南黄海盆地南部拗陷前第三纪基底性质分析及含油气远景

Analysis of Pretertiary Basement & Its Exploration Prospects In South Depression of SYS Basin

重磁力场特点表明,南黄海盆地南部拗陷和勿南沙隆起具有相似的特点,推测在重力界面和磁性基底间有着4-5公里厚的沉积层,属下扬子地台东延区.这套地层为古生界到三叠系,组成了南部拗陷前第三系的基底,并已被钻井所证实。根据下扬子地区印支运动左旋应力场的分析,本区前第三系基岩的走向应是北东向,因受北西向南东的较弱挤压力影响,产生了一系列北西、北西西向断层,使构造复杂化。

Gravity and magnetic data of South depression of South Yellow Sea (SYS) basin indicate that the depression is similar to Funaansha massif in characters and there are 4-5km sediments, belonging to the east extension of the lower Yangtse, Platform between the gravity surface and the magnetic basement. The sediments are believed of Paleozoic to Triassis ages and are economic Pretertiary basement of South depression, supported by drilling data. The basement should strike NE as the Platform was under left-lateral stress during the Indo-China movement. However, a number of faults extending NW or NWW devloped in response to relatively weak compressional stress from NW to SE, which complicated the striking and tectonic features of the basement.