龙门山断裂带走滑方向的反转及其沉积与地貌标志  

GEOMORPHIC AND SEDIMENTARY EVIDENCE FOR REVERSION OF STRIKE-SLIP DIRECTION IN LONGMEN SHAN FAULT ZONE

作　　者：李勇[1] 周荣军[2] A L Densmore M A Ellis 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [2]四川省地震局工程地震研究所,四川成都610041 [3]Institute of Geology Department of Earth Sciences ETH Zentrum [4]Center for Earthquake Research and Information,University of Memphis

出　　处：《矿物岩石》2006年第4期26-34,共9页Mineralogy and Petrology

基　　金：国家自然科学基金项目(编号49803013;40372084);高等学校博士学科点专项科研基金项目(编号20050616004);四川省重点学科建设项目(编号SZD0408);中国石油化工公司重大前瞻性研究项目(G0800-06-25-282)

摘　　要：根据龙门山前陆盆地西缘沉降中心、冲积扇侧向迁移、活动构造地貌和古地磁等标志及龙门山在中生代以来的走滑作用和走滑方向的标定研究,结果表明:龙门山断裂带具有走滑性质,走滑方向曾发生过反转,在反转之前以左行走滑作用为特征,在反转之后以右行走滑作用为特征。根据地层记录和古地磁证据,认为龙门山走滑方向反转的时间应介于43 M a^3.6 M a之间,即由中生代至早新生代时期的左行走滑作用反转为晚新生代时期的右行走滑作用。然对龙门山断裂带走滑方向反转的成因初步分析认为晚新生代龙门山右行走滑作用是印-亚碰撞后构造作用的产物,晚三叠世至早新生代左行走滑作用是青藏高原自晚三叠世以来大陆碰撞作用导致松潘-甘孜褶皱带北东-南西向缩短的产物。Based on the evidence of migration of the depocentre and fan in the foreland basin,the active tectonics ,geomorphy and paleomagnetism from Mesozoic to early Cenozoic and later Cenozoic,the direction of strike-slip faulting has been reversed from sinistral strike-slip in Mesozoic and early Cenozoic to dextral strike-slip in the later Cenozoic. According to stratigraphy and paleomagnetism,the reversion of the strike-slipping direction in Longmen Shan fault zone happened during 43 Ma to 3.6 Ma. It was considered that the dextral strike-slip in the later Cenozoic is due to the effect of post-India--Eurasian collision,and the sinistral strike-slip in Mesozoic and early Cenozoic is due to the effect of shorting of Songpan-Ganzi Fold Belt driven by accretion of the Cimmerian continents and the India/Eurasia collision.

关 键 词：走滑作用 沉积标志 地貌标志 走滑方向反转 中新生代 大陆碰撞作用 龙门山 青藏高原东缘 

分 类 号：P315.5[天文地球—地震学]