摘要
通过野外地质考察和地震资料解释,将龙门山褶皱冲断带划分为5个构造带,即青川-茂汶断裂以西为松潘-甘孜构造带,青川-茂汶断裂与北川-映秀断裂之间为韧性变形带,北川-映秀断裂与马角坝-通济场-双石断裂之间为基底卷入冲断带,马角坝-通济场-双石断裂与广元-关口-大邑断裂之间为前缘-褶皱冲断带,广元-关口-大邑断裂以东为前陆坳陷带,在构造变形特征上,各条断裂在演化上具有前展式特征,在松潘-甘孜构造带和韧性变形带构造变形强烈,形成推覆构造带等构造变形样式,在前缘-褶皱冲断带和前陆坳陷带,变形强度较弱,形成背冲断块或断层相关褶皱等构造,西北部区域的变形表现为塑性变形特征,向南东方向渐变为塑-脆性变形和脆性变形,在剖面上各条断裂所形成的深度向盆地方向逐渐递减。龙门山褶皱冲断带的分带性变形特征是由多种因素共同影响的结果,这些因素主要有板块构造背景的决定作用、多套滑脱层的控制作用和岩性因素的制约作用。
Based on the geological surveying and seismic data, we divided the Longmenshan fold and thrust zone into five tectonic belts, that is, the Songpan-Graze tectonic belt to the west of the Qingchuan-Maowen fault, the ductility deformation tectonic belt between Qingchuan-Maowen fault and Beichuan-Yingxiu fault, the basement involution fold and thrust belt between Beichuan-Yingxiu fault and Majiaoba- Tongjichang-Shuangshi fault, the front fold and thrust belt between Majiaoba-Tongjichang-Shuangshi fault and Guangyuan-Guankou-Dayi fault, and the foreland depression belt to the east of Guangyuan-Guankou- Dayi fault. Each fault is tectonically characterized with piggyback propagation, with intense tectonic deformation in the Songpan-Graze tectonic belt and the ductility deformation tectonic belt where nappe structure were well developed. The tectonic deformation was weak in the front fold and thrust belt and the foreland depression belt where pop-up, fault related fold and so on were developed widely. While the northwestern area displays the features of a ductile deformation and gradually changes to ductile-brittle deformation and brittle deformation to the southeast. The depth of each fault decreased toward the basin from the seismic section. Zonation of Longmenshan fold and thrust belt was affected by many factors, the main factors of which are the tectonic setting, multiple decollement layers and lithology.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2007年第8期1072-1080,共9页
Acta Geologica Sinica
基金
国家自然科学基金项目(编号40672143
40472107
40172076)
国家"973"计划项目(编号2005CB422107
G1999043305)
石油天然气成藏机理教育部重点实验室开放基金项目(编号2003-03)
中石化西南分公司项目(编号GJ-51-0602)联合资助的成果
关键词
分带性变形
松潘-甘孜构造带
基底卷入冲断带
前陆坳陷带
龙门山褶皱冲断带
zonation deformation
Songpan-Graze tectonic belt
the basement involution fold and thrust belt~ the foreland depression belt~ Longmen Mountain
