Marine silicate alteration plays a key role in the global carbon and cation cycles. This study investigates surface sediments across the Peruvian margin before and after extreme rainfall and runoff (coastal El Niño) using Ge/Si ratios and laser-ablated solid and pore fluid Si isotopes (δ³⁰Si). Pore fluids following the rainfall show elevated Ge/Si ratios and δ³⁰Si values, related to rapid authigenic clay formation from reactive terrigenous minerals delivered by continental runoff. The study highlights the direct coupling of terrestrial erosion and marine sedimentary processes, showing that marine silicate alteration can be rapid and highly dynamic, impacting marine alkalinity and CO₂-cycling on short timescales.

Sonja Geilert, Daniel A. Frick, Dieter Garbe-Schönberg, Florian Scholz, Stefan Sommer, Patricia Grasse, Christoph Vogt, Andrew W. Dale