Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361)

Abstract. Extensive black shale deposits formed in the Early Cretaceous South Atlantic, supporting notion that this emerging ocean basin was a globally important site of organic carbon burial. The magnitude burial marine basins is known to be controlled by various tectonic, oceanographic, hydrological, and climatic processes acting on different temporal spatial scales, nature relative importance which are poorly understood for young Atlantic. Here we present new bulk molecular geochemical data from an Aptian–Albian sediment record recovered deep Cape Basin at Deep Sea Drilling Project (DSDP) Site 361, combine with general circulation model results identify driving mechanisms A multimillion-year decrease (i.e., Aptian–Albian) burial, reflected lithological succession shale, gray red beds, caused increasing bottom water oxygenation due abating hydrographic restriction via Atlantic–Southern Ocean gateways. These emphasize evolution gateway development as decisive primary control enhanced preservation geological timescales (> 1 Myr). Aptian sequence comprises alternations shales high 6 %) relatively low (∼ 3.5 content sources, former being deposited during global Oceanic Anoxic Event (OAE) 1a, well repetitive intervals before after OAE 1a. In all cases, these short-term coincided strong influxes sediments derived proximal African continent, indicating closely coupled climate–land–ocean interactions. Supported our results, show fluctuations weathering-derived nutrient input southern linked changes orbitally driven humidity aridity, were underlying drivers episodes Basin. suggest environments responded sensitively directly riverine fluxes. We explain relationship using lack wide mature continental shelf seas could have acted barrier or filter transfer continent into ocean.