新疆西准噶尔晚古生代以来构造样式与变形序列研究  

Structural style and deformation sequence of western Junggar, Xinjiang, since Late Paleozoic.

作　　者：徐芹芹[1] 季建清[1] 龚俊峰[1] 赵磊[1] 涂继耀[1] 孙东霞[1] 陶涛[1] 朱自虎[1] 何国琦[1] 侯建军[1] 

机构地区：[1]北京大学地球与空间科学学院,造山带与地壳演化教育部重点实验室,北京100871

出　　处：《岩石学报》2009年第3期636-644,共9页Acta Petrologica Sinica

基　　金：国家重点基础研究发展计划项目(2007CB411300、2001 CB409802);国家自然科学基金项目(49872078)资助成果.

摘　　要：断裂构造的发育是不同地质历史、不同应力场条件下地壳应变的叠加。针对某一地域断裂构造的研究,理清其发育序次和不同阶段断裂系统对应的构造应力场,是了解区域大地构造性质演变的重要环节。新疆西准噶尔地区构造运动和岩浆活动非常强烈,是认识中亚构造域性质的重要研究基地,同时也为断裂构造和变形序次研究提供了很好的野外实验室。通过对研究区1500个构造面理产状数据的统计与分析,认为新疆西准噶尔地区主要发育以下几组构造面理:(1)290°走向;(2)10°～20°和80～90°走向;(3)40°～45°和320°～325°走向;(4)60°～70°和340°～350°走向。通过对野外构造现象、断裂之间的交切关系、断裂与相关地层及岩体的切割关系等的综合分析,结合遥感图像解译,确立了走滑断裂是西准噶尔地区晚古生代以来主要的构造样式,并建立了相应的变形序列:(1)大约在二叠纪晚期一三叠纪,由于准噶尔与中天山汇聚末期的区域性水平运动,受到北西-南东向的挤压应力作用,发育最早一期北西西向(290°左右)右旋走滑断裂;(2)侏罗纪—白垩纪,地层产状平缓,没有发现区域性构造变形证据;(3)古近纪,主要受制于太平洋构造域,受到北西-南东向挤压应力作用,发育北北东向(10°～20°)左旋与近东西向(80°～90°)右旋共轭走滑构造;(4)新近纪早期,受印度大陆和欧亚大陆碰撞的远程效应影响,应力场为近南北向,发育北东向(40°～45°)、北西向(320°～325°)走滑构造,新近纪晚期应力场发生了小角度顺时针旋转,构造形迹又转变为北东东向(60°～70°)和北北西向(340°～350°)。A fault is superposition of crustal strain in different geological history and stress fields. Finding out the development sequence and tectonic field is very important for understanding the tectonic evolution. Because of intense tectonic process, the western Junggar of Xinjiang is riot only a good field laboratory for studying faults and deformation sequence, but also a key area to Understand the tectonic domain in central Asia. The statistics and analysis of 1,500 occurences show that the following four groups of structural foliation have developed: (1) WNW 290 degrees; (2) NNF. 10 degrees similar to 20 degrees and EW 80 degrees similar to 90 degrees; (3) NE 40 degrees similar to 45 degrees and NW 320 degrees similar to 325 degrees; (4) ENE 60 degrees similar to 70 degrees and NNW 340 degrees similar to 350 degrees. Based on analysis of field structures, intersection and cutting relationships of faults, intrusions and strata, combining with remote sensing data, it is concluded that the strike-slipping fault is the main structural style in western Junggar since Late Paleozoic, and the deformation sequence is also determined. During Late Permian to Triassic, the earliest dextral faults striking WNW 290 degrees were developed due to the NW-SE. direction compressive stress derived by the convergence between the Junggar and the central Tianshan. During Jurassic-Cretaceous, the tectonic process was relatively stable. The conjugated strike-slipping structures with sinistral faults striking NNE, 10 degrees similar to 20 degrees, and dextral ones trending EW 80 degrees similar to 90 degrees had developed in Paleogene maybe due to the NW-SE compressive stress from the Pacific tectonic domain. In Early Neogene, the direction of stress field was nearly north-south as a result of the. distant effect of collision between the Indian and the Eurasian continents, which resulted in the strike-slipping faults striking NE 40 degrees similar to 45 degrees and NW 320 degrees similar to 325 degrees. For the clockwise rotation of stres

关 键 词：晚古生代 走滑断裂 变形序列 西准噶尔 

分 类 号：P542.3[天文地球—构造地质学]