岷江上游河流阶地对龙门山断裂带逆冲作用的响应  

River Terrace Responding to the Obduction of the Longmenshan Fault Zone in the Upper Min River Basin

作　　者：陈浩[1] 李勇[2] 

机构地区：[1]绵阳师范学院资源环境工程学院,四川绵阳621006 [2]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

出　　处：《山地学报》2014年第5期535-540,共6页Mountain Research

基　　金：国家自然科学基金资助项目(40841010)~~

摘　　要：汶川地震导致的岷江阶地面垂直错动量,记录了在地震这一突变性构造活动作用下水系的瞬时变化情况。震后野外实测数据表明,切过北川-映秀断裂的岷江阶地面,因断裂北西盘的逆冲作用产生了2.7 m的累积垂直位错量。若干次历史地震驱动的逆冲作用使切过龙门山主干断裂的岷江阶地面被大尺度垂直错断,根据阶面垂直扭错量和相应测年值计算可知,汶川-茂县断裂、北川-映秀断裂、彭县-灌县断裂晚第四纪以来逆冲速率分别为0.84 mm/a、0.52 mm/a和0.24 mm/a,计算结果表明,龙门山各主干断裂逆冲作用有自北西向南东减弱的趋势。龙门山各主干断裂的差异活动不仅使被断裂切过的岷江阶地面产生不同尺度的垂直变形,而且使汶川-茂县断裂和北川-映秀断裂所夹持的后龙门山地区的抬升速率和抬升幅度,大于北川-映秀断裂和彭县-灌县断裂所夹持的前龙门山地区。The instantaneous variations of water system was recorded by the vertical displacement of terraces surface caused by the Wenchuan earthquake,the field investigation data showed that the vertical slip amount of terraces surface of Min river reaches 2.7 m because of the thrust motion of Beichuan- Yingxiu fault.Terraces surface of Min river was vertically dislocated by Longmenshan main faults because of several times obduction.The thrust rate of faults was calculated according to the vertical slip amount of terraces surface and the corresponding age.The thrust rate of Wenchan- Maoxian fault is 0.84 mm /a,the thrust rate of Beichuan- Yingxiu fault is 0.52 mm /a,the thrust rate of Pengxian- Guanxian fault is 0.24 mm /a.The intensity of obduction of main faults in the Longmen Mountain were decreased from northwest to southeast.The uplift rate of back Longmenshan sandwiched between Wenchan- Maoxian fault and Beichuan- Yingxiu fault are faster than the uplift rate of fore Longmenshan sandwiched between Beichuan- Yingxiu fault and Pengxian- Guanxian fault because of the differential activity of Longmenshan main faults.

关 键 词：岷江上游 河流阶地 龙门山断裂带 逆冲作用 

分 类 号：P931.2[天文地球—自然地理学]