鄂尔多斯西南缘陇县-岐山断层构造地貌特征定量分析  

Quantitative Analysis of Morphotectonic Features of the Longxian-Qishan Fault in the Southwestern Margin of Ordos Block

作　　者：樊双虎 张天宇[2] 卢玉东[2] 陈淑娥[1] FAN Shuanghu;ZHANG Tianyu;LU Yudong;CHEN Shue(School of Earth Science and Resources,Chang’an University,Key Laboratory for the study of Focused Magmatism and Giant Ore Deposits,MLR,Xi’an 710054,Shaanxi,China;School of Water and Environment,Chang&apos,an University,Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region,Chang&apos,an University,Ministry of Education,Xi’an 710054,Shaanxi,China)

机构地区：[1]长安大学地球科学与资源学院,国土资源部岩浆作用成矿与找矿重点实验室,陕西西安710054 [2]长安大学水利与环境学院,旱区地下水文与生态效应教育部重点实验室,陕西西安710054

出　　处：《西北地质》2020年第2期60-76,共17页Northwestern Geology

基　　金：中国地质调查局“特殊地质地貌区填图试点”项目(DD20160060、12120114042101)。

摘　　要：陇县岐山断层位于青藏高原东北缘、鄂尔多斯地块及渭河盆地三者结合部位,既是青藏高原北东向扩展的前锋,也是海原六盘山断裂带与秦岭断裂系之间构造转换的桥梁与纽带。深入地认识其构造地貌特征、活动特性及动力学机制,有助于进一步揭示青藏高原北东向扩展机制及构造转换特征。基于30 m分辨率ASTER GDEM数据,利用定量构造地貌参数分析构造地貌特征及构造活动性差异,根据经验公式估算其垂直滑动速率,并结合断层运动学特征探讨了构造地貌演化的动力机制。根据断层山前带的线性特征,断层自西北向东南可以划分为7个次级段落,48个流域及31个山前面的地貌参数及估算的垂直滑动速率显示出断层东南部构造抬升强于西北部。综合分析认为,陇县岐山断层受青藏高原北东向扩展的远程影响,西北部以左行走滑运动为主;东南部受渭北隆起影响以构造抬升运动为主,且向西北方向翘倾。The Longxian-Qishan fault,located in the joint of the northeast of Tibetan Plateau,Ordos Block and Weihe River Basin,is the forefront to the northeast of the Tibetan Plateau,and also the linking between the Haiyuan-Liupanshan fault and the northern Qinling fault system.In-depth study of its tectonic geomorphic features,tectonic activities and dynamic mechanism is helpful to further understanding the NE extension mechanism and tectonic transformation of NE Tibetan Plateau.Based on 30m resolution ASTER-GDEM data,this article analyzed the structural geomorphologic features and tectonic activities by geomorphologic parameters,and estimated the vertical slip rate according to the empirical formula.The fault can be separated into seven geomorphic segments according to the linear feature of mountain fronts.Analysis of the extracted tectonic geomorphology index of 48 drainage basins and 31 mountain front facets and the estimated uplift rates reveal a general pattern of strong tectonic uplift in the southeast and weak tectonic uplift in the northwest.Combined with the above research results and the fault kinematics characteristics,the dynamic mechanism of tectonic geomorphologic evolution was also discussed.The above research suggests that Longxian-Qishan fault is affected by the northeastern extension of Tibetan Plateau and the northwest section of the fault is dominated by left-lateral strike-slip movement while the southeast is dominated by tectonic uplifting with a northwest tilting direction under the influence of Weibei uplift.

关 键 词：鄂尔多斯西南缘 陇县岐山断层 构造地貌 地貌指数 垂直滑动速率 

分 类 号：P542[天文地球—构造地质学]