摘要
以三维地震剖面的解释为基础 ,在东营凹陷古近纪裂陷期充填序列中识别出了一条在全盆地范围内可以追索对比的区域性不整合界面S6′,该界面构成了盆地沙三段的底界 .盆地充填地层的厚度和构造应力场分析揭示 ,S6′界面将盆地古近纪同裂陷期的演化划分为 2个不同构造应力场控制的裂陷幕 ,即裂陷Ⅰ -Ⅱ幕和裂陷Ⅲ -Ⅳ幕 .前者受控于近南北向的拉伸应力场 ,形成了分别由NWW向的陈南断裂和石村断裂带控制的半地堑式断陷盆地 ;后者受控于NW -SE向的拉伸应力场 ,形成了由NE向的断裂系统控制的半地堑式断陷盆地 .S6′界面的发育是区域性的 ,在渤海湾盆地和中国东部的许多盆地中均可追索 ,其发育的时代为中始新世晚期 (43.5Ma) ,并且与印度洋板块和太平洋板块新生代期间的一次重大的运动学调整的时间一致 ,因此 ,S6′界面的识别有可能为中国东部新生代盆地形成演化的动力学背景的研究提供新的信息 .
A regional unconformity-S_(6′) is distinguished in Tertiary filling sequence of Dongying depression by interpretation of 3D seismic profiles. This sequence boundary lies on the bottom of the 3rd Member, Shahejie Formation and can be traced and contrasted in the whole basin area. Analysis on stratigraphic thickness and tectonic stress field of the basin reveals that S_(6′) boundary divided the Tertiary synrifting stage into two episodes controlled by different tectonic stress fields, that is, the first episode of basin development and the second episode of basin development. The former was controlled by N-S trending extensional tectonic stress field, forming half grabens bounded by Chennan fault and Shicun fault; while the latter was controlled by NW-SE trending extensional tectonic stress field, forming half graben bounded by NE trending fault system. S_(6′) boundary is a regional unconformity and can be found and traced in Bohai gulf basin and many other basins in East China. The boundary occurred in late Middle Eocene, which was consistent with the time of a great reorganization of global plate tectonics during Cenozoic. Thus identification of S_(6′) boundary may provide new information for dynamic setting of formation and evolution of Cenozoic basins in East China.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2004年第1期69-76,92,共9页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金项目 (No .40 3 72 0 67)
