Geochemistry of surface sediments off the southern and western coasts of Korea

The continental shelf off the southern and western side of the Korean Penin sula is part of a modern epicontinental sea, and is an effective sediment t rap for elastic material derived from China and Korea. We have analyzed 179 surface sediment samples from this shelf for Al, Fe, Na, K, Mg, Ca, Ti, P, Mn, Sr, Ba, V, Cr, Co, Ni, Cu, Zn, organic carbon and calcium carbonate in order to determine the geochemical characteristics of these sediments. Res ults showed a wide range of element contents which are mainly related to th e textural variability of sediments. Exceptions to this were found in the c ontents of Ca, K, Sr and Ba. The Ca and Sr contents were largely determined by the amounts of carbonate present. The K content, on the other hand, app eared to be influenced by both the contents of illite and feldspar, and Ba, of potassium feldspar. For muds (i.e., sediments deposited under present-d ay conditions), it is possible to distinguish those in the central Yellow S ea from those in the Keum Estuary: the former are characterized by high con tents of Fe, Na, K, Mg, Ca and V, and the latter by high contents of Mn, Ba and Co. These differences become more apparent when these elements are nor malized relative to Al in order to minimize grain size effects. The distrib ution of V/Al ratios is different from that of other elements: the highest V/Al values occur in muds from the central Yellow Sea derived from the Huan ghe (the Yellow River in China), whereas the highest values of Mn/Al are fo und in the nearshore area adjacent to the Korean Peninsula. Based on these results, it is suggested that the sources of fine sediments in the Yellow a nd South Seas can be distinguished from the geochemical characteristics of the surface sediments. In the Yellow Sea, two different sources of fine-gra ined sediments can be seen, the Huanghe and the Keum River. The former is c haracterized by higher V contents and the latter by higher Mn contents. Usi ng the V/Al ratio as an end-member component of the two source materials, t he dispersal patterns of the fine sediments (> 6empty set) were also derive d. (C) 1999 Elsevier Science B.V. All rights reserved.