摘要
四川盆地西缘和北缘被前陆冲断带围限,各冲断带在构造演化和变形特征上具有明显的差异。龙门山前陆冲断带主要经历了两期明显的缩短变形:印支期和新生代,龙门山南段以新生代变形为主,以中—高角度基底卷入的叠瓦构造为特点,而北段以印支期变形为主,表现为低角度基底卷入的叠瓦构造。米仓山前陆冲断带主要经历了四期逆冲变形:印支期、中侏罗世早期、晚侏罗世—早白垩世及新生代,构造变形在平面上以叠加构造为特征,剖面上以中—下三叠统为界,滑脱层以下,基底卷入型冲断构造、反冲构造及断层相关褶皱较为发育,而在该滑脱层之上冲断构造和反冲构造不发育。大巴山前陆冲断带主要经历了三期逆冲变形:印支期、中侏罗世中—晚期及新生代,构造变形具有多层次滑脱的特点。由南西向北东,构造变形由以脆性为主逐渐转变为以韧性为主。
The west and north sides of the Sichuan Basin are adjacent to the fold—thrusts,which are different in tectonic evolution and deformation characteristic. The Longmenshan thrust belt experienced two major periods of crustal horizontal shortening in the Late Triassic and Cenozoic,the south segment experienced major deformation in the Cenozoic and forms mid—high angle basement-involved imbricate thrust structure,while the north segment experienced major deformation in the Late Triassic and forms low angle basement-involved imbricate thrust structure. The Micangshan thrust belt experienced four major periods of thrust deformation in the Late Triassic,early stage of Middle Jurassic,Late Jurassic—Early Cretaceous and Cenozoic. Superposition structure is familiar in field. Lower and Middle Triassic is the detachment layer,basement-involved thrust structure,back-thrust structure and fault-related fold are widely developed beneath the detachment layer, while these structures are rarely developed above the detachment layer. The Dabashan thrust belt experienced three major periods of thrust deformation in the Late Triassic,middle and late stage of Middle Jurassic and Cenozoic. The thrust belt is characterized by multi-level detachment structure. The structure is brittle deformation in major changed to ductile deformation in major gradually from SW to NE.
出处
《地质论评》
CAS
CSCD
北大核心
2015年第3期525-535,共11页
Geological Review
基金
国家自然科学基金资助项目(编号41102133)的成果
关键词
四川盆地
前陆冲断带
构造演化
变形特征
Sichuan Basin
fold—thrust belt
tectonic evolution
deformation characteristic
