Distribution and source of sedimentary organic matter in the eastern Yellow Sea

Abstract

The Yellow Sea is a semi-enclosed marginal sea between China and the Korean Peninsula in the northwest Pacific region, receiving large amounts of terrigenous sediments from one of the largest rivers in the world, the Changjiang River (Yangtze River), as well as smaller Korean rivers such as the Han River, the Geum River, and the Yeongsan River. In this study, we collected 117 surface sediments using a Van Veen grab sampler in the eastern part of the Yellow Sea. We investigated the distribution and source of sedimentary organic matter, by applying a modified method of the Rock-Eval pyrolysis. The hydrogen indices vary between 77 and 1500 HC/gTOC. Hence, our results suggest that most of sedimentary organic matter are a mixture of Type II kerogen with algal and bacterial origin and Type III kerogen with higher plant organic matter. The Tmax values are less than 435℃, indicating most of sedimentary organic matter are thermally immature.