-fbeaf3d0cea6/ DESCRIPTION:Life on Earth emerged at the interface of the planet’s geosp here\, hydrosphere and atmosphere. This setting serves as our basis for ho w biological systems originate on rocky planets. Often overlooked\, howeve r\, is the fact that a terrestrial-type planet’s chemical nature is ulti mately a product of the Galaxy’s long term evolution. Elemental abundanc es of the major rock-forming elements (e.g. Si\, Mg\, Fe) can be different for different stars and planets formed at different times in galactic his tory. These differences mean that we cannot expect small rocky exoplanets to be just like Earth. Furthermore\, age of the system dictates starting n uclide inventory from galactic chemical evolution\, and past\, present and future mantle and crust thermal regimes. A rocky planet’s bulk silicate mantle composition modulates the kind of atmosphere and hydrosphere it po ssesses. Hence\, the ingredients of a rocky planet are as important for it s potential to host life as proximity to the so-called habitable zone arou nd a star where liquid water is stable at the surface. To make sense of th ese variables\, a new trans-disciplinary approach is warranted that fuses the disciplines of Geology and Astronomy into what is here termed\, Geoast ronomy.\n\nRef. Mojzsis\, S.J. (2022) Geoastronomy: Rocky planets as the L avoisier-Lomonsov Bridge from the non-living to the living world. in Royal Society of Chemistry-Prebiotic Chemistry and Life’s Origin\, 21-76.\nSp eakers:\nProf Stephen Mojzsis (University of Colorado Boulder) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/08335c09-1f52-4fec-b3ba-fbeaf3d0cea6/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Rocky planets as the Lavosier-Lomonosov Bridge from the n on-living to the living world - Research seminar with Prof Stephen Mojzsis - Prof Stephen Mojzsis (University of Colorado Boulder) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Ready to Fail: The 2023 Turkiye earthquake disaster - Research sem inar with Dr Ekbal Hussain - Dr Ekbal Hussain (British Geological Survey) DTSTART;VALUE=DATE-TIME:20231013T120000 DTEND;VALUE=DATE-TIME:20231013T130000 UID:https://talks.ox.ac.uk/talks/id/1bd2fca0-a11c-4773-a4f1-372ddee51ae5/ DESCRIPTION:Globally\, two thirds of deaths arising from natural hazards i n recent decades were caused by geological hazards. But how and why do nat ural hazards turn into disasters? In this talk I will explore this questio n through the lens of one particularly troublesome hazard: earthquakes. We will focus on general themes but make specific references to the 2023 Tur kiye earthquake disaster. The death toll for a given earthquake magnitude will depend not only on geographic location\, but also the social vulnerab ility of communities and the quality of the building stock. But these are dynamic features of evolving societies\, which means earthquake risk varie s in time and space. This talk will compare and contrast global trends in earthquake fatalities and aim to extract common issues that exacerbate the impact of natural hazards\, and consider where and why these turn into di sasters.\nSpeakers:\nDr Ekbal Hussain (British Geological Survey) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/1bd2fca0-a11c-4773-a4f1-372ddee51ae5/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Ready to Fail: The 2023 Turkiye earthquake disaster - Res earch seminar with Dr Ekbal Hussain - Dr Ekbal Hussain (British Geological Survey) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Landscape evolution and the early Mars hydroclimate: constraints f rom paleolake and valley morphologies - Dr Gaia Stucky de Quay (MIT/Harvar d) DTSTART;VALUE=DATE-TIME:20231201T120000Z DTEND;VALUE=DATE-TIME:20231201T130000Z UID:https://talks.ox.ac.uk/talks/id/4862a6c0-76fb-4959-b140-7dca2c04be68/ DESCRIPTION:Fluvio-lacustrine features on the martian surface attest to a climate that was radically different in the past. Ubiquitous valley networ ks and paleolakes across Mars’ southern highlands suggest that long-live d precipitation may have persisted up to 3.7 billion years ago. However\, because climate models have difficulty sustaining a liquid hydrosphere at the surface\, it has been hypothesized that multiple cycles of runoff epis odes may have characterized the ancient martian climate. Despite the decad es-long accumulation of in situ and remote sensing data on surface water m odification features\, fundamental questions on the nature of Mars’ pale oclimate and its hydrological cycle remain: (1) How much rainfall and/or s nowmelt occurred during a given interval of favorable climate?\; and (2) H ow long did these runoff-producing episodes last? Here we combine measurem ents of 96 open- and closed-basin lakes with simple hydrological balances to constrain catchment-averaged precipitation over a given runoff episode. We include newly identified systems containing both open- and closed-basi n lakes—i.e.\, coupled systems—which provide fully bounded precipitati on estimates. We show that\, on average\, local precipitation was ≳4 m a nd ≲159 m\, and the climate was semi-arid or more humid in certain regio ns. We integrate these results with existing climate model data to quantit atively derive runoff episode duration\, which was likely between 100-10\, 000 yr and spatially variable. Finally\, we also investigate global erosio nal volumes for valleys associated to paleolakes to explore and define the limits of climate reconstruction on Mars. Importantly\, these spatio-temp oral hydroclimate constraints allow us to test paleoclimate model scenario s\, working towards bridging the gap between geological observations and c limate theory for early Mars.\nSpeakers:\nDr Gaia Stucky de Quay (MIT/Harv ard) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/4862a6c0-76fb-4959-b140-7dca2c04be68/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Landscape evolution and the early Mars hydroclimate: cons traints from paleolake and valley morphologies - Dr Gaia Stucky de Quay (M IT/Harvard) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Does the silicate Earth have a leaky bottom? - Research seminar wi th Prof Tim Elliott - Prof Tim Elliott (University of Bristol) DTSTART;VALUE=DATE-TIME:20231103T120000Z DTEND;VALUE=DATE-TIME:20231103T130000Z UID:https://talks.ox.ac.uk/talks/id/ab3d0ba7-9c22-4611-b8a1-e4294e8c94aa/ DESCRIPTION:Geodynamic models have long modelled plumes originating from t he bottom of the mantle. From this perspective\, hot-spot magmatism provid es a sample of the deepest mantle and potentially might carry evidence of on-going chemical exchange from core to mantle. Implicating protracted co re-mantle interaction from the geochemistry of hot-spot magmas has been a sporadically popular notion over the last fifty years. In the last decade\ , unradiogenic values of 182W/184W have been reported in some hot-spot lav as\, which provides perhaps the most convincing evidence of leakage from c ore to mantle. In this talk\, I will assess this idea against alternative theories to account for unradiogenic 182W/184W in oceanic basalts and expl ore its implications for the longer term evolution of the mantle.\nSpeaker s:\nProf Tim Elliott (University of Bristol) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/ab3d0ba7-9c22-4611-b8a1-e4294e8c94aa/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Does the silicate Earth have a leaky bottom? - Research s eminar with Prof Tim Elliott - Prof Tim Elliott (University of Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Active Rifting in the East African Rift System and Challenges in D isaster Risk Management - Prof Atalay Ayele (University of Addis Ababa) DTSTART;VALUE=DATE-TIME:20230616T120000 DTEND;VALUE=DATE-TIME:20230616T130000 UID:https://talks.ox.ac.uk/talks/id/56ae88bd-1b30-4f5a-b352-226cefcfa46d/ DESCRIPTION:The roughly 3000 km long East Africa Rift system (EARS) is one of the striking features of the African continent that captures all stage s of rift development from the most juvenile to nascent seafloor spreading in Okavango delta and Afar depression\, respectively. It provides a natur al laboratory for studying a fundamental\, and yet enigmatic\, component o f plate tectonics. A mechanism for rupturing thick\, cold\, continental li thosphere is not readily apparent in conventional models of mechanical str etching. Magma production weakens the plate and serve to localize strain\, thus better facilitating rifting. Studies of seismicity and volcanism pro vide insights into this problem and a variety of geophysical\, geochemical and geological studies can be used to better understand the role of the c rust and mantle in continental breakup. However\, observational data have limitations in the global south both in quality and density which poses co nstraints for detailed investigation and understanding of the rift process .\n\nPermanent seismic station distribution is sparse in the continent but some focused and episodic studies have been conducted using temporary br oad seismic networks in collaboration with overseas researchers. Earthquak es of magnitude 7.0 and above are observed in EARS from instrumentally rec orded seismicity (the 1910 Rukwa earthquake in Tanzania\, the 1990 earthqu ake in South Sudan and the 2006 Machase earthquake in Mozambique) which is a wakeup call for the fast growing construction industry in the region. I t is inferred that the EARS is more active than we think\, from recently r ecorded seismicity\, which requires collaborative efforts to enhance studi es in the region both to enhance basic science research and disaster risk management in the continent.\nSpeakers:\nProf Atalay Ayele (University of Addis Ababa) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/56ae88bd-1b30-4f5a-b352-226cefcfa46d/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Active Rifting in the East African Rift System and Challe nges in Disaster Risk Management - Prof Atalay Ayele (University of Addis Ababa) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Can geodesy shed light on the interplay between hydrology and the solid Earth? - Dr Kristel Chanard (IPGP\, Paris) DTSTART;VALUE=DATE-TIME:20230602T120000 DTEND;VALUE=DATE-TIME:20230602T130000 UID:https://talks.ox.ac.uk/talks/id/f29a5222-741a-4a1f-87cd-629df8d2b973/ DESCRIPTION:There is a long-standing interest in the interactions between hydrological processes and the deformation of the solid Earth\, including earthquakes. This talk will highlight recent advances in geodesy that allo w us to monitor the spatial and temporal changes in continental water stor age over seasonal to decadal time scales and how they deform the Earth. We will explore various implications of these observations\, including probi ng the Earth’s mechanical properties\, such as the mantle’s transient rheology and the hydromechanical properties of aquifers\, or advancing our understanding of the seismic cycle. These findings have significant impli cations for addressing pressing scientific and societal challenges\, inclu ding gaining insights into the physical processes associated with Earth de formation and the earthquake cycle\, and developing strategies for sustain able water resources management.\nSpeakers:\nDr Kristel Chanard (IPGP\, Pa ris) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/f29a5222-741a-4a1f-87cd-629df8d2b973/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Can geodesy shed light on the interplay between hydrology and the solid Earth? - Dr Kristel Chanard (IPGP\, Paris) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Skeletons in the closet: ethics\, law\, and politics in palaeontol ogy - Dr Nussaibah Raja Schoob (University of Erlangen-Nuremberg (Germany) ) DTSTART;VALUE=DATE-TIME:20230519T120000 DTEND;VALUE=DATE-TIME:20230519T130000 UID:https://talks.ox.ac.uk/talks/id/642d601d-8b3a-474b-8e30-32e7b62466b5/ DESCRIPTION:Palaeontology is unique among scientific disciplines in that i t thrives on the exchange of information across diverse communities\, both academic and non-academic. However\, palaeontological research does not a lways best serve these communities. A practice that is prevalent in palaeo ntology is “parachute science”\, referring to the practice whereby res earchers drop into\, collect data and leave without the involvement or int eraction with the local community. Put simply\, these parachuting palaeont ologists are benefitting from the resources of a country and often\, the e fforts of local people\, without giving anything back. Lack of paleontolog ical and scientific involvement with communities in the Global South may b e a remnant of colonial-era palaeontology. The history of natural science is inseparable from the history of European colonialism when local specime ns were brought to the homeland of the colonisers to be reposited and stud ied in museums for the sake of the “greater scientific good”. The cult ure of theft and plunder\, a legacy of colonialism perpetuates in palaeont ology\, even now. The drive for discovering the next new extraordinary fos sil can be linked to several ethical and legal issues\, where fossils are excavated without record and smuggled across borders to finally end up in collections across the world.\nSpeakers:\nDr Nussaibah Raja Schoob (Univer sity of Erlangen-Nuremberg (Germany)) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/642d601d-8b3a-474b-8e30-32e7b62466b5/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Skeletons in the closet: ethics\, law\, and politics in p alaeontology - Dr Nussaibah Raja Schoob (University of Erlangen-Nuremberg (Germany)) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Understanding the mechanisms behind global temperature change and oxygen rise over Earth history - Dr Ben Mills (Leeds) DTSTART;VALUE=DATE-TIME:20230526T120000 DTEND;VALUE=DATE-TIME:20230526T130000 UID:https://talks.ox.ac.uk/talks/id/f0f36500-d873-4352-8008-64c1c4936a34/ DESCRIPTION:A temperate and high-oxygen environment appears to be required for complex life. It is well understood that Earth's climate has broadly been stable over the planet's history\, but has oscillated between warmer and colder phases. In contrast to this\, the amount of oxygen in the atmos phere has risen from trace levels to become the second most abundant gas. Understanding why this has happened is fundamental to a range of scientifi c work in understanding our own past\, the future conditions on our planet \, and our likelihood of finding life elsewhere in the galaxy. I will intr oduce my group's work\, where we have built a new type of 'Earth Evolution ' computer model\, able to simulate the evolving Earth system in 3D over g eological time. We compare the model predictions to geological\, geochemic al and paleontological data in order to try to understand the key drivers beind global environmental change. Specifically\, we argue that temperatur e oscillations are controlled by several important linked processes and do not have a single key driver\, and we propose that oxygen rise over Earth history is dependent on the build-up of carbon in Earth's crust in the fo rm of carbonate minerals.\nSpeakers:\nDr Ben Mills (Leeds) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/f0f36500-d873-4352-8008-64c1c4936a34/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Understanding the mechanisms behind global temperature ch ange and oxygen rise over Earth history - Dr Ben Mills (Leeds) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Plume-related diamond formation in the central Kaapvaal craton - D r Karen Smit (University of the Witwatersrand\, South Africa) DTSTART;VALUE=DATE-TIME:20230512T120000 DTEND;VALUE=DATE-TIME:20230512T130000 UID:https://talks.ox.ac.uk/talks/id/318352b5-23bb-4f21-a67d-f477402fba73/ DESCRIPTION:Despite its long-term lithospheric stability\, the Kaapvaal cr aton hosts several large igneous provinces (LIPs) that generated large amo unts of magma over short time intervals during the Archaean and Proterozoi c. These include the Ventersdorp at 2791–2683 Ma\, the Hekpoort at 2247 –2224 Ma\, the Bushveld at 2056–2054 Ma\, and the Umkondo at 1112–11 06 Ma.\n\nIn some cratons\, plume magmatism and heating in the lithospheri c mantle is destructive to diamonds. For example\, in the Superior craton plume magmatism and heating related to the 1.1 Ga Midcontinent Rift caused lithosphere thinning below the Attawapiskat region with a significantly n arrower ‘diamond-window’ (Smit et al.\, 2014\, Stachel et al.\, 2018). In the Slave craton\, the 1.27 Ga Mackenzie Plume thinned the lithospheri c mantle to only 80 km\, which is not sufficient for diamond stability (Li u et al.\, 2021). In contrast\, the Kaapvaal craton hosts diamonds that fo rmed during times of plume magmatism. For example\, 1930 ± 40 Ma lherzoli tic diamonds from Cullinan mine formed within 100 My of the Bushveld and l ikely represent plume-related heating in the lithospheric mantle and melt mobilisation in peridotite (Richardson et al.\, 1993)\n\nNew Sm-Nd isotopi c data on garnet and clinopyroxene inclusions in diamonds from the Voorspo ed mine reveal two distinct age populations. For the peridotitic suite (28 inclusions) diamond formation occurred at 2736 ± 27.4 Ma\, while inclusi ons (n = 16) from eclogitic diamonds define a 2196 ± 61 Ma Sm-Nd isochron . Growth of these diamonds correlates with the emplacement of plume-relate d Ventersdorp and Hekpoort LIPs\, at ~2.7 Ga and 2.2 Ga\, respectively.\n\ nGeothermobarometry of Voorspoed diamonds and their mineral inclusions sho ws that at the time of Ventersdorp and Hekpoort plume magmatism\, the Kaap vaal lithospheric mantle experienced high temperatures >1250–1300 °C\, yet there was preservation of a thick lithospheric mantle with conditions favourable for diamond growth. Additionally\, peridotites from across the Kimberley and Witwatersrand blocks have a mode of osmium TRD ages between 2.8 and 2.4 Ga (e.g.\, Carlson et al.\, 1999\, Pearson et al.\, 2004)\, li kely reflecting melt depletion and lithospheric mantle creation due to the Ventersdorp event. In the lower crust\, Mesoarchaean granulite xenoliths also preserve ultra-high temperature metamorphic assemblages (Schmitz and Bowring\, 2003).\n\nTo reconcile thermal reactivation in the crust with th e preservation of coeval diamond-favourable conditions in the mantle\, one plausible model is that crustal extension was asymmetric\, e.g.\, the sim ple-shear model from Wernicke (1985)\, and modelling in Zwaan et al. (2022 ). This is consistent with the proposed Ventersdorp plume impingement site being below the present-day eastern Bushveld (Humbert et al.\, 2019)\, wh ereas the voluminous surface volcanism extends much further west of the Co lesberg magnetic lineament\nSpeakers:\nDr Karen Smit (University of the Wi twatersrand\, South Africa) LOCATION:Department of Earth Sciences (via zoom link: https://zoom.us/j/96 527177371)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/318352b5-23bb-4f21-a67d-f477402fba73/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Plume-related diamond formation in the central Kaapvaal c raton - Dr Karen Smit (University of the Witwatersrand\, South Africa) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Carbon Cycling at the Dawn of the Cenozoic - Dr Michael Henehan (B ristol) DTSTART;VALUE=DATE-TIME:20230505T120000 DTEND;VALUE=DATE-TIME:20230505T130000 UID:https://talks.ox.ac.uk/talks/id/7491d524-9ec8-465f-b457-dc64c888adcc/ DESCRIPTION:The Paleocene – the first epoch of the Cenozoic (66–56 Ma) – is an intriguing\, and often puzzling\, time interval sandwiched betw een the charismatic events of the Paleocene-Eocene Thermal Maximum (PETM) and Cretaceous-Palaeogene (K-Pg) boundary. The epoch is relatively underst udied\, but spans numerous notable climatic and biogeochemical phenomena. In the oceans\, calcifying plankton communities had to gradually recover a fter the K-Pg bolide impact\, after which benthic marine carbonate δ13C v alues record one of the largest positive excursions in of the last 100 Myr 1 in the form of the Paleocene Carbon Isotope Maximum. On land\, an as-yet -unexplained extreme step-change in global weathering regime is indicated by marine carbonate δ7Li values2. More generally\, despite benthic forami niferal oxygen isotopes that suggest a greenhouse climate much warmer than today3\, scant proxy estimates of atmospheric CO2 in the Paleocene mostly indicate low CO2 levels more similar to those seen during the relatively colder late Neogene4.\n\nIn this talk\, I will summarise some of the recen t headway we have made in understanding geochemical cycling and ocean chem istry at the dawn of the Cenozoic\, immediately after the K-Pg impact. Fol lowing this\, I will present new benthic and planktic foraminiferal boron and lithium isotope data that address some of the outstanding puzzles of t his formative period for the Cenozoic carbon cycle. Our new\, higher boron -derived atmospheric CO2 estimates for this interval resolve some of the a pparently anomalous3 behaviour of the Paleocene climate system\, and in do ing so provide a better understanding of the climatic baseline to the PETM .\n\nAt the end of the talk\, I’ll introduce future research plans at Br istol – specifically my 5-year ERC Consolidator Grant (now a UKRI Fronti er Research Grant) PETRARCH\, with the help of which I hope to push some o f these quantitative proxy approaches back to the peak warmth of the Creta ceous period to understand what it takes to trigger a global Ocean Anoxic Event.\nSpeakers:\nDr Michael Henehan (Bristol) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/7491d524-9ec8-465f-b457-dc64c888adcc/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Carbon Cycling at the Dawn of the Cenozoic - Dr Michael H enehan (Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Towards an understanding of the earthquake process for natural and induced seismicity - Prof Daniel Faulkner (University of Liverpool) DTSTART;VALUE=DATE-TIME:20230224T120000Z DTEND;VALUE=DATE-TIME:20230224T130000Z UID:https://talks.ox.ac.uk/talks/id/b3478a32-90d3-4ea6-b0ae-b9e81f187eda/ DESCRIPTION:Natural seismicity produces earthquakes that result in signifi cant loss of life and billions of dollars of damage each year. Moreover\, induced earthquakes from subsurface fluid injection endanger industries\, such as carbon capture and storage\, and geothermal\, that are vital in ou r transition to a greener future. In this talk\, the number and size of ea rthquakes that result from a fluid injection project in the Horn River Bas in in Canada are linked to laboratory measurements of frictional stability \, providing the potential to forecast induced seismicity before injection even starts. Following from this\, laboratory measurements relating to ea rthquake nucleation and rupture propagation are incorporated into large-sc ale finite fault models that can produce sequences of earthquakes and help us understand why we get different number of small to large earthquakes. The results suggest that large faults\, such as the southern San Andreas F ault in California\, that today have very few earthquakes on them\, potent ially only rupture in large earthquake events and that the stress on these faults is very low.\nSpeakers:\nProf Daniel Faulkner (University of Liver pool) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/b3478a32-90d3-4ea6-b0ae-b9e81f187eda/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Towards an understanding of the earthquake process for na tural and induced seismicity - Prof Daniel Faulkner (University of Liverpo ol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth formation in the laboratory: core-mantle differentiation aft er giant impacts - Dr Maylis Landeau (IPGP & Université Paris Cité) DTSTART;VALUE=DATE-TIME:20230310T120000Z DTEND;VALUE=DATE-TIME:20230310T130000Z UID:https://talks.ox.ac.uk/talks/id/a6fa6b48-a76f-40b4-bc16-ce34ea94b3a3/ DESCRIPTION:The formation of the Earth set the initial temperature and com position for its later evolution. The onset of plate tectonics and the gen eration of Earth’s magnetic field both depend on these initial condition s. Based on isotopic and geochemical observations\, we know that the metal lic core separated from the mantle silicates during Earth formation\, when high-energy planetary collisions were building up its mass. However\, we do not know how mixed metal and silicates were during\, and after\, each c ollision. Their chemical equilibration\, and the resulting composition of the core and the mantle\, depend on this mixing.\n\nWe investigate the flu id dynamics of planetary collisions in laboratory experiments. From our fi ndings\, we infer the efficiency of metal-silicate mixing within the formi ng Earth. Our results also indicate that the stratification in the present -day Earth’s core could be a vestige of the giant impact that formed the Moon.\nSpeakers:\nDr Maylis Landeau (IPGP & Université Paris Cité) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/a6fa6b48-a76f-40b4-bc16-ce34ea94b3a3/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth formation in the laboratory: core-mantle differenti ation after giant impacts - Dr Maylis Landeau (IPGP & Université Paris Ci té) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Filling in the Map: The space-time geography of Arctic Ocean mixin g and why it matters - Prof Stephanie Waterman (University of British Colu mbia\, Canada) DTSTART;VALUE=DATE-TIME:20230203T120000Z DTEND;VALUE=DATE-TIME:20230203T130000Z UID:https://talks.ox.ac.uk/talks/id/ed073d22-cdf5-4cb6-be39-05263588cbd3/ DESCRIPTION:The rates and mechanisms of ocean mixing are important control s on how the oceans function\; yet\, our understanding of mixing in the oc ean is significantly limited by complex variability in mixing rates and pr ocesses\, and by a scarcity of direct observations. In the Arctic Ocean\, the challenges are significant: mixing measurements are especially sparse and latitude\, ice\, and stratification make the mixing environment unique . In this talk\, I’ll discuss various ways we are mapping Arctic Ocean m ixing rates and deriving insights into what sets mixing space-time geograp hy using pan-Arctic measurements from a variety of autonomous instrument p latforms and the archived data record. I’ll also show results from our e xperiments with realistic ocean models to argue that this map matters both to our understanding of Arctic Ocean functioning and our ability to make robust predictions of future climate change.\nSpeakers:\nProf Stephanie Wa terman (University of British Columbia\, Canada) LOCATION:Department of Earth Sciences\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/ed073d22-cdf5-4cb6-be39-05263588cbd3/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Filling in the Map: The space-time geography of Arctic Oc ean mixing and why it matters - Prof Stephanie Waterman (University of Bri tish Columbia\, Canada) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth-Life coevolution: trace elements at the interface between ge osphere and biosphere through time - Prof Donato Giovannelli (University of Naples “Federico II”) DTSTART;VALUE=DATE-TIME:20230127T120000Z DTEND;VALUE=DATE-TIME:20230127T130000Z UID:https://talks.ox.ac.uk/talks/id/b4521b70-f68b-483d-81af-7feb1eaab913/ DESCRIPTION:Earth’s geosphere and biosphere have coevolved over time\, i nfluencing each other’s stability and keeping our planet habitable over the last ~4 billion years. Biogeochemical cycles play a key role in contro lling this interaction\, connecting long-term geological cycles and the mu ch faster evolution of the Earth’s outer biologically dominated envelope s. A small set of microbial-encoded proteins containing redox-sensitive tr ansition metals as their core catalytic center carry out the majority of t he key biogeochemical reactions. Metals such as Fe\, Co\, Ni\, Zn\, Mo\, W \, V\, and Cu are used in these proteins to access diverse redox couples a s a function of the changing planetary availability of these elements over time. Despite the importance of this process\, the relationship between m etal availability and metabolism evolution and diversity has not been inve stigated in detail. Here\, we will present recent data from field and labo ratory experiments elucidating the impact of transition metal availability on microbial functional diversity\, and its implications for the emergenc e and evolution of life on Earth\, while discussing the implications of th ese findings for the search for life in the Universe.\nSpeakers:\nProf Don ato Giovannelli (University of Naples “Federico II”) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/b4521b70-f68b-483d-81af-7feb1eaab913/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth-Life coevolution: trace elements at the interface b etween geosphere and biosphere through time - Prof Donato Giovannelli (Un iversity of Naples “Federico II”) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The origin of water in chondritic meteorites and the Earth - Dr. C onel Alexander (Carnegie Institution of Washington) DTSTART;VALUE=DATE-TIME:20230303T120000Z DTEND;VALUE=DATE-TIME:20230303T130000Z UID:https://talks.ox.ac.uk/talks/id/44a872d8-9964-4ee2-9125-6ebcc9f0a8be/ DESCRIPTION:The chondritic meteorites formed between ~2 Myr and ~4 Myr aft er Solar System formation and provide records of processes that were opera ting in the solar protoplanetary disk before and during that time. However \, the fidelity of that record varies because all chondrites were subject to internal heating by the decay of short-lived radionuclides. This intern al heating drove aqueous and metamorphic lithification processes that conv erted unconsolidated ‘sediments’ into rocks that could survive impact excavation from their asteroidal parent bodies and atmospheric entry. The effects of lithification can be reduced to some extent by studying the lea st altered meteorites\, but water and organics have been modified even in these samples. Water\, for instance\, was involved in the oxidation of Fe- metal. If the H2 that was generated and lost approached isotopic equilibri um with the water\, it was probably very deuterium-(D)-poor as is seen in low temperature serpentines on Earth. As a result\, the remaining water be came increasingly D-rich. The water was also involved in the alteration of silicates to hydrated minerals. Indeed\, it is the H2O/OH in these hydrat ed minerals that preserves a record of the water isotopic compositions\, a lbeit modified by fluid-silicate H and O isotopic exchange. Any ice that m ay once have been present will have sublimed away in interplanetary space before atmospheric entry. It also seems likely that there was H isotopic e xchange between the water and D-rich organic matter during lithification. Various approaches can be used to try to ’see’ through the parent body modification. It seems that the carbonaceous chondrites\, which are gener ally thought to have formed beyond the orbit of Jupiter\, accreted ices (C O/CO2– and NH3/HCN-bearing) and refractory organic matter that resembled in many ways those in comets. Both the water and organics in comets and c hondrites may have at least partial interstellar heritages as indicated by their high D/H ratios relative to the solar ratio. However\, the D/H of t he water and\, perhaps\, the organics are lower in chondrites than comets\ , probably because of heating in the disk prior to accretion. Counterintui tively\, the water accreted by the chondrites\, which are thought to have formed in the warmer terrestrial planet region sunward of Jupiter\, may ha ve had higher D/H than in the carbonaceous chondrites\, but this remains c ontroversial. The bulk of the Earth’s building blocks were probably earl y-formed (<2 Myr) planetesimals that had melted and differentiated due to the abundance of short-lived radioactive heat sources. Our measurements of the silicate mantles of such objects\, achondrites\, indicates that they contain very little H. Hence\, the Earth’s H\, along with C\, N\, noble gases and other highly volatile elements\, was probably largely delivered by a few weight percent of planetesimals that resembled CI/CM carbonaceous chondrites and was accreted before the Moon-forming impact. However\, nob le gases require small contributions from comets and solar gas. There is a lso some noble gas evidence that\, counter to the current paradigm\, most volatiles were neither degassed from nor equilibrated with a global magma ocean following formation of the Moon\, or that impact induced blow off of early atmospheres can account for the non-chondritic BSE relative abundan ces of volatiles elements like N.\nSpeakers:\nDr. Conel Alexander (Carnegi e Institution of Washington) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/44a872d8-9964-4ee2-9125-6ebcc9f0a8be/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The origin of water in chondritic meteorites and the Eart h - Dr. Conel Alexander (Carnegie Institution of Washington) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The operation of the terrestrial methane cycle during the Cenozoic and Mesozoic\, including hyperthermals such as the PETM and T-OAE - Dr Da vid Naafs (Bristol) DTSTART;VALUE=DATE-TIME:20221028T120000 DTEND;VALUE=DATE-TIME:20221028T130000 UID:https://talks.ox.ac.uk/talks/id/a486a581-31d4-4c2e-97b9-1a0b56b49f01/ DESCRIPTION:The terrestrial realm is the largest natural source of methane to Earth’s atmosphere\, where this powerful greenhouse gas influences E arth’s radiative budget. The terrestrial methane cycle is therefore a ke y biologically mediated process with the flux of methane to the atmosphere ultimately depending on the balance between methanogens that produce meth ane and methanotrophs that consume methane in wetlands and lakes. However\ , these processes and hence the operation of the terrestrial methane cycle in the geological past are poorly constrained. \n \nTo address this probl em\, I will present novel biomarker data that record the relative contribu tion of methanotrophs to the bacterial pool in a large number of ancient w etlands and lakes. I will use a unique dataset that consist of 100s of sam ples from across the world and which span most of the Cenozoic\, as well a s Toarcian OAE. The aim is to explore the past operation of the terrestria l methane cycle\, including during periods of rapid environmental change. \n \nThe data show that the contribution of methanotrophs to the terrestri al bacterial pool has been remarkable stable through time\, including acro ss major climatic events like the K/Pg boundary\, the Eocene – Oligocene transition\, and the mid-Miocene climatic optimum. These results indicate that the terrestrial methane cycle is robust to long-term climatic pertur bations and does not operate fundamentally different during greenhouse per iods. However\, during transient warming events\, e.g. the Paleocene Eocen e Thermal Maximum (PETM)\, the T-OAE\, etc\, the data indicate a significa nt perturbation of the terrestrial methane cycle. This means that transien t warming events have the potential to destabilize this key biogeochemical cycle\, which might have implications for how the terrestrial methane cyc le will respond to anthropogenic climate change. \n\nSpeakers:\nDr David N aafs (Bristol) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/a486a581-31d4-4c2e-97b9-1a0b56b49f01/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The operation of the terrestrial methane cycle during the Cenozoic and Mesozoic\, including hyperthermals such as the PETM and T-OA E - Dr David Naafs (Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Battery metals: Formation and the race to Net Zero - Dr Nick Gardi ner (St Andrew’s) DTSTART;VALUE=DATE-TIME:20221202T120000Z DTEND;VALUE=DATE-TIME:20221202T130000Z UID:https://talks.ox.ac.uk/talks/id/c9268395-be30-4ef7-bb66-ed00d40c9415/ DESCRIPTION:The transition to a renewable energy platform for the generati on\, transmission\, and storage of electricity\, requires a sufficient sup ply of key metals\, in particular the so-called “battery metals” tin\, lithium\, tungsten\, and tantalum. These metals are primarily sourced fro m magmatic-hydrothermal deposits\, which form when mineralising fluids exs olve from evolved\, volatile-saturated magmas. Here\, we show how geochemi cal microanalysis of accessory minerals can help shed light on the process es of crustal melting and of fractional crystallisation\, which together l ead to mineralization\, and how such a bottom-up approach may help us buil d better models for the formation of these deposits. We also discuss how i n a global mining context these battery metals are relatively small-scale\ , with a fragile supply pipeline\, and by taking the example of tin in the 2000’s discuss the current rush for lithium. \nSpeakers:\nDr Nick Gardi ner (St Andrew’s) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/c9268395-be30-4ef7-bb66-ed00d40c9415/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Battery metals: Formation and the race to Net Zero - Dr N ick Gardiner (St Andrew’s) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The Moon as an archive of collisional processes in the Solar Syste m: New Views from Apollo samples and lunar meteorites - Prof Katie Joy (Ma nchester) DTSTART;VALUE=DATE-TIME:20221104T120000Z DTEND;VALUE=DATE-TIME:20221104T130000Z UID:https://talks.ox.ac.uk/talks/id/9717b586-b21f-4a44-98ec-0a8da2365bdc/ DESCRIPTION:The Moon is an archive of impact cratering in the Solar System throughout the past 4.5 billion years. All of the Moon's large impact bas ins were formed between ~4.5 Ga and ~3.8 Ga\, however\, the duration and m agnitude of basin-formation is still currently not well known and the luna r impact record is controversial. This talk will give an overview of the t opic\, and discuss how new chemical and mineralogical analysis of Apollo s amples has provided insights to the types of impactors that were striking the Moon\, and how the lunar meteorite sample collection is revealing abou t the timing of lunar impact events.\nSpeakers:\nProf Katie Joy (Mancheste r) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/9717b586-b21f-4a44-98ec-0a8da2365bdc/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The Moon as an archive of collisional processes in the So lar System: New Views from Apollo samples and lunar meteorites - Prof Kati e Joy (Manchester) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Tracking variations in volcano construction and lithospheric flexu re along the Hawaiian-Emperor Seamount Chain - Prof Robert A. Dunn (Univer sity of Hawaii) DTSTART;VALUE=DATE-TIME:20221021T120000 DTEND;VALUE=DATE-TIME:20221021T130000 UID:https://talks.ox.ac.uk/talks/id/eef93e0a-44ca-44e7-944c-cebbd08a5cce/ DESCRIPTION:The Hawaiian-Emperor seamount chain is one the most prominent examples of a volcanic chain on the surface of the Earth\, and has long be en considered a hotspot track generated by the motion of the Pacific plate over a deep mantle plume. As individual volcanoes of the chain grow\, th ey apply a downward load on the seafloor and progressively deform the lith osphere. The resulting flexure is manifest in the deep bathymetric depress ion that flanks the volcanic chain. A key aspect that impacts plate loadi ng and rheological models of the lithosphere is the distribution of materi al added to the crust by magmatic activity. Previous studies suggested a r ange of possibilities\, from volcanic construction being confined to the r egion above the oceanic crust\, to some new material added within the crus t\, to some material “underplated” to the bottom of the crust. To inve stigate these and other issues\, a set of marine geophysical field studies were carried out across the Emperor and Hawaiian Ridges. Seismic images from three lines that cross the volcanic chain reveal the amount of new ma terial added to the plate\, the internal structure of the volcanoes and un derlying lithosphere\, the thickness of erosional material in the surround ing moats\, and the shape and degree of flexure of the lithosphere. The da ta allow us to compare plate loading and flexure for a load emplaced at a time when the plate was relatively young (Emperor Ridge) to a time when th e plate was relatively old (the Hawaiian Ridge) and will lead to better ag e-dependent loading and response models for oceanic lithosphere. \n\n\nSpe akers:\nProf Robert A. Dunn (University of Hawaii) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/eef93e0a-44ca-44e7-944c-cebbd08a5cce/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Tracking variations in volcano construction and lithosphe ric flexure along the Hawaiian-Emperor Seamount Chain - Prof Robert A. Dun n (University of Hawaii) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The uneven ice loss from the Greenland ice sheet: a study of fjord -scale fluxes - Dr Nanna B. Karlsson (GEUS) DTSTART;VALUE=DATE-TIME:20221014T120000 DTEND;VALUE=DATE-TIME:20221014T130000 UID:https://talks.ox.ac.uk/talks/id/2c8ef721-4f9a-4200-812c-21a19c36cad2/ DESCRIPTION:For over a decade\, the Geological Survey of Denmark and Green land has monitored the Greenland ice sheet to get accurate insights into t he loss of ice. Such insights are crucial if we are to predict future chan ges in the ice sheet and their impact on sea-level rise. As the ice sheet loses mass\, the flux of freshwater to the fjords increases thereby affect ing local ecosystems and marine life\, and ultimately local communities. I n this talk\, I will show how different processes control the freshwater f lux for different fjords\, and how our results enable us to quantify the d ominant freshwater term and the seasonality of the freshwater input from g lacier to glacier. Finally\, I will share my latest fieldwork experiences and insights from our most recent monitoring programme that aims to constr ain the snowfall in the interior of the ice sheet.\n\nIn addition\, I will briefly present results from an ongoing study aiming to map the gender ba lance of the geosciences in Denmark. Our findings show gendered difference s in opportunities and networks for all career stages but especially for e arly-career researchers.\nSpeakers:\nDr Nanna B. Karlsson (GEUS) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/2c8ef721-4f9a-4200-812c-21a19c36cad2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The uneven ice loss from the Greenland ice sheet: a study of fjord-scale fluxes - Dr Nanna B. Karlsson (GEUS) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Down to the deep – ocean biology’s role in the carbon cycle - Prof Stephanie Henson (National Oceanography Centre) DTSTART;VALUE=DATE-TIME:20221118T120000Z DTEND;VALUE=DATE-TIME:20221118T130000Z UID:https://talks.ox.ac.uk/talks/id/a60f7220-2694-4798-a50e-ed6089cabaf2/ DESCRIPTION:The biological carbon pump is a series of processes that trans fers organic carbon from the surface ocean into the deep ocean. Without i t\, atmospheric CO2 levels would be ~ 50 % higher than they already are. Despite its importance\, we currently struggle to understand how the stren gth and efficiency of the biological carbon pump vary over time – whethe r on scales of days\, seasons or years. This makes it difficult to observ e\, and therefore model the pump\, so our knowledge of how this important component of the global carbon cycle might respond to climate change is po or. In this talk I’ll present recent progress on using autonomous vehic les to quantify variability in the biological carbon pump\, discuss the cu rrent limitations in our understanding of the pump\, and the implications of those knowledge gaps for robust modelling of the current and future pum p.\nSpeakers:\nProf Stephanie Henson (National Oceanography Centre) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/a60f7220-2694-4798-a50e-ed6089cabaf2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Down to the deep – ocean biology’s role in the carbon cycle - Prof Stephanie Henson (National Oceanography Centre) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Plan A+: How stratospheric aerosol geoengineering could play a rol e in climate policy - Dr Peter Irvine (UCL) DTSTART;VALUE=DATE-TIME:20221111T120000Z DTEND;VALUE=DATE-TIME:20221111T130000Z UID:https://talks.ox.ac.uk/talks/id/e56ebe77-a52d-49b5-b93d-78badd0b5244/ DESCRIPTION:In this talk\, Dr. Peter Irvine (UCL\, Earth sciences) will in troduce the idea of Stratospheric Aerosol Injection (SA) geoengineering\, a proposal that aims to mimic the cooling effect of major volcanic eruptio ns\, and he will explain the role it could play in climate policy. His tal k will address the feasibility\, side-effects and potential of SAI as a me ans of reducing the risks of climate change\, and the broader concerns aro und this idea. He will also explain that while there's a risk that it coul d undermine the motivation to tackle anthropogenic emissions of CO2\, ther e are reasons to believe it might actually make it easier to address our i mpact on the carbon cycle.\nSpeakers:\nDr Peter Irvine (UCL) LOCATION:Department of Earth Sciences (Lecture Theatre)\, South Parks Road OX1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/e56ebe77-a52d-49b5-b93d-78badd0b5244/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Plan A+: How stratospheric aerosol geoengineering could p lay a role in climate policy - Dr Peter Irvine (UCL) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Modeling ice stream dynamics: a tale of theory\, numerical models\ , and observations - Dr Elisa Mantelli (University of Tasmania) DTSTART;VALUE=DATE-TIME:20220610T120000 DTEND;VALUE=DATE-TIME:20220610T130000 UID:https://talks.ox.ac.uk/talks/id/9a65df9e-5ddc-41b3-a6f1-f55eea333cb0/ DESCRIPTION:Ice streams are river-like corridors of fast flowing ice that account for the vast majority of ice discharge to the ocean in continental ice sheets. Their most outstanding feature is that they can appear sponta neously within a slowly moving ice sheet\, self-organize in evenly spaced patterns\, and switch on and off over time. Yet\, a full explanation of ic e stream formation and evolution is one of the longest standing open probl ems in glaciology. This knowledge gap has precluded fundamental investigat ions on the role of ice streams in driving ice sheet change\, and also cas ts doubt on the ability of state-of-the-art ice sheet simulation codes to project future sea levels. In this talk\, I strip away much of the sophist ication involved in “operational” ice sheet models to look at the ingr edients necessary to capture ice stream dynamics in minimal continuum mode ls. I first identify fundamental flaws in the established theory of slidin g initiation\, to show instead how a region of subtemperate sliding (i.e.\ , where sliding occurs below the melting point and sliding speeds are lim ited by the need to maintain the basal energy budget in balance) is essent ial to enable the onset of fast\, sliding-dominated\, ice stream flow. Nex t\, I move on to outlining how ice streams may emerge spontaneously out of an otherwise uniform ice sheet as a result of a newly identified instabil ity of subtemperate regions. Last\, I discuss how the pattern of englacial deformation in the onset region of the Institute Ice Stream (West Antarc tica) is consistent with an extended region of sliding initiation\, thus l ending support to the theoretical findings discussed above.\nSpeakers:\nDr Elisa Mantelli (University of Tasmania) LOCATION:Venue to be announced TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/9a65df9e-5ddc-41b3-a6f1-f55eea333cb0/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Modeling ice stream dynamics: a tale of theory\, numerica l models\, and observations - Dr Elisa Mantelli (University of Tasmania) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:VESIcal: An open-source thermodynamic model engine for mixed volat ile (H2O-CO2) solubility in silicate melts - Dr Kayla Iacovino (NASA) DTSTART;VALUE=DATE-TIME:20220520T150000 DTEND;VALUE=DATE-TIME:20220520T160000 UID:https://talks.ox.ac.uk/talks/id/3d4ae4c8-89be-4cea-8d02-a4aba5b3c731/ DESCRIPTION:Thermodynamic modeling has been the backbone of interpreting g eologic data and modelling geologic systems for decades. However\, more re cent advancements in computational capabilities and a marked increase in r esearchers' accessibility to computing tools has outpaced the functionalit y and extensibility of currently available modeling tools. VESIcal is the first comprehensive modelling tool for H2O\, CO2\, and mixed (H2O-CO2) sol ubility in silicate melts. VESIcal provides a thermodynamic framework that : a) allows users access to all commonly used models\, including easy inte rcomparison between models\; b) provides universal functionality for all m odels (e.g.\, functions for calculating saturation pressures\, degassing p aths\, etc.)\; c) can process large datasets (1\,000's of samples) automat ically\; d) outputs computed data into an excel spreadsheet for simple pos t-modelling analysis\; e) integrates advanced plotting capabilities direct ly within the tool\; and f) provides all of these within the framework of a python library\, making the tool extensible by the user and allowing any of the model functions to be incorporated into any other code capable of calling python.\n \nVESIcal is the first substantive cog in a broader visi on on the future of thermodynamic modeling of volatiles in magmatic system s. In this talk\, I will discuss this vision\, describe how VESIcal is the first large step toward meeting some ambitious goals\, and demonstrate th e power of VESIcal by performing some modeling in real time.\n\nSpeakers:\ nDr Kayla Iacovino (NASA) LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/3d4ae4c8-89be-4cea-8d02-a4aba5b3c731/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:VESIcal: An open-source thermodynamic model engine for mi xed volatile (H2O-CO2) solubility in silicate melts - Dr Kayla Iacovino (N ASA) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Iron-Sulfur Chemistry on Earth\, Mars and Venus: Implications for the origins and evolution of life in alien environments - Dr. Paul Rimmer (Cambridge) DTSTART;VALUE=DATE-TIME:20220429T120000 DTEND;VALUE=DATE-TIME:20220429T130000 UID:https://talks.ox.ac.uk/talks/id/293c6a5d-b96c-4e48-a7ff-2b46f71e5889/ DESCRIPTION:I will give a review of iron-sulfur chemistry in origins and e arly evolution of life\, starting with the work of Günter Wächtershäuse r and discussing the role of this proto-metabolic chemistry in underwater and surface hydrothermal vents. I will then present the cyanosulfidic and carboxysulfitic chemical scenarios developed by the Sutherland group and t alk about how this chemistry may help constrain where life can originate o n exoplanets and what chemistry to look for in Jezero Crater on Mars. I wi ll conclude with an unusual application of this chemistry to the clouds of Venus. Though it has nothing directly to do with life or its origins\, th is same chemistry may occur in the clouds of Venus to provide a very diffe rent set of products\, that may explain two long-standing mysteries about the chemical and optical properties of Venus’s clouds.\nSpeakers:\nDr. P aul Rimmer (Cambridge) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/293c6a5d-b96c-4e48-a7ff-2b46f71e5889/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Iron-Sulfur Chemistry on Earth\, Mars and Venus: Implicat ions for the origins and evolution of life in alien environments - Dr. Pau l Rimmer (Cambridge) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth Sciences Departmental research seminar with Dr Dan Frost - D r Dan Frost (University of Bayreuth) DTSTART;VALUE=DATE-TIME:20220617T120000 DTEND;VALUE=DATE-TIME:20220617T130000 UID:https://talks.ox.ac.uk/talks/id/4bf86c8b-a92c-4267-935a-ef4fe4c86ad2/ DESCRIPTION:\nSpeakers:\nDr Dan Frost (University of Bayreuth) LOCATION:Venue to be announced TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/4bf86c8b-a92c-4267-935a-ef4fe4c86ad2/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth Sciences Departmental research seminar with Dr Dan Frost - Dr Dan Frost (University of Bayreuth) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The deep biosphere: What lies beneath and why we should care - Dr Sophie Nixon (Manchester) DTSTART;VALUE=DATE-TIME:20220527T120000 DTEND;VALUE=DATE-TIME:20220527T130000 UID:https://talks.ox.ac.uk/talks/id/15a2d01c-db49-4fc4-964e-a83475866d34/ DESCRIPTION:The deep subsurface harbours the unseen majority of microbial diversity on Earth\, and a significant proportion of the planet’s biomas s. Understanding how life operates in these extreme environments highlight s the roles these microbes play in biogeochemical cycles of global signifi cance\, such as the carbon cycle. Such knowledge also helps to define the limits to life on Earth. However\, until recently little was known about t he diversity and function of microbial life in the deep biosphere. With th e recent advent of affordable sequencing technologies and ever sophisticat ed tools to unpick the genetic code\, we now know that the deep subsurface harbours an active and highly diverse biosphere. In this talk I will pre sent data from subsurface environments that highlight the diversity of dee p life\, and its contributions to biogeochemical cycling. Examples will in clude evidence for an active carbon- and sulfur-cycling microbial communit y in a deep borehole in Greenland\, a novel genus of bacteria recovered fr om a 2.5 km deep shale gas well\, and a glimpse of the microbial life deep beneath our feet in the North of England. With these examples I will demo nstrate the power of cutting-edge genomic tools for uncovering the ‘rule s of life’ in the subsurface\, and highlight the significant potential t o put subsurface microorganisms to work for the good of the environment an d society.\nSpeakers:\nDr Sophie Nixon (Manchester) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/15a2d01c-db49-4fc4-964e-a83475866d34/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The deep biosphere: What lies beneath and why we should c are - Dr Sophie Nixon (Manchester) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth Sciences Departmental research seminar with Prof . Paul Wess el (UHM) - Prof. Paul Wessel (UHM) DTSTART;VALUE=DATE-TIME:20220513T120000 DTEND;VALUE=DATE-TIME:20220513T130000 UID:https://talks.ox.ac.uk/talks/id/d70c61dc-ef20-4483-bd9b-d6e2fa0c5542/ DESCRIPTION:\nSpeakers:\nProf. Paul Wessel (UHM) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/d70c61dc-ef20-4483-bd9b-d6e2fa0c5542/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth Sciences Departmental research seminar with Prof . Paul Wessel (UHM) - Prof. Paul Wessel (UHM) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth Sciences research seminar with Dr Ricardo Ramalho - Dr Ricar do Ramalho (Cardiff) DTSTART;VALUE=DATE-TIME:20220506T120000 DTEND;VALUE=DATE-TIME:20220506T130000 UID:https://talks.ox.ac.uk/talks/id/53cdbd24-9011-4fb9-9067-0eee241a30ea/ DESCRIPTION:\nSpeakers:\nDr Ricardo Ramalho (Cardiff) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/53cdbd24-9011-4fb9-9067-0eee241a30ea/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth Sciences research seminar with Dr Ricardo Ramalho - Dr Ricardo Ramalho (Cardiff) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:CANCELLED We are surprised to present evidence for a magmatic sour ce for nitrogen in Earth’s crust - Dr Sami Mikhail (School of Earth & En vironmental Sciences\, St Andrews) DTSTART;VALUE=DATE-TIME:20220204T120000Z DTEND;VALUE=DATE-TIME:20220204T130000Z UID:https://talks.ox.ac.uk/talks/id/bfdffcbc-677c-4435-9747-ae84722c86dd/ DESCRIPTION:The igneous portion of Earth’s continental crust is a major long-term sink of nitrogen on Earth\, but the origin of the nitrogen in th is reservoir remains ambiguous. Possible sources include magmatic differen tiation of mantle-derived melts (i.e. magmatic nitrogen) and/or the burial of biomass (i.e. fixed atmospheric nitrogen). Identifying the primary sou rce of crustal nitrogen is thus important for accurately reconstructing th e evolution of atmospheric pressure\, and therefore the habitability of Ea rth\, over geologic timescales. Here we present new data from Hekla volcan o\, Iceland\, revealing that magmatic differentiation of a mantle-derived melt can yield up to 23 μg/g of nitrogen in evolved silicate rocks. By co mparison with compiled literature data\, we find that this level of enrich ment can satisfy 35-52% of Earth’s granitic crust-hosted nitrogen\, a si gnificant portion of upper crustal lithologies. These results show that ni trogen is not always degassed from magmatic systems\; instead\, the format ion of Earth’s continental crust acts as a trap of nitrogen between the mantle and the atmosphere\, which is important to consider in models of at mospheric formation and evolution over geological timescales.\nSpeakers:\n Dr Sami Mikhail (School of Earth & Environmental Sciences\, St Andrews) LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/bfdffcbc-677c-4435-9747-ae84722c86dd/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:CANCELLED We are surprised to present evidence for a magm atic source for nitrogen in Earth’s crust - Dr Sami Mikhail (School of E arth & Environmental Sciences\, St Andrews) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Earth Sciences Departmental research seminar with Prof Andreas Fic htner - Prof Andreas Fichtner (ETHZürich) DTSTART;VALUE=DATE-TIME:20220304T120000Z DTEND;VALUE=DATE-TIME:20220304T130000Z UID:https://talks.ox.ac.uk/talks/id/2507ab16-72fe-4933-bd3c-3240dac2d27f/ DESCRIPTION:\nSpeakers:\nProf Andreas Fichtner (ETHZürich) LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/2507ab16-72fe-4933-bd3c-3240dac2d27f/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Earth Sciences Departmental research seminar with Prof An dreas Fichtner - Prof Andreas Fichtner (ETHZürich) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Dead shells speak: detecting unsuspected ecosystem change on conti nental shelves - Prof Susan Kidwell (Chicago) DTSTART;VALUE=DATE-TIME:20220225T140000Z DTEND;VALUE=DATE-TIME:20220225T150000Z UID:https://talks.ox.ac.uk/talks/id/96a48ef2-843c-449f-9b35-8a84a9d0fabe/ DESCRIPTION:\nSpeakers:\nProf Susan Kidwell (Chicago) LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/96a48ef2-843c-449f-9b35-8a84a9d0fabe/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Dead shells speak: detecting unsuspected ecosystem change on continental shelves - Prof Susan Kidwell (Chicago) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:The deep biosphere: What lies beneath and why we should care - Dr Sophie Nixon (Manchester) DTSTART;VALUE=DATE-TIME:20220218T120000Z DTEND;VALUE=DATE-TIME:20220218T130000Z UID:https://talks.ox.ac.uk/talks/id/4c891eac-4ded-46f5-bd7a-626a4152356a/ DESCRIPTION:The deep subsurface harbours the unseen majority of microbial diversity on Earth\, and a significant proportion of the planet’s biomas s. Understanding how life operates in these extreme environments highlight s the roles these microbes play in biogeochemical cycles of global signifi cance\, such as the carbon cycle. Such knowledge also helps to define the limits to life on Earth. However\, until recently little was known about t he diversity and function of microbial life in the deep biosphere. With th e recent advent of affordable sequencing technologies and ever sophisticat ed tools to unpick the genetic code\, we now know that the deep subsurface harbours an active and highly diverse biosphere. In this talk I will pre sent data from subsurface environments that highlight the diversity of dee p life\, and its contributions to biogeochemical cycling. Examples will in clude evidence for an active carbon- and sulfur-cycling microbial communit y in a deep borehole in Greenland\, a novel genus of bacteria recovered fr om a 2.5 km deep shale gas well\, and a glimpse of the microbial life deep beneath our feet in the North of England. With these examples I will demo nstrate the power of cutting-edge genomic tools for uncovering the ‘rule s of life’ in the subsurface\, and highlight the significant potential t o put subsurface microorganisms to work for the good of the environment an d society.\nSpeakers:\nDr Sophie Nixon (Manchester) LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/4c891eac-4ded-46f5-bd7a-626a4152356a/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:The deep biosphere: What lies beneath and why we should c are - Dr Sophie Nixon (Manchester) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Deep life\, bio-energetics and biogeochemical cycling in subseaflo or sediments DTSTART;VALUE=DATE-TIME:20220211T120000Z DTEND;VALUE=DATE-TIME:20220211T130000Z UID:https://talks.ox.ac.uk/talks/id/8e36bc94-4cf1-400b-9a78-dfdfe1981056/ DESCRIPTION:Marine sediments are a natural laboratory for understanding ho w environmental factors shape life and geochemical processes over geologic time. A systematic approach to studying this enormous habitat on a large scale has been confounded by the difficulty of accessing marine sediments and the challenges associated with cultivating their microbial inhabitants . Therefore\, the biodiversity and function of the marine subsurface biosp here\, and the biogeochemical processes that subseafloor life mediates\, r emain elusive. Here\, we combine reaction transport and power modelling wi th genomic datasets to better understand and quantify (1) the burial and d egradation of organic carbon in marine sediments\, (2) the energy flux tha t sustains subseafloor life\, and (3) the links between energy and the str ucture and function of deep biosphere microorganisms. Closing the gap betw een biogeochemical and bio-energetic modelling and microbial ecology will ultimately reveal the boundaries of the deep biosphere\, the rate at which it is active\, which reactions are used to gain energy\, and how it impac ts Earth’s biogeochemical cycles.\n\n LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/8e36bc94-4cf1-400b-9a78-dfdfe1981056/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Deep life\, bio-energetics and biogeochemical cycling in subseafloor sediments TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Going platinum: PGE and chalcophile elements from the mantle to mi neral deposits - Dr Hannah Hughes (Exeter) DTSTART;VALUE=DATE-TIME:20220121T120000Z DTEND;VALUE=DATE-TIME:20220121T130000Z UID:https://talks.ox.ac.uk/talks/id/cae344f9-3a1e-4327-93c0-42eb2aecac6e/ DESCRIPTION:Metals such as cobalt and the platinum-group elements (PGE) ar e essential to the development of sustainable technology – from batterie s and fuel cells\, to resist ors in electronics and even in the production of 5G infrastructure. These metals are also classified as critical raw ma terials due to concerns over security of supply\, as they are produced fro m only a handful of deposits in a few countries. Many of these elements\, including platinum (Pt)\, palladium (Pd)\, rhodium (Rh)\, ruthenium (Ru)\, iridium (Ir)\, cobalt (Co)\, nickel (Ni)\, copper (Cu) and gold (Au) have an affinity for sulphur (they are chalcophile) and therefore the most fer tile source of these elements comes from the Earth’s core and mantle. In the mantle\, these important metals are largely hosted at trace concentra tions by base metal sulphides (BMS) and in percentage concentrations in ti ny platinum-group minerals (PGM).\n\n\n\nTo be mineralised and concentrate d into ore deposits\, we must consider how to mobilise these minerals and their precious metal cargo into the Earth’s crust. During partial meltin g of the mantle\, sulphides release a portion of their metal budget into t he magma generated\, but it remains difficult to fully quantify this proce ss given the diversity of sulphide compositions\, let alone understand how PGM become mobilised. And yet\, identifying how metals are mobilised out of the mantle into the crust may have some big implications for the fertil ity of magma\, including exotic low degree partial melts such as carbonati tes\, lamprophyres and kimberlites\, and with it some important consequenc es for mineral exploration. This talk will discuss a range of topics\, fro m the uses and economics of the PGE and other chalcophile critical element s\, to metallogenesis and how these metals end up in ore deposits.\nSpeake rs:\nDr Hannah Hughes (Exeter) LOCATION:online\, via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/cae344f9-3a1e-4327-93c0-42eb2aecac6e/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Going platinum: PGE and chalcophile elements from the man tle to mineral deposits - Dr Hannah Hughes (Exeter) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Paleoclimate in the IPCC\; Climate and ocean circulation in the Ph anerozoic - Dr Dan Lunt (University of Bristol) DTSTART;VALUE=DATE-TIME:20211126T120000Z DTEND;VALUE=DATE-TIME:20211126T130000Z UID:https://talks.ox.ac.uk/talks/id/d8dded68-187a-4fee-8b5a-a0d59d70d0ab/ DESCRIPTION:This talk will be in two parts.\n\nI’ll start off with a sum mary of how paleoclimate data and modelling are incorporated into the most recent IPCC report. This has three main aspects – (a) the contextualis ation of recent and future climate change through changes expressed in the geological record\, (b) the assessment of climate sensitivity (and how th is feeds into future projections and carbon budgets)\, and (c) model evalu ation using paleo proxies. I’ll also briefly touch on how this ultimate ly feeds into the COP negotiations.\n\nSecondly\, I’ll present some rece nt work we’ve been carrying out in Bristol\, including work I’ve been doing over the past two weeks here in Oxford. This is a set of climate mo del simulations covering the entire Phanerozoic. I’ll focus on the ocea n circulation in these simulations\, and how this impacts global mean temp eratures and temperature gradients\, and how these model simulations can b e combined with proxy records to reconstruct global mean temperature throu gh time.\n\nFor an interactive taster of this work\, see www.climatearchiv e.org\nSpeakers:\nDr Dan Lunt (University of Bristol) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/d8dded68-187a-4fee-8b5a-a0d59d70d0ab/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Paleoclimate in the IPCC\; Climate and ocean circulation in the Phanerozoic - Dr Dan Lunt (University of Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Direct and indirect contributions of ocean warming to the last int erglacial sea-level highstand: insights and nuances for future predictions - Dr. Sarah Shackleton (Princeton University) DTSTART;VALUE=DATE-TIME:20211112T133000Z DTEND;VALUE=DATE-TIME:20211112T143000Z UID:https://talks.ox.ac.uk/talks/id/dc2012ee-ac0b-45ea-b8b2-dae0ca95c7f8/ DESCRIPTION:Pinning down the sources contributing to the last interglacial (129 – 116 ka) sea-level highstand may be crucial to understanding the vulnerability of modern ice sheets to global warming. Today\, ocean warmin g plays a direct role in sea level rise through thermal expansion and may play an indirect role in future sea level rise through basal melting and s ubsequent mass loss from the polar ice sheets. \nUsing the novel proxy of noble gas ratios measured in ice cores\, we reconstruct mean ocean tempera ture (MOT) change during the penultimate deglaciation and last interglacia l. We show that peak ocean temperatures were 1.1±0.3°C warmer than today \, contributing 0.7±0.3m to thermosteric sea level. This MOT maximum occu rred at the end of the termination\, coincident with peak Antarctic temper ature. \nWe suggest that most of this enhanced warming was related to a de lay in the resumption of the Atlantic Meridional Overturning Circulation ( AMOC) and a bipolar seesaw response in global temperature change across th e penultimate deglaciation. We also hypothesize that the delayed AMOC reco very and early ocean warming triggered enhanced mass loss from Greenland a nd Antarctica in the early stages of the last interglacial.\n\nSpeakers:\n Dr. Sarah Shackleton (Princeton University) LOCATION:Online via zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/dc2012ee-ac0b-45ea-b8b2-dae0ca95c7f8/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Direct and indirect contributions of ocean warming to the last interglacial sea-level highstand: insights and nuances for future pr edictions - Dr. Sarah Shackleton (Princeton University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Mantle controls over the evolution of oceanic basalts - Dr David N eave (University of Manchester) DTSTART;VALUE=DATE-TIME:20211119T120000Z DTEND;VALUE=DATE-TIME:20211119T130000Z UID:https://talks.ox.ac.uk/talks/id/f968457d-5261-4b0d-a600-e3409e590bc6/ DESCRIPTION:Oceanic basalts are geochemically and isotopically heterogeneo us owing to variations in melting processes and mantle source compositions . Although enriched heterogeneities associated with recycled and primordia l material are well known to contribute to oceanic basalt genesis in many settings\, important roles for highly depleted heterogeneities are also be ing increasingly recognised. However\, variability in oceanic basalts is n ot restricted to their isotopic and trace-element contents\, but also mani fests in their major element contents. This is important because variation s in major element contents result in variable phase equilibria relations that in turn have the potential to affect magma transport and storage proc esses. Here we will use Icelandic basalts as a case study to discuss how m antle-derived geochemical variability imposes fundamental controls on the evolution of oceanic basalts and their crystal cargoes. Firstly\, we will discuss how measuring incompatible elements in olivine reinforces inferenc es made about mantle heterogeneity from melt inclusion archives. We will t hen discuss the results of phase equilibria experiments performed on synth etic analogues of Icelandic lavas that reveal earlier and more extensive c rystallisation in magmas from depleted sources\, which may bias erupted re cords of mantle geochemistry towards magmas from enriched sources. We will then consider how the crystallisation of widespread but cryptic depleted melts at depth may produce the disequilibrium cargoes of anorthitic plagio clase observed in many oceanic lavas\, including in Iceland. Finally\, we will discuss how isothermal mixing between geochemically variable basalts affects plagioclase stability and may trigger mush disaggregation and crys tal entrainment in the run up to Icelandic eruptions.\nSpeakers:\nDr David Neave (University of Manchester) LOCATION:TBC TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/f968457d-5261-4b0d-a600-e3409e590bc6/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Mantle controls over the evolution of oceanic basalts - D r David Neave (University of Manchester) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Segmentation of subducting oceanic plates by brittle-ductile damag e - Prof. Taras Gerya (ETH Zurich) DTSTART;VALUE=DATE-TIME:20211022T120000 DTEND;VALUE=DATE-TIME:20211022T130000 UID:https://talks.ox.ac.uk/talks/id/22fcc8a4-6b20-4bc8-8870-61b762b49827/ DESCRIPTION:Segmentation of subducting oceanic plates by brittle-ductile d amage\n \nT. V. Gerya1\, D. Bercovici2 & T. W. Becker3.4\n1Swiss Federal I nstitute of Technology Zurich\, Department of Earth Sciences\, Zurich\, Sw itzerland.\n2Yale University\, Earth & Planetary Science\, New Haven\, CT\ , United States \n3Institute for Geophysics\, Jackson School of Geoscience s\, The University of Texas at Austin\, Austin\, TX\, United States\n4Depa rtment of Geological Sciences\, Jackson School of Geosciences\, The Univer sity of Texas at Austin\, Austin\, TX\, United States\n\nSubducting oceani c plates experience intense normal faulting during bending that accommodat es the transition from horizontal to downward motion at the outer rise at subduction trenches. We investigated the consequences of the plate bending on the mechanical properties of subducting slabs using 2D subduction mode ls in which both brittle and ductile deformation\, as well as grain size e volution\, are tracked and coupled self-consistently. Numerical results su ggest that pervasive brittle-ductile slab damage and segmentation can occu r at the outer rise region that strongly affects subsequent evolution of s ubducting slabs in the mantle. This slab-damage phenomenon explains the su bduction dichotomy of strong plates and weak slabs\, the development of la rge-offset normal faults near trenches and the occurrence of segmented sei smic velocity anomalies and interfaces imaged within subducted slabs. Furt hermore\, brittle-viscously damaged slabs show a strong tendency for slab breakoff at elevated mantle temperatures that may have destabilised contin ued oceanic subduction and plate tectonics in the Precambrian.\nSpeakers:\ nProf. Taras Gerya (ETH Zurich) LOCATION:Online via Zoom link https://zoom.us/j/95432517745 TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/22fcc8a4-6b20-4bc8-8870-61b762b49827/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Segmentation of subducting oceanic plates by brittle-duct ile damage - Prof. Taras Gerya (ETH Zurich) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Silicic magmatism: granite pluton growth\, magma chamber formation and volcanism - Prof. Steve Sparks (University of Bristol) DTSTART;VALUE=DATE-TIME:20211029T120000 DTEND;VALUE=DATE-TIME:20211029T130000 UID:https://talks.ox.ac.uk/talks/id/b77f4ed3-908f-4ffc-89d2-60ea57d888af/ DESCRIPTION:In this seminar I explore contemporary understanding of silici c magmatic systems with a focus of the formation of large silicic magma ch ambers that are capable of large magnitude explosive eruptions. I discuss silicic melt generation in the middle and lower crust\, melt segregation\, magma transport and mechanisms of forming magma chambers and triggering o f major eruptions.\nSpeakers:\nProf. Steve Sparks (University of Bristol) LOCATION:Department of Earth Sciences (Seminar rooms)\, South Parks Road O X1 3AN TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/b77f4ed3-908f-4ffc-89d2-60ea57d888af/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Silicic magmatism: granite pluton growth\, magma chamber formation and volcanism - Prof. Steve Sparks (University of Bristol) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Biomineralisation and boron proxies: how do shells record archives of seawater carbon chemistry? - Dr Oscar Branson (Cambridge) DTSTART;VALUE=DATE-TIME:20210611T120000 DTEND;VALUE=DATE-TIME:20210611T130000 UID:https://talks.ox.ac.uk/talks/id/43639c42-ee04-4660-a8ce-c8b7f8bb58d1/ DESCRIPTION:Carbonate biominerals play a key role in the ocean carbon cycl e\, and preserve vital archives of past climate change in their geochemist ry. The abundance and isotopic content of boron in carbonate biominerals p rovide our best records of ocean carbon chemistry and pH\, which have prov ed instrumental in studying past episodes of CO2-induced climate change [1 ]. The boron proxies are based on the theory that carbonates solely incorp orate B(OH)4- in proportion to seawater B(OH)4-/HCO3- or B(OH)4-/CO32-\, c apturing both the state of the ocean C system and the pH-dependent isotopi c composition of B(OH)4-. However\, significant modification of internal c arbon chemistry is required to facilitate calcification\, and substantial proton export has been observed during carbonate formation [2]. The pH\, c arbon and boron chemistry at the site of calcification cannot be the same as that of external seawater. How\, then\, do biominerals appear to record seawater B(OH)4-? While unanswered\, this question raises serious problem s for our use and interpretation of the B proxies.I will explore this ques tion using a quantitative model of B transport processes during biomineral isation. Three key fluxes dominate biomineral formation: CaCO3 precipitati on\, the exchange of seawater with the external environment\, and ion tran sport across membranes by diffusion or active pumping [3]. By reducing the problem to the balance between these three key fluxes\, it is possible to explore a wide range of biomineralisation scenarios with minimally restri ctive assumptions. Including both the transport of B(OH)4–\, and the tra nsport and passive diffusion of membrane-permeable B(OH)3 within this fram ework captures the full range of potential biomineralisation scenarios and B transport processes. Sets of B geochemical data from biominerals grown in known conditions then provide crucial constraints that reveal: (1) A me chanism that allows biomineral boron to be sensitive to seawater pH and ca rbon chemistry\, despite significant differences in chemistry and pH at th e site of calcification\, and (2) the ion transport dynamics of the calcif ication environment (e.g. ‘closed’ vs. ‘open’ or Rayleigh- vs. tra nsport-dominated system). Together\, this adds confidence to the use of th e B palaeo-proxies in all carbonate biominerals\, and provides a new lens through which B geochemistry can be used to understand biomineralisation m echanics\, which is particularly relevant to the resilience of coral calci fication to changing ocean carbon chemistry [4].\nSpeakers:\nDr Oscar Bran son (Cambridge) LOCATION:Online\, via zoom link on https://www.earth.ox.ac.uk/events/depar tmental-seminar-week-7/ TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/43639c42-ee04-4660-a8ce-c8b7f8bb58d1/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Biomineralisation and boron proxies: how do shells record archives of seawater carbon chemistry? - Dr Oscar Branson (Cambridge) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Reducing the Earth to Simple Physical Models: From Ice Sheets to E arthquakes - Dr Victor Tsai (Brown University) DTSTART;VALUE=DATE-TIME:20210514T120000 DTEND;VALUE=DATE-TIME:20210514T140000 UID:https://talks.ox.ac.uk/talks/id/d0ab05ad-9065-4353-8ae9-e4d1f362af0e/ DESCRIPTION:The Earth is incredibly complex\, with geophysical processes o ccurring at many different scales that contribute to determining the event ual observed behavior. For example\, the rate at which ice sheets contribu te to sea level rise depends crucially on a heterogeneous\, time varying s ubglacial water network\, and the damaging effects of earthquakes depend c rucially on complex\, intertwining fault zone structure. Due to this compl exity\, many attempts to model Earth systems rely on an empirical\, observ ationally driven approach. However\, such empirical models fail when appli ed to conditions that have not been observed\, making prediction of future behavior and related hazards challenging. Here I discuss how simple physi cal models are useful for modeling complex geophysical processes like ice sheet motion and earthquakes\, particularly with the goal of robust predic tion. On the ice sheet side\, I show that one can account for a heterogene ous\, time varying subglacial hydrologic system in a simplified manner tha t nonetheless produces accurate predictions when applied to the Greenland Ice Sheet. On the earthquake side\, I show that the effects of complex fau lt zone structure on earthquake damage can be evaluated using statistical mechanics and yields predictions of high-frequency ground motions that com pare more favorably with observed ground motions than more complex numeric al simulations.\nSpeakers:\nDr Victor Tsai (Brown University) LOCATION:Online\, via zoom link on https://www.earth.ox.ac.uk/events/depar tmental-seminar-9/ TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/d0ab05ad-9065-4353-8ae9-e4d1f362af0e/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Reducing the Earth to Simple Physical Models: From Ice Sh eets to Earthquakes - Dr Victor Tsai (Brown University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Calibrating changes across the Precambrian-Cambrian transition - D r Emmy Smith (Johns Hopkins University) DTSTART;VALUE=DATE-TIME:20210430T153000 DTEND;VALUE=DATE-TIME:20210430T170000 UID:https://talks.ox.ac.uk/talks/id/394cfa0f-341d-4d07-9c61-cb1493576bb1/ DESCRIPTION:Since Darwin first noted the seemingly abrupt appearance of fo ssils in Cambrian strata\, the cause and tempo of the ‘Cambrian Explosio n’ has remained one of Earth Science’s most provocative research topic s. Contrary to Darwin’s hypothesis that this phenomenon reflected a larg ely eroded and imperfect geological record\, scientists have spent the pas t 70 years unraveling a diverse Precambrian biosphere characterized by the deep roots of eukaryotic evolution. Now\, it is generally agreed upon tha t the Neoproterozoic origins of animals and multicellularity are at least partly related to genetic challenges\; however\, the simultaneous explosio n in body size\, morphological features\, and skeletonization in the Cambr ian is likely the result of external “triggers”\, the nature of which have been widely debated.\nOne of the environmental changes that has been observed in carbonate strata spanning the Ediacaran–Cambrian boundary is high frequency and high magnitude variability in carbon isotopic values ( d13C). Although the causal mechanism(s) behind these d13C excursions are s till debated\, they have been generally assumed to chronicle primary chang es in the net global fluxes of organic carbon burial and oxidation. Thus\, secular changes in these isotopic records have been widely used to develo p three-dimensional frameworks of ancient marine basins\, quantitatively l ink changes in carbon burial to those in atmospheric oxygen\, invoke shift s in the fluxes of isotopically distinct pools of carbon\, and construct a ge models regionally and globally. Using data from multiple Ediacaran–Ca mbrian paleocontinents\, my group members\, collaborators\, and I aim to t est the hypothesis that the d13C excursions across the Ediacaran–Cambria n transition reflect the composition of dissolved inorganic carbon in glob al oceans and are buffered from post-depositional diagenetic effects. Here I will present radioisotopic and stable isotopic geochemical data that ar e grounded in robust geologic frameworks to discuss our current understand ing of how to interpret d13Ccarb records from Ediacaran–Cambrian success ions.\nSpeakers:\nDr Emmy Smith (Johns Hopkins University) LOCATION:Online\, via zoom link on https://www.earth.ox.ac.uk/events/calib rating-changes-across-the-precambrian-cambrian-transition/ TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/394cfa0f-341d-4d07-9c61-cb1493576bb1/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Calibrating changes across the Precambrian-Cambrian trans ition - Dr Emmy Smith (Johns Hopkins University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:A Matter of Time: The Coupled Role of Host Star Age\, Radiogenic H eat Budgets and the Lifetime of Habitable Climates on Rocky Exoplanets - D r Cayman Unterborn (Arizona State University) DTSTART;VALUE=DATE-TIME:20210312T150000Z DTEND;VALUE=DATE-TIME:20210312T160000Z UID:https://talks.ox.ac.uk/talks/id/efd37336-6589-4670-88b1-f3d1ce8998d0/ DESCRIPTION:\nSpeakers:\nDr Cayman Unterborn (Arizona State University) LOCATION:Online\, via zoom link on https://www.earth.ox.ac.uk/events/dr-ca yman-unterborn/ TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/efd37336-6589-4670-88b1-f3d1ce8998d0/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:A Matter of Time: The Coupled Role of Host Star Age\, Rad iogenic Heat Budgets and the Lifetime of Habitable Climates on Rocky Exopl anets - Dr Cayman Unterborn (Arizona State University) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Pseudofossils and the search for life on Mars - Dr Sean McMahon (E dinburgh) DTSTART;VALUE=DATE-TIME:20210122T120000Z DTEND;VALUE=DATE-TIME:20210122T130000Z UID:https://talks.ox.ac.uk/talks/id/2998c664-294c-4601-a7e7-3d4e7a62f519/ DESCRIPTION:Two forthcoming rover missions (NASA’s Perseverance rover an d the ESA/Roscosmos Rosalind Franklin rover) aim to seek geological biosig natures (fossils\, broadly conceived) in rocks formed in habitable environ ments on early Mars. Promising samples found by Perseverance may later be returned to Earth for further analysis. An important aspect of the search for biosignatures on Mars is the need to exclude “false positive” resu lts. As palaeobiologists know very well\, microbial fossils can be difficu lt to distinguish from misleadingly lifelike geochemical and morphological signals produced by abiotic processes. Here\, I will: (1) suggest several ways in which pseudofossils might have formed on early Mars\; (2) reinter pret some high-profile purported fossil microbes (including Earth’s supp osed oldest) as probable pseudofossils in light of experimental results\; (3) present a new assemblage of dubiofossils from a Mars-analogue palaeoen vironment\; (4) critically discuss the ways in which palaeobiologists and astrobiologists (including Oxford’s late Martin Brasier) have dealt with the problem of pseudofossils in the past. I will conclude that astrobiolo gists need to work with physical chemists to explore the range of lifelike objects\, patterns and substances that far-from-equilibrium geochemical p rocesses can produce.\nSpeakers:\nDr Sean McMahon (Edinburgh) LOCATION:Join via Zoom link TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/2998c664-294c-4601-a7e7-3d4e7a62f519/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Pseudofossils and the search for life on Mars - Dr Sean M cMahon (Edinburgh) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Volatile recycling at the Lesser Antilles subduction zone - Profes sor Jenny Collier (Imperial College) DTSTART;VALUE=DATE-TIME:20201120T120000Z DTEND;VALUE=DATE-TIME:20201120T130000Z UID:https://talks.ox.ac.uk/talks/id/289a7725-17e0-4f3b-b300-25356149d5dd/ DESCRIPTION:The subduction water cycle is a key process for understanding the long-term evolution of surface water\, arc volcanism\, mantle hydratio n and convection. Seismic hazard may also be directly influenced by spatia l variations in the hydration of the incoming plate. Much of our current u nderstanding of these processes comes from studies in the Pacific where fa st-spread oceanic lithosphere is subducted. In this talk I will present re sults from project VoiLA (2015-2021) – a NERC-funded large grant that ta rgeted the Lesser Antilles subduction system in the slow-spread Atlantic. Using active-source seismology I will show that the Atlantic lithosphere i s much wetter and more laterally variable than Pacific lithosphere. These results\, when mapped onto the slab\, show a clear correlation with mantle wedge properties obtained from passive-source seismology and arc geochemi stry. Our ability to track volatiles through the system offers the potenti al to improve global budget estimates and local hazard assessment.\n\nSpea kers:\nProfessor Jenny Collier (Imperial College) LOCATION:Venue to be announced TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/289a7725-17e0-4f3b-b300-25356149d5dd/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Volatile recycling at the Lesser Antilles subduction zone - Professor Jenny Collier (Imperial College) TRIGGER:-PT1H END:VALARM END:VEVENT BEGIN:VEVENT SUMMARY:Does the Antarctic Ice Sheet care about Earth Rheology? - Dr. Pipp a Whitehouse (Durham University) DTSTART;VALUE=DATE-TIME:20201204T120000Z DTEND;VALUE=DATE-TIME:20201204T130000Z UID:https://talks.ox.ac.uk/talks/id/d43dffcc-7f1b-4b38-a468-7afa6c23066a/ DESCRIPTION:The 2007 IPCC 4th Assessment Report did not account for dynami cal ice sheet change within its projections of future sea level due to lim ited understanding of the processes involved and a lack of consensus on th eir magnitude. Since then\, our understanding of ice sheet dynamics has ex panded dramatically thanks to significant advances in our ability to measu re and model the drivers of ice sheet change. The majority of research has focused on climatic factors controlling ice sheet change but in this talk I will consider an important non-climatic factor: the role of the ice she et bed. \n\nBasal conditions determine whether an ice sheet slides freely or is frozen to its bed\, but for a marine-grounded ice sheet such as Anta rctica\, the shape of the bed also plays an important role as it determine s whether the ice sheet can recover from short-term ice loss or whether it is likely to tip into a state of unstable retreat. Crucially\, the curren t shape of the bed beneath West Antarctica means that it is at risk of run away ice loss. I will describe various factors that may play a role in des tabilizing or stabilizing this ice sheet\, including a negative feedback p rocess\, related to the isostatic response of the solid Earth to ice sheet change\, that has the potential to slow the rate of ice loss. The strengt h of this feedback depends on the rheology of the upper mantle and I will describe recent efforts to determine the material properties of the solid Earth beneath Antarctica\, drawing on both modelling and observational app roaches. \nSpeakers:\nDr. Pippa Whitehouse (Durham University) LOCATION:Join via Zoom webinar TZID:Europe/London URL:https://talks.ox.ac.uk/talks/id/d43dffcc-7f1b-4b38-a468-7afa6c23066a/ BEGIN:VALARM ACTION:display DESCRIPTION:Talk:Does the Antarctic Ice Sheet care about Earth Rheology? - Dr. Pippa Whitehouse (Durham University) TRIGGER:-PT1H END:VALARM END:VEVENT END:VCALENDAR