The authors selected two cores in the Yangtze estuary, one within the region of seasonal hypoxia (named CJ43 core) and the other nearby but outside the hypoxia region (named CJ56 core). The grain size and elements, including ten kinds of major elements and thirteen kinds of trace elements, were determined on the 210Pb-dated sediment cores. The two core sediments had different resources and represented different element distribution characteristics. Major sources of the CJ56 core sediment were from the old