峨眉断块山的形成  

Study on the Formation of the Emei Faulty Block Mountain

作　　者：王运生[1] 王登攀[1] 王奖臻[1] 傅荣华[1] 杨艳娜[1] 

机构地区：[1]成都理工大学灾害防治与地质环境保护国家重点实验室,成都610059

出　　处：《南水北调与水利科技》2013年第1期110-114,121,共6页South-to-North Water Transfers and Water Science & Technology

基　　金：国家自然科学基金"深切河谷强震作用下谷坡地震动响应监测研究"(41072231);中国地质调查局项目"汶川地震地质灾害调查评价--川西深切河谷斜坡地震动评价技术研究"(1212010914010)

摘　　要：峨眉山为一断块山,因其宏伟、秀丽而著称,但峨眉断块山是如何形成的,缺乏系统深入的研究。基于1∶25 000工程地质测绘,较为系统地研究了峨眉山地质构造形迹及构造叠加特征,认为峨眉山抬升始于古近纪晚期,喜山运动第一幕(始新世中期末)峨眉山受青藏高原隆升的影响,在北西西-南东东向区域应力场作用下,形成北北东向褶皱及北东向断层,并上升成为剥蚀区。上新世以来,在近东西向区域压应力场作用下,钝锥形大峨山断块沿北东向峨眉山断层及北缘的北西向边界断裂不断向东强力楔入,断块前缘早期的北北东向构造受推挤,地层走向及倾向出现明显偏转:锥顶前方龙门洞-报国寺一带地层由早期的北北东走向倾南东的中生代地层转为南北走向,地层出现倒转(西倾),而远离断块端部的地层仍然为正常产状。与此同时,锥顶北侧尖尖石背斜发生移褶,形成北西向褶皱和断层,而断块南侧峨眉山断层发生逆冲兼走滑活动。第四纪以来峨眉山间歇性强烈抬升,经历至少10次强烈抬升事件,逐渐形成现今地貌。新生代以来,峨眉山断层两盘地层水平位错累计达4km,垂直位错累计达6km。The Mt. Emei is a faulty block mountain, which is famous for its great and beautiful scenes, but its formation is lack of systematic studies. Based on the engineering geologic mapping of 1：25000 scale, the geological structure features and characteristics of structural superposition are systematically studied in this paper. The uplift of Mt. Emei began in the end of the Eocene, i. e. , during the Himalayan movement of the first epoch, under the pressure of NWW-SEE regional geo-stress, the NNE strike folds and NE faults have been formed and uplifted and became the erosion area. Since the Neocene, under the regional pressure of nearly EW geo-stress field, the blunt-cone Daeshan faulty block was wedging eastward along the NE Emei mountain faults and the NW boundary faults on the northern margin,and the early NNE strike strata of the block frontier bent anti-clockwise, resulting in diversion of the strike and dip direction of strata. The strike of the strata in the frontier area （Longmendong-Baogu- osi） varied from the early leaning NNE towards SE to SN,and the strata dip westward,while the strata far away from the block frontier was still in normal attitude. The Jianjianshi anticline bent eastward in the north boundary of the block, forming the NW folds and faults,while the Emei mountain fault slipped in the south boundary of the block. Since the Quaternary, the intensive intermittent uplift occurred for the Emei mountain, and the current topography was formed due to more than 10 uplifting events. Since the Cenozoic, the horizontal dislocation between two strata of the Emei mountain fault is about 6 000 m, while the vertical dislocation is 4 000 m.

关 键 词：大峨山断块 构造特征 新生代 构造叠加 演化程式 

分 类 号：P541[天文地球—构造地质学]