韩城矿区南部断层构造特征及控煤意义  

Structural characteristics of faults in southern Hancheng mining area and significance of coal control

作　　者：范玉海[1,2] FAN Yu-hai(Coal Aviation Geological Exploration Institute,China Coal Aerial Survey and Remote Sensing Bureau,Xi'an 710054,Shaanxi,China;Yulin University,Yulin,Shaanxi 719000,China)

机构地区：[1]中煤航测遥感局煤航地质勘查院,陕西西安710054 [2]榆林学院,陕西榆林719000

出　　处：《地下水》2022年第4期134-138,160,共6页Ground water

基　　金：国家科技重大专项(2008X05025-006);国家重点基础研究发展计划“973”项目(2015CB453000);国家自然科学基金(U1261111);陕西省第三批地勘基金项目(61201203093)。

摘　　要：鄂尔多斯盆地是位于华北克拉通西部的侏罗-白垩纪沉积盆地。韩城矿区地处鄂尔多斯盆地南缘渭北断隆铜川-韩城断褶带东部边缘,煤炭资源储量较大,且中、深部区煤层气资源前景可观。对地表精细观测的基础上,利用二维地震勘探技术,辅以钻探工程验证,在韩城矿区南部新发现一南北向隐伏逆冲构造(F2),呈西倾东冲,断面倾角为20°~35°,断于石盒子组内和下伏含煤岩系及其基底内,地层垂直断距为190~260 m,水平断距260~470 m。浅部表现为同向展布的不对称背斜构造。二者空间上密切共生,几何学和运动学具相关性,成因上具统一性,浅层背斜构造是深层逆冲作用控制下断展褶皱作用的结果。隐伏逆冲构造(F2)的形成机制是燕山运动期盆地内部因阻抗来自东侧构造挤压应力,而产生的反向逆冲构造作用响应,具有反断层性质。该逆冲构造错断煤层,造成煤层重复,控制了煤层的空间分布,构成为韩城矿区南中深部重要的构造边界。The Ordos Basin is a Jurassic-Cretaceous sedimentary basin located in the western part of the North China Craton.Hancheng mining area in the Weibei coalfield is located at the eastern margin of the Tongchuan-Hancheng fault–fold belt,a component ofthe Weibei faulted uplift atthe southern margin of the Ordos Basin.The coal reserves of the mining area are large,and there are considerable prospects for coalbed methane resources in its middle and deep regions.Detailed surface observation,2 D seismic exploration,and verification via drilling have revealed the presence ofan N-S hidden fault(F2)in the south of the Hancheng mining area.The results show that thisdeep hidden thrust fault dips to the west and has been thrusted to the east and that the dip of the fault plane is 20°~35°.The faulting penetrates the Shihezi Formation,underlying coal-bearing measures,and their basement.The vertical throw and the horizontal displacement were found to be 190~260 and 260~470 m,respectively.The shallow strata forma unidirectional asymmetrical anticline.The shallow anticline and hidden fault F2 are closely associated in space,interrelated in their geometry and kinematics,and unified in their genesis.The shallowanticlineis the result of fault-propagation folding under the control of deep overthrusting.Hidden fault F2 formed through reverse thrusting and tectonic deformation in response to compressive stress from the east side of the basin during the Yanshanian period has obvious recoil fault properties.The thrust fault dislocated coal seams,led to seam repetition,controlled the spatial distribution of coal seams,and constituted an important tectonic boundary in the middle and deep regions of the south part of Hancheng mining area.

关 键 词：隐伏断层 二维地震 断弯褶皱作用 渭北石炭二叠纪煤田 韩城矿区 鄂尔多斯盆地 

分 类 号：P542.31[天文地球—构造地质学]