库车坳陷东部秋里塔格背斜带的活动断层及其形成机制  

ACTIVE FAULTS AND THEIR FORMATION MECHANISM IN THE EAST SEGMENT OF QIULITAGE ANTICLINE BELT,KUQA DEPRESSION

作　　者：李胜强[1,2] 张玲[1] 杨晓平[1] 黄伟亮[1,3] 黄雄南[1] 杨海波[1] 

机构地区：[1]中国地震局地质研究所,活动构造与火山重点实验室,北京100029 [2]河北省地震局,石家庄050021 [3]长安大学,西部矿产资源与地质工程教育部重点实验室,西安710064

出　　处：《地震地质》2016年第2期223-239,共17页Seismology and Geology

基　　金：全国重点监视防御区活动断层地震危险性评价项目(1521044025);地震行业专项编制活动断层相关标准研究(201308001)共同资助

摘　　要：在详细调查盐水沟以东秋里塔格背斜带地质、地貌特征的基础上,结合地震反射剖面揭示的深部构造形态,讨论了背斜区地表断层的分布特征、活动性及形成机制。盐水沟以东的秋里塔格背斜带包括库车塔吾背斜和东秋里塔格背斜。库车塔吾背斜核部断层是发育于古近系盐膏层中的滑脱断层向地表的延伸,在晚更新世仍持续活动。库车塔吾背斜北翼断层为受局部挤压应力控制而产生的褶皱调节断层,发育于北翼山前活动枢纽内,成组近平行出现,走向上展布不连续;探槽开挖结果表明,该断层全新世有过断错地表的古地震事件。发育于东秋里塔格背斜南翼靠近核部的博斯坦断层为较大规模的低倾角逆冲断层,向下可能与控制表层背斜生长的断坡相连。东秋里塔格背斜南翼断层是发育于断展褶皱陡倾前翼的剪切逆冲断层,亦平行成组出现,断续分布,在哥库洛克一带断层错断了全新世洪积扇。活动褶皱及其褶皱相关断层均为深部断层滑动经过复杂的褶皱变形传播到近地表的表现,是深部断层活动的指示构造。褶皱调节断层仅是褶皱过程中产生的局部变形,与控制褶皱生长的深部断层仅存在间接的关系。此类断层的滑动位移、速率等不代表深部控制背斜生长断层的运动学参数,但这些次级断层部分记录了活动褶皱区的古地震事件。Based on geological and geomorphologic characteristics of the surface faults acquired by field investigations and subsurface structure from petroleum seismic profiles, this paper analyzes the distribution,activity and formation mechanism of the surface faults in the east segment of Qiulitage anticline belt which lies east of the Yanshuigou River and consists of two sub-anticlines： Kuchetawu anticline and east Qiulitage anticline. The fault lying in the core of Kuchetawu anticline is an extension branch of the detachment fault developed in Paleogene salt layer,and evidence shows it is a late Pleistocene fault. The faults developed in the fold hinge in front of the Kuchetawu anticline in a parallel group and having a discontinuous distribution are fold- accommodation faults controlled by local compressive stress. However,trenching confirms that these fold-accommodation faults have been active since the late Holocene and have recorded part of paleoearthquakes in the active folding zone.The fault developed in the south limb near the core of eastern Qiulitage anticline is a low-angle thrust fault,likely a branch of the upper ramp which controls the development of the eastern Qiulitage anticline. The faults lying in the south limb of eastern Qiulitage anticline are shear- thrust faults,which are developed in the steeply dipping frontal limb of the fault-propagation folds,and also characterized by group occurrence and discontinuous distribution. Several fault outcrops are discovered near Gekuluke,in which the Holocene diluvial fans are dislocated by these faults,and trench shows they have recorded several paleoearthquakes. The surface anticlines of rapid growth and associated accommodation faults are the manifestations of the deep faults that experienced complex folding deformation and propagated upward to the near surface,serving as an indicator of faulting at depth.The fold- accommodation faults are merely local deformation during the folding process,which are indirectly related with the deep faults that control the

关 键 词：活动断层 褶皱调节断层 逆断裂-褶皱带 东秋里塔格背斜 库车坳陷 

分 类 号：P315.2[天文地球—地震学]