Extensional structures of the Nan'an Basin in the rifting tip of the South China Sea: Implication for tectonic evolution of the southwestern continental margin  

作　　者：Shi-Guo Wu Li Zhang Zhen-Yu Lei Xing Qian Shuai-Bing Luo Xiang-Yang Lu Thomas Lüdmann Lei Tian 

机构地区：[1]Laboratory of Geophysics and Georeouce,Institute of Deep-sea Science and Engineering,China Academy of Science,Sanya,Hainan 572000,China [2]MLR Key Laboratory of Marine Mineral Resources,Guangzhou Marine Geological Survey,Guangzhou,Guangdong 510075,China [3]South Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai,Guangdong 519000,China [4]University of China Academy of Sciences,Beijing 100049,China [5]Institute for Geology,CEN,University of Hamburg,Hamburg,20146,Germany [6]Research Institute of Petroleum Exploration and Development Northwest Branch,Lanzhou,Gansu 730000,China

出　　处：《Petroleum Science》2023年第1期128-140,共13页石油科学（英文版）

基　　金：This research was financially supported by Natural Science Foundation of China(U1701245,No.91228208);CGS project(DD20190213);CNPC project(kt 2021-02-02).

摘　　要：Nan'an Basin is a giant hydrocarbon basin,but its tectonic division scheme and associated fault systems has not been well understood.Based on newly acquired seismic data from the southwestern margin of the South China Sea,this study analyzed the structural units,tectonic feature and geodynamics of the sedimentary basin.The new data suggests that the Nan0 an Basin is a rift basin oriented in the NE-SW direction,rather than a pull-apart basin induced by strike-slip faults along the western margin.The basin is a continuation of the rifts in the southwest South China Sea since the late Cretaceous.It continued rifting until the middle Miocene,even though oceanic crust occurred in the Southwest Subbasin.However,it had no transfer surface at the end of spreading,where it was characterized by a late middle Miocene unconformity(reflector T3).The Nan'an Basin can be divided into eight structural units by a series of NE-striking faults.This study provides evidences to confirm the relative importance and interplay between regional strike-slips and orthogonal displacement during basin development and deformation.The NE-SW-striking dominant rift basin indicates that the geodynamic drivers of tectonic evolution in the western margin of the South China Sea did not have a large strike-slip mechanism.Therefore,we conclude that a large strike-slip fault system did not exist in the western margin of the South China Sea.

关 键 词：Sedimentary basin Seismic sequence RIFTING Tectonic evolution South China Sea 

分 类 号：P534.4[天文地球—古生物学与地层学]