渤海海域新近纪断层成因与动力学状态  

The genesis of the faults and the geodynamic environment during Neogene for offshore of the Bohai sea

作　　者：詹润[1] 朱光[1] 杨贵丽[2,3] 林少泽[1] 严乐佳[1] 姜芹芹[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009 [2]中石化胜利油田分公司地质科学研究院,山东东营257015 [3]成都理工大学沉积地质研究院,四川成都610059

出　　处：《地学前缘》2013年第4期151-165,共15页Earth Science Frontiers

基　　金：中国地质调查局工作项目(1212011120104);国家自然科学基金重大研究项目(91214301);中石化集团公司项目(P10013)

摘　　要：新近纪是渤海海域新构造运动的重要阶段,具有不同于第四纪以来的构造活动特征和盆地格局。大量的盆地勘探资料显示,海域新近系内发育了大量张性、张扭性断层,主要为近东西向断层,其次为北北东向的郯庐断裂带和局部的大型北西向断层。这一断层格局与下伏古近系相似,但断层活动强度明显较弱,属于坳陷型盆地内的断层活动。断层的平、剖面特征表明,近东西向者为正断层,北北东与北西向断层分别为右行、左行平移正断层。各类断层的运动学特征指示,海域古近纪处于南北向的弱伸展环境。近东西向断层小型者多为新生正断层,大型者常是早期断层的复活,皆为区域拉张作用的直接结果。北北东向的郯庐断裂带与北西向断层皆为继承性活动,其走滑是斜向拉张的结果。郯庐断裂带较强的张扭性活动一方面使旁侧派生了一系列北东—北东东向的小型正断层,另一方面使其旁侧各类断层密度明显增大。海域新近纪的弱伸展环境结束于新近纪末一次区域性挤压事件。The Neogene is an important phase of the neotectonic movement in the Bohai sea,and the activity characteristics and basin framework during this period are different from that in the Quaternary.A number of basin exploratory data show that many E-W striking,tensional or transtensional faults appear in Neogene strata.They include predominant E-W striking faults,the NNE-striking Tan-Lu fault zone and some local large NW-striking faults.Fault framework of the Neogene is similar to that in the underlying Palaeogene state.They show weaker activity intensity and development in depressive basins.Cross-section and planar features of the faults demonstrate that the E-W striking faults are normal ones,the NNE-striking faults are sinistal normal ones and the NW-striking faults are dextral normal ones.Kinematics of the faults reveals that the Bohai Sea was in a weaker,N-S extension setting during the Neogene.The E-W striking normal faults are all produced directly by regional extension.Most of the smaller ones were newly developed whereas most of the larger ones formed through reactivation of pre-existing faults.The NNE-striking Tan-Lu fault zone and NW-striking faults all show inherited activities as a result of oblique extension.The more intensive transtensional faulting along the Tan-Lu fault zone induced a series of NE-NEE striking small normal faults and caused increasing density of all kinds of faults around it.The Neogene weak extension environment of the Bohai Sea was terminated in a regional compressional event at the end of the Neogene.

关 键 词：渤海海域 新近纪 断层成因 动力学状态 郯庐断裂带 张扭性走滑 反转事件 

分 类 号：P542.3[天文地球—构造地质学]