Roles of sediment supply, geochemical composition and monsoon on organic matter burial along the longitudinal mud belt in the East China Sea in modern times

Terrestrial sediment supply and its composition, aquatic productivity and coastal hydrodynamics together control the nature of organic matter (OM) that buried in ocean margins. Distinguishing their individual roles in river-dominated continental margins is challenging, but crucial for understanding (i) the regional carbon cycle in modern times and (ii) the OM burial-climate link on shorter timescales. Here we investigate the contents of total organic carbon (TOC) and total nitrogen (TN) and stable carbon isotopic composition of TOC (δ13C), along with grain size and calcium carbonate, in three short, 210Pb- and 137Cs-dated, sediment cores (DH1-1, DH3-3 and DH5-1) from the Yangtze distal mud belt in the East China Sea to delineate the spatiotemporal distribution, origin and burial flux of sedimentary OM for the last ca. 130 years. We also use selected inorganic elements (Si, Al, Ca, Na, K, Rb and Sr) and geochemical proxies derived from them (i.e. chemical index of alteration-CIA, molar Al/Si, molar K/Na, K/Rb and Rb/Sr) to elucidate the importance of detrital composition and chemical weathering on the supply, transport and burial of OM.