The Shuram anomaly: What caused the largest ever carbon isotope anomaly and what can it tell us?
The late Ediacaran Shuram anomaly is the largest carbon isotope 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 sustained perturbation to the global carbon cycle. The Shuram anomaly is now known to be sandwiched between two major glaciations but is itself associated with global warming and biological radiations of benthic animals across an increasingly oxidised seafloor. Low organic burial rates during the Shuram anomaly are consistent with independent evidence for highly efficient organic remineralisation, implying net transfer of oxidising power from rock sulphate to the carbon cycle. Other negative anomalies occurred between 1.6 and 0.5 Ga, and preceded all Neoproterozoic glaciations. This talk will consider whether ‘sink-switching’ between the sulphur and carbon rock reservoirs was a defining characteristic of the Proterozoic Earth system.
Date: 29 November 2024, 12:00 (Friday, 7th week, Michaelmas 2024)
Venue: Department of Earth Sciences, South Parks Road OX1 3AN
Venue Details: Seminar Rooms
Speaker: Prof Graham Shields (UCL)
Organising department: Department of Earth Sciences
Part of: Earth Sciences departmental seminars
Booking required?: Not required
Booking url: https://www.earth.ox.ac.uk/event/the-shuram-anomaly-what-caused-the-largest-ever-carbon-isotope-anomaly-and-what-can-it-tell-us
Audience: Public
Editor: Maria Petrunova