莺歌海附近陆架区埋藏古河道及海平面变化

用高分辨率地球物理仪,在莺歌海陆架区海底发现了大量埋藏古河道、古湖泊。根据其分布位置及断面特征,推测出更新世末期低海面时期埋藏古水系的分布。据沉积物层中的超覆层序及埋藏古河道的端点水深推测,晚更新世末期调查区最低海平面的位置在130—140m等深线附近。     

南黄海埋藏古河系研究

1987—1989年浅地层测量结果表明,南黄海海底存在许多埋藏古河道、古湖泊、古三角洲,它们组成一个完整的水系。据矿物分析和化学成分分析,北部的古河道为古黄河水系,南部的为古长江水系,二者有可能一度汇合于南黄海中部。它们可能形成于2.5—0.9万年以前的低海面时期。成山角东部的下部地层中发现更老的古河道,可能为中更新世古黄河河床。在南黄海中部80m水深处发现了低海面时期的古黄河、古长江三角洲,那里约为2.5万年以前的古海岸线。     

BURIED PALEO-CHANNEL SYSTEM AND RECORDS OF SEA LEVEL CHANGE ON THE CONTINENTAL SHELF IN YINGGE SEA BASIN

High resolution geophysical instruments were used to locate many buried paleo-channels. paleo-lakes, and river mouth paleo-deltas formed during low sea level at the end of Late Pleistocene and Early Holocene. Some paleo-rivers flowed southward into the paleo-lake and others southeastward into the Paleo-South China Sea. It may be inferred from data on buried paleo-channels that sea level remained for some time at the -50m (longest time here). -100m, and -130 to -140 m(lowest level) water depths, and that corresponding paleo-coastlines were formed at the respective depths.