Morphological And Dynamical Analysis Of Geological Structure Of Ximing Study Area In XiShan Coal Field Of Taiyuan

Located in northeastern of JinZhong basin, west of TaiYuan city, and in northwest QinShui coal field, TaiYuan Xi’Shan coal field is one of the six big coal fields of ShanXi province and important coal resources base of our country. Geologists have done a lot of work about structural analysis of XiShan coal field and obtained plenteous achievements. The coal field is a syncline which is broad and gentle in the east wing and steep in the west wing. Tectonic of YanShan period formed the frame of coal field, and the following multi-phase tectonic made its configuration complex. Though much work have been done, research related to the formation mechanism in the deep is rare. To complete the structural analysis of Xishan Coalfield, lots of work still remains to be done.The paper selects about20Km2area near Ximing mine of Xishan coalfield, which is between Duerping and Wangfeng horst-shape fault belts as the object of study. And the study area belongs to the Ximing and Duerping mine. It provides much more convenience for the contrast study between ground and underground for the abundant geologic data gathered during the underground coal mining process.Through scrutinizing of outcrop finding out the structure configuration problems in the area, making kinematics analysis and three-dimension geological blocks division using analysis method of structure interpretation. There are thirty-two normal fault in study area and the trends are various, main trends of structures are NE、NNE、NNW or near NS, E-S and NW. Faults of NE distribute in the middle of study area though small quantities(6in numbers), among these Fl and F2are the first grade structures which is big in displacement and long in extended distance. There are10faults in NNE and five of them inclined to southeast and spread as step-fault in the east of study area. There are seven faults whose trend is near NS distribute in the middle、south and north. There are two faults whose trends are east-west distribute in the south and southeast of study area. There are seven faults whose trends are NWW, five of them presents as step-faults to south, and two of them developed along YuMen gully and the south girder of YuMen gully. Besides, an outcrop of a reversed fault which reflected local extrusion stress is found at the west of the mountain girder between ShiTou house and TaiGu highway.The study area was divided into five first-order blocks on the basis of morphology and kinematics:East Block, North Block, Central Block, South and West Block. The East Block, which can be divided into two sub-level blocks:E1Block and E2Block, according to the movement property and the occurrence of rocks, is located in the eastern margin of the study area. The E1Block performs a movement toward the southeast direction with the strata generally east inclining, and part of the fault block is of big angle inclination; whereas, the E2Block moves toward northwest with the strata west inclining. There are compressive stress characteristics between the two blocks. The North Block performs fault depression toward north-north-west as a whole and followed by tectonic movement which made it become three sub-level blocks:N1Block, N2Block and N3Block. Among these blocks, the strata of N1Block are mainly inclining towards east-west with gentle dip and the block faults towards south; whereas, the strata of N2Block are of southeast inclining and the tectonic movements are not well developed; there is a north-east-east synform break-fault rifting toward southeast. The Central Block is the main body of the horst with a south-north to north-north-west fault and can be divided into two sub-level blocks based on the southward inheritance of the block boundary between N2and N3:C1Block and C2Block. The C1is inclining toward southeast with a pair of horsts rifting to east and west within the block; there are not any tectonic movements within the C2Block and the strata are inclining toward west or northwest. The South Block is rifting toward southeast with strata inclining to southeast in general. Moreover, the West Block is rifting toward west and the dip angle of the strata are also west.Like faults, collapse columns are major geological problems which affect both security and efficiency in the process of coal mine production. Theoretically, the formation of collapse columns need some material conditions. Collapse columns of XiShan coal field have C-L double-lawyer material basis, and fissure zones produced by structure activities provide channels for the supply and migration of groundwater. So the spatial distribution of tectonics and collapses have relationships. Conclusions from the contrast of identified tectonic distribution、collapse columns distribution of both field revealed and found in coal mine production all support theory analysis in the article.