摘要
本文在对水深较大的滨外沙脊区钻孔、柱状样岩心详细观察的基础上,综合分析已有资料,并对该区浅地震地层剖面和水下沙脊的卫片进行了解译,提出南黄海陆架沙脊最早的形成年代为距今4000年,而现代的潮流沙脊形成于距今2000年以来的最近时期,潮流沙脊是在海面稳定、强潮流发育和大量物质供给的条件下形成和发展的,潮流沙脊的沉积物主要来自黄河和淮河;现代滨外沙脊具有向西北方向迁移、纵向延伸长度不断萎缩的动态演化特征。
From comprehensive analysis of former informations, detailed study of cores and interpretations of shallow-seismic sections and satellite photographs of sand ridges in the South Huanghai Sea shelf, the following conclusions are drawn:
1. Since late Pleistocene, the offshore sand-ridge area has, in turn, undergone the following environment evolution stages: lake, salt marsh, lagoon, tidal shallow, salt marsh, tidal shallow, littoral region and shallow sea.
2. Sand ridges in the Huanghai Sea shelf were initially formed at 4000a B. P.. And modern tidal sand ridges were newly formed bodies(2000a B. P.) after sea-level fell and the former tidal sand ridges were buried.
3. Stable sea level, strong tidal current and the supply of large quantities of sediments are essential conditions to form tidal sand ridges. First scattered shoals, shallows and tidal channls came as a result of strong tidal action on sea-bottom sediments during 6000-5000a B. P., then sand ridges, perpendicular to the coastline, formed at 4000a B. P.. The deep water parts were buried at 2500a B. P.. Since 2000a B. P., the pattern of gulf has been formed gradually, and the sand ridges have become large-scale, radiating tidal sand ridges because of radial-collecting and radial-diffu. sing tidal currents. Storm tide is also an agent to form the tidal sand ridges.
4. The tidal sand ridges are not reworked mouth bars of the ancient Changjiang River, but resedimented clasts of the Huanghe and Huaihe River sediments reworked by strong tidal currents.
5. The modern offshore sand ridges gradually migrate northwestwards with their longitudinal length reduced.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
1991年第2期25-35,共11页
Marine Geology & Quaternary Geology
基金
地质行业基金资助项目
关键词
陆架
沙脊
成因
演变
黄海
tidal ridge origin material source development the south Huanghai Sea
