摘要
东天山至阿尔泰一带吸收了约10mm/a的地壳缩短量,占印度-欧亚大陆缩短量(约40mm/a)的^(1/4),其中一部分变形量在阿尔泰一带通过断裂的右旋走滑和块体的逆时针旋转的联合作用吸收,但东天山一带的地壳变形吸收和调节方式目前仍然存在争议。通过近年来在东天山东段碱泉子、巴里坤山和哈尔尼克山进行的野外地质调查工作,发现东天山东段展布1个左旋走滑断裂系。自西向东,碱泉子-托莱泉断裂、巴里坤盆地南缘断裂和哈尔尼克山中央断裂构成该断裂系的主要格架,这个断裂系在东天山晚第四纪乃至新生代以来的造山过程中调节了山脉隆升过程的变形分配。这些断裂的晚第四纪活动随着断裂走向与区域主应力(NE向)夹角大小的变化呈现不同的活动特征。具体来说,近EW向的碱泉子-托莱泉断裂展现出以走滑为主的特征,这种特征一直延伸到EW—NW向巴里坤盆地南缘断裂的雄库尔一带,但自洛包泉以东巴里坤盆地南缘断裂开始发育逆冲分量,在巴里坤县城以东断裂的活动则表现为逆冲伴随走滑,往东NWW—EW向的哈尔尼克山中央断裂则又呈现出以走滑为主的特征。断裂系的活动特征耦合在东天山东段的造山过程之中,调节和吸收了部分地壳变形,造山带根部断层的变形在造山过程中可能并不是唯一起决定性作用的释放方式。
As we all know,Eastern Tienshan and Altaid in central Asia accommodate ~ 10 mm/a crustal shortening,accounting for 1 /4 shortening between India and Eurasia（ ~ 40 mm / a）. A substantial portion of these deformations was absorbed in Altaid in the north through a combination of right-lateral strike-slip and counterclockwise vertical axis rotation of crustal blocks, but how the crustal deformation was accommodated in Eastern Tienshan is still in debate. Based on the field investigation in Jianquanzi,Barkol Tagh and Karlik Tagh in Eastern Tienshan in recent years,we identified a sinistral strike-slip fault system mapped in Eastern Tienshan. From west to east,the JianquanziTuolaiquan Fault（ JTF）,South Barkol Basin Fault（ SBF） and Central Karliktagh Fault（ CKF）constitute the tectonic frame of this large-scale fault system,which plays an important role in adjusting the strain distribution during the process of orogening in Eastern Tienshan in Quaternary even since Ceonozoic era. The fault system displays different late-Quaternary characteristics when its orientation changes with regional tectonic principal stress（ NE）. Specifically,the EW-trending JTF exhibits sinistral slip with little vertical component which can extend to Xiongkuer segment on EW-NW-trending SBF. The EW-NW SBF displays sinistral slip from east of Luobaoquanto,Barkol County and reverse slip with little horizontal component at east of Barkol County. In easternmost,the WNW-EW trending CKF shows sinistral slip with no obvious vertical motion. This fault system＇s activity coupled in the orogenic process of easternmost Tienshan,adjusting and accommodating a portion of deformation included in the orogenic process,and in turn we suggest that the deformation associated with range front fault in the orogen root may not be the only decisive way of deformation releasing.
出处
《地震地质》
EI
CSCD
北大核心
2016年第3期617-630,共14页
Seismology and Geology
基金
财政部项目“中国重点监视防御区活动断层地震危险性评价”(1521044025)资助
关键词
东天山
走滑断裂系
区域主应力
晚第四纪活动特征
Eastern Tienshan
strike-slip fault system
regional tectonic principle stress
late-Quaternary active characteristics
