江苏岸外海底沙脊群的物质来源

本文通过对江苏岸外海底沙脊群的沉积物的粒度、矿物和孢粉以及沉积结构、构造的分析研究,并与苏北废黄河水下三角洲、古长江水下三角洲、现代长江水下三角洲以及长江三角洲平原第四纪地层的沉积物的对比分析,指出江苏岸外海底沙脊群的沉积物主要是晚更新世冰期古长江入海的物质。

THE SEDIMENT SOURCES OF THE OFFSHORE SUBMARINE SAND RIDGE FIELD OF THE COAST OF JIANGSU PROVINCE

This study has verified that the sediment of the offshore submarine ridges field of the north Jiangsu mainly came from the old Changjiang River during the late Pleistocene. The sediment samples took from submarine ridges have boon analysised for size, heavy mineral, clay mineral, spore and pollen etc. and also compared those date with those of the sediments of the subaqueous deltas of the old Yellow River, the old and modern Changjiang River. It can be pointed out that the components of the sediment of submarine sand ridges are as same as those of the old Changjiang River, but quite different from those of old Yellow River in size, mineral, pollen and spore. The studies of the characteristics of lithologic, sediment structures and depositional environmont of a series of cores from the coast area faced offshore sand ridges field have indicated that the coast zone was ancient Changjiang estuary during the late Pleistocene lower sea level. The Changjiang River emptied its sediment into Yellow Sea and built up a larger river delta. While the Changjiang moved down to the south, the old delta has been reformed to be a submarine sand ridge group during Holocene transgression, and the ancient estuary had boon filled up to be a series of large lakes and gradually formed today's coast plain.