摘要
钱营孜矿井位于淮北煤田宿县矿区的西部,毗邻徐宿弧形推覆构造南段的外缘带.为认识该矿井构造变形与演化规律、动力学机制以及指导未来资源探采方向提供重要地质依据.利用最新的矿井地质勘探与生产资料,对钱营孜矿井开展构造格架和控煤构造样式分析,划分矿井构造期次,讨论构造发育的区域大地构造背景.结果表明,矿井内石炭纪-二叠纪含煤地层总体呈一轴向NNE、向SSW仰起的宽缓向斜;矿井内断裂构造非常发育,逆断层数量大于正断层,2类断层的走向均以NE至NNE向为主,其次为NS向;矿井构造格架显著受控于数条NS向至NE向的大型断层,自西向东受南坪断层、F22、F17、DF200及双堆断层等主干断层的分割,呈现东、西分带特征;矿井控煤构造样式可以划分为挤压、伸展和走滑3个类型,以及逆冲牵引褶皱、对冲式构造、冲起构造、叠瓦状构造、地堑、地垒、阶梯状断层、正花状构造、羽状雁列式构造9个亚类型;构造组合分析表明,F17断层除逆冲活动之外,还存在显著的平移活动.矿井构造可划分为5期,从早到晚分别为:轴向NNE的冯家向斜、近NS向逆断层、NNE向逆-左行平移断层及NE向逆断层、近NS向正断层、NE向正断层.矿井内第1,2期缩短构造分别是印支期华北克拉通与华南板块汇聚过程中的前陆变形及随后陆-陆碰撞造山变形的影响结果;第3期压扭性构造与西太平洋区伊泽奈崎板块早白垩世初向东亚大陆边缘快速斜向俯冲有关;第4,5期伸展构造则是早白垩世以来中国东部强烈伸展背景下发育而成.
Abstract
The Qianyingzi Coalmine is located on the west of the Suxian Mining area of the Huaibei Coalfield,adja-cent to the outer edge of the southern segment of the Xu-Su Arc Nappe Belt.[Methods]Based on the latest geo-logical exploration and production data,this paper analysed the structural framework and coal-controlled structural patterns of the Qianyingzi Coalmine,divided the tectonic stages,and discussed the geotectonic background of the coalmine structures,[Objective]which provides an important geological basis for the understanding of the tectonic deformation and evolution of the coalmine,the geodynamic mechanism and the prediction of exploration directions.[Results]The results show that the Carboniferous-Permian coal-bearing formations in the mine are generally a gen-tle syncline with an NNE-trending axis.The faults in the mine are well developed,and the number of reverse faults is greater than that of normal faults.Both of these faults are mainly NE to NNE,followed by NS.The structural framework of this mine is significantly controlled by several large NS to NE-striking faults and is segmented from west to east by major faults,including the Nanping,F22,F17,DF200 and Shuangdui faults,which exhibit the char-acteristic of east and west zonation.The coal-controlled structural patterns in the mine can be classified into three types,namely,compressional,extensional and strike-slip.And the coal-controlled patterns can be further divided into nine subtypes,namely,thrust drag folds,hedge structures,pop-up structures,imbricate structures,grabens,horsts,step faults,positive flower structures and pinnated en-echelon structures.The analysis of structural combi-nations shows that the F17 fault has not only thrusting motion but also significant transcurrent activity.[Conclu-sion]The structural deformation of coal-bearing formation in the Qianyingzi Coalmine can be divided into five sta-ges:the Fengjia Syncline with an NNE-trending axis,nearly NS-striking reverse faults,NNE-striking reverse-sinis-tral faults and NE-striking reverse faults,nearly NS-striking normal faults,and NW-SE-striking normal faults.Combined with the results of previous studies on the regional tectonic background,the first and second shortening structures in this mine are the results of foreland deformation during the convergence of the North China Craton and South China Plate and subsequent continent-continent collisional deformation during the Indosinian period.The third stage compresso-shear structures are related to the rapid oblique subduction of the Izanagi Plate toward the East Asian continental margin at the beginning of the Early Cretaceous in the Western Pacific.The fourth and fifth stage extensional structures developed against a strong extensional background in eastern China during the Early Cretaceous.
维普
万方数据