龙门山断裂活动和川西高原隆升历史的裂变径迹测年  

TISSION-TRACK DATING FOR ACTIVITY OF THE LONGMENSHAN FAULT ZONE AND UPLIFTING OF THE WESTERN SICHUAN PLATEAU

作　　者：杨农[1,2] 张岳桥[1,2] 

机构地区：[1]国土资源部新构造运动与地质灾害重点实验室,北京100081 [2]中国地质科学院地质力学研究所,北京100081

出　　处：《地质力学学报》2010年第4期359-371,共13页Journal of Geomechanics

基　　金：科技部973课题"龙门山地质构造断裂带及其与汶川蕴震动力条件分析"(编号2008CB425702)的成果

摘　　要：通过12个构造岩、变质砂岩和花岗岩样品的磷灰石裂变径迹测年年龄分析,结合前人研究成果,初步确定了青藏高原东缘龙门山地区晚新生代主要断裂活动时期和区域隆升历史。结果表明,龙门山逆冲推覆构造带2条主断裂:汶川—茂县断裂和映秀—北川断裂,最晚一次强烈活动发生在早更新世(FT年龄为1.2～1.3 Ma),高原内部北西向米亚罗断裂在中更新世(约0.5 Ma)发生过强烈活动;后龙门山逆冲推覆构造带在中新世晚期开始快速隆升,而高原内部强烈隆升发生在上新世末至中更新世。高原隆升导致深切河谷地貌的形成和发育。Twelve samples of tectonites,metasediments and granites taken from the western Sichuan Plateau were dated in this study by apatite fission track dating method.The results are used to reconstruct uplifting history and fault activity of the Longmenshan tectonic belt in eastern margin of the Tibetan Plateau.It is shown that the recent activity of the two major boundary faults: theWenchuan-Maowen fault and the Yingxiu-Beichuan fault,occurred in early Pleistocene(FT ages of 1.2 ～ 1.3 Ma);the Miyaluo fault developed in the interior of the plateau was strongly active in middle Pleistocene(around 0.5 Ma);the back Longmenshan tectonic zone started to uplift in Miocene;and the interior of the plateau began rapid uplift in latest Pliocene to Middle Pleistocene.The uplifting of the plateau caused formation of deep-incised river morphology.

关 键 词：晚新生代 川西高原 龙门山断裂带 隆升 裂变径迹测年 

分 类 号：P542.3[天文地球—构造地质学] P546[天文地球—地质学]