南海主要控凹断层活动特征与新生代地壳初始张裂  

Activity characteristics of main sag-controlling faults and Cenozoic initial crustal rifting in the South China Sea

作　　者：鞠东 邱燕[1,2] 黄文凯 杜文波 JU Dong;QIU Yan;HUANG Wenkai;DU Wenbo(Guangzhou Marine Geological Survey,China Geological Survey,Guangzhou 510075,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 510075,China)

机构地区：[1]中国地质调查局广州海洋地质调查局,广州510075 [2]南方海洋科学与工程广东省实验室(广州),广州510075

出　　处：《海洋地质前沿》2022年第9期59-70,共12页Marine Geology Frontiers

基　　金：国家联合基金项目(U20A20100);中国地质调查局项目(DD20221712)。

摘　　要：基于贯穿南海南、北陆缘2条长地震剖面的资料解释,分析了南海海域主要控凹断层的活动特征及其新生代地壳初始张裂特征。南海陆缘大部分断层于新生代张裂期开始发育并强烈活动,控凹断层基本上都发育在凹陷的边界,又称之为控凹边界断层。多数控凹断层早期以断块旋转滑脱、形成铲状断层为特征,北部陆缘主要控凹断层多数还具有幕式断裂的活动特点。控凹断层的初始活动时间主要集中在早始新世-晚渐新世,在南海北部陆缘东部早于西部,东部断层初始活动时间为早始新世甚至更早,西部断层初始活动时间多为晚始新世;南海南部陆缘的控凹断层初始活动时间晚于南海北部陆缘,主要集中在中始新世甚至晚始新世。南海海域地壳新生代初始张裂活动时间具有“东早西晚、北早南晚”的特点。此外,这些控凹断层部分于南海的漂移期继续活动或开始活动,少数断层于中中新世重新活动。Based on the data interpretation on two long seismic transections across the southern and northern continental margins of the South China Sea,we analyzed the activity characteristics of the main sag-controlling faults in the South China Sea and the initial tensile fracture characteristics of the Cenozoic crust.Most of the faults began to develop and move strongly during the Cenozoic period of tensile fracture.The sag-controlling faults are usually developed at the sag boundary,also known as the sag-controlling boundary faults.In the early stage,the most sag-controlling faults are characteristic of rotation and detachment of fault blocks and the formation of listric faults.Most of the main sag-controlling faults in the northern continental margin are episodic faults in characteristics,and the initial activity time is mainly from the Early Eocene to Late Oligocene.In particular,the initial activity time of faults in the eastern part is the Early Eocene or earlier,and that in the western part is the Middle Eocene or later.In the southern continental margin of the South China Sea,the initial activity time of sag-controlling faults is later than that in the northern continental margin,mainly concentrated in the Eocene or Late Eocene.It can be seen that the initial activity time of the Cenozoic crustal tension in the South China Sea presents the characteristics of"early in the east and late in the west,and early in the north and late in the south".In addition,some of the sag-controlling faults continued or began to move during the drifting period of the South China Sea,and a few faults reactivated in the Miocene.

关 键 词：控凹断层 断层活动特征 陆缘区 新生代地壳初始张裂 南海 

分 类 号：P736[天文地球—海洋地质]