In this talk I’ll synthesize recent research interrogating how variations in weathering regimes and sediment deposition have impacted the chemistry of igneous rocks. In particular, I will focus on a particular class of granites (often termed “S-type”) which form via partial melting of siliciclastic sedimentary rocks and are uniquely suited to capture how the chemical consequences of sedimentary incorporation into magmas have varied throughout Earth history. I will focus on how enhanced organic matter and clay deposition at various periods in Earth history are reflected 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.