Sandy Turbidity Current Acts as a Rusty Carbon Pump at the Shelf Edge

Abstract Sandy turbidity currents (STCs) efficiently sequester organic carbon (OC) through rapid burial. Yet our understanding of OC preservation within STC deposits remains far less constrained, especially considering STC deposits as an inferred major sink for iron‐bound OC (Fe‐OC), a long‐term stabilized form of OC. Here, we investigate a sediment core with five STC events from the northern slope of the South China Sea (SCS) and compare our observations against a globally compiled sedimentary Fe‐OC data set synthesized from published literature. We demonstrate that STC deposits host a higher Fe‐OC contribution (22.1% ± 7.6%) than background deposits. STCs drive rapid Fe‐OC transportation from shelf to slope under elevated accumulation rates (185.4 ± 84.6 g m −2 time −1 ). This process shields Fe‐OC from remineralization and favors the formation of refractory OC stabilized within iron matrices. We propose that STCs constitute a “rusty carbon pump,” and that continental slopes represent potential hotspots for long‐term Fe‐OC preservation.