摘要
本文对穿过南海西南次海盆的逾1000 km的多道地震测线CFT剖面进行了地震界面特征的识别和地震层序的划分,分段分析了拆离断层对其减薄陆壳的拆离作用。结合前人研究成果,对南海西南次海盆地壳结构特征开展了分析,并总结了其构造特征。西南次海盆在发生陆缘张裂—海盆扩张、洋壳出现—扩张后稳定沉积这一系列过程中,可划分为4个阶段的沉积响应:A阶段(古新世之前)——前裂谷阶段,表现为地壳在拉张应力下产生小的断层;B阶段(始新世—早渐新世)——陆缘的裂谷阶段,地壳在拉张应力下拉张减薄,A阶段产生的断层出现了旋转,出现了大型掀斜的拆离断层,沉积物为同裂谷沉积,该阶段以产生了破裂不整合结束;C阶段(晚渐新世—早中新世)——海盆扩张阶段,海盆开始扩张,张应力从陆缘转移到了洋盆;D阶段(中中新世以来)——海盆扩张结束以后,以一套稳定沉积为特征。
In this paper,the authors analyzed over 1000 kilometers’multi-channel seismic line(the CFT profile)across the southwestern subbasin of the South China Sea,with identification of seismic interface characteristics and seismic sequence division,and analyzed the detachment effect of detachment faults on the thinning of continental crust in segments.On the basis of the previous research results,an analysis of the crustal structure characteristics of the South China Sea was carried out,and its structural characteristics were summarized.The southwest sub-basin can be divided into four stages of sedimentary response during the series of continental marginal rifting and sea basin spreading and post-expansion:Stage A was the pre-rift stage,showing that the small faults was generated under tensile stress;Stage B was the rifting stage,when the crust of continental margin was thinning in the tensile stress,the fault generated in Stage A was rotated,and the large tilting detachment fault appeared.The sediments were the synrift deposits,and this stage ended with the breakup unconformity;Stage C was the basin expansion stage,during which the sea basin began to expand and the tensile stress shifted from the continental margin to the ocean basin;Stage D was the post-spreading stage,after ending of the basin expansion,the sediments were a set of stable deposits.
作者
聂鑫
邱燕
Manuel Pubellier
汪俊
朱荣伟
杜文波
NIE Xin;QIU Yan;MANUEL Pubellier;WANG Jun;ZHU Rongwei;DU Wenbo(Guangzhou Marine Geological Survey,China Geological Survey,Key Laboratory of Marine Resources,Ministry of Natural Resources,Guangzhou 51760,Guangdong,China;Southern Marine Science and Engineering Guangdong Laboratory,Guangzhou 511458,Guangdong,China;Laboratoire de Géologie,Ecole Normale Supérieure,C.N.R.S.UMR 8538,24 rue Lhomond,Paris 75231,France)
出处
《中国地质》
CAS
CSCD
北大核心
2020年第5期1463-1473,共11页
Geology in China
基金
南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0207)
中国地质调查局项目(DD20160138、DD20190627、DD20190209、DD20191002、GZH201400203)
国家自然科学基金委员会-广东省联合基金重点项目(U1901214)
国家自然科学基金项目(41572083、41606080)联合资助。
关键词
CFT剖面
破裂不整合
洋盆扩张
沉积响应
西南次海盆
海洋地质调查
南海
CFT profile
breakup unconformity
ocean basin expansion
sedimentary response
southwest subbasin
marine geological survey
South China Sea
