摘要
利用精细地貌图、高分辨率多道地震剖面等资料研究南海北部大陆边缘深水陆坡的地貌形态及控制因素。莺琼陆坡具有不同于其他部分的特殊性,红河物源是造成它的地貌形态的主控因素,南海北部陆坡的其他部分的地貌形态依然受控于古新世—渐新世的断陷期所形成的凹凸格局,其空间分布状况决定了陆坡地貌的形态和演变;物源类型和供给数量是陆坡地貌形态的次级因素,决定着陆坡地貌在总体框架下的局部特征,地震和海流等外动力因素则在一定程度上决定了陆坡沉积类型和微地貌形态。南海北部的这种特点与大西洋两岸的大部地区有显著区别,后者在晚侏罗—早第三纪的断陷期所形成的构造格局对陆坡地貌的影响已次于物源状况和向深水的物质分散体系。南海北部陆坡可自西而东依次划分为五段:莺琼陆坡段、神狐陆坡段、珠江海谷段陆坡、东沙陆坡段和台湾浅滩陆坡段;各陆坡段的地貌形态和走向上的差异全面反映了以上三个因素,尤其反映了断陷期构造格局分布状况的效应。
On the basis of the study of the fine geomorphology and high-resolution multichannel seismic profile, A conclusion that the tectonic framework of rift from Paleocene to Oligocene is the natural controlling factor to the geomorphology of slope of the northern South China Sea is drawn. The distribution of rifts and corresponding highs controls their geomorphology and evolution. Besides this type and amount of matter source modify the geomorphology of slope and influence the local characteristics under the general framework. External forces, such as seismic activities and deep-water current, may control the kind of sedimentation and its microgeomorphology to some extent. These characteristics are different from both sides of the Atlantic whose rifting is from Late Jurassic to Palaeogene, so the tectonic framework of both sides of the Atlantic has less influence than source of sediment and its dispersal system. On the basis of such study the slope of the northern South China Sea can be divided into five segments from west to east： Ying--Qiong slope segment, Shenhu slope segment, Zhujiang Valley slope segment, Dongsha slope segment and Taiwan Bank slope segment.
出处
《海洋学报》
CAS
CSCD
北大核心
2008年第2期70-79,共10页
基金
国家自然科学基金资助项目(40572067)
关键词
南海
陆坡
断陷期
地貌
物源
外动力
South China Sea
slope
rift epoch
geomorphology
matter source
external forces
