Study On The Metamorphic And Deformation Characteristics Of The Typical Deposit In The Shanxi Mt.Wutai-Hengshan Iron Mine

The paper based on the project"Shanxi Mt.Wutai-Heng area's basic geological research".Selecting the typ ical iron ore of deposit area of the Chuyugou,and Yangjiaogou as the research object.Using the Plate tectonics theory,activity theory and modern metallogenic theory as the guide line.Using structural analysis and structural comparison method.The main line is the study of surface structure and drilling core structural rock zoning.Based on the metallogenic chronology.Based on lithology geological mapping.Comparison division the structure,rock and stratum.Build the form of regional structure rock and stratigraphic framework and do structural deformation analysis.Summing up the development and metallogenic age of fold and fault structure zone.In order to provide a reference for the analysis of the reservoir forming conditions,metallogenic regularity and tectonic evolution characteristics of the iron ore deposits in the study area.Understanding and development:1.Chuyugou study area has large scale Lu Shi Ju subsets of the Xiyan phyllite,metamorphic sandstone,magnetite quartzite,very small amounts of plagioclase amphibolite,Wang Zhuang group sericite chlorite phyllite,Jin Gang group library sodium long chlorite phyllite,Juan Yun quartz schist,and Ekou granite-gneiss.So the research area has experienced more than three tectonic deformation.Wutai movement first act(D_I)mainly tectonic;Wutai movement of the second act(D_II)is also very strong,strong improvement on main structure and large-scale superimposed deformation;Wutai movement in the third act(D?)Juya group is relatively weak in the earlier fold to further compress and ductile fracture of further activities,reflecting the strata experienced many tectonic changes by the anisotropic tend to isotropic,gradually stable characteristics..2.Yangjiaogou study area large scale terrace Wyatt group Baizhiyan phyllite,metamorphic sandstone,magnetite quartzite,very small amounts of plagioclase amphibolite,part of Hongmenyan quartz schist,and metamorphosed diabases,metamorphic basalt.So in the study area is mainly undergone the second act above the tectonic deformation,Wutai movement of the second act(D_II)mainly tectonic,deformation of late plays an obvious control effect;Wutai movement,the third act(D?)deformation is relatively weak,of strata in the study area the superposition of different degree of deformation.3.Isotopic years results and characteristics of the zircon shows,the Wutai Group rock to rock age not early in about 2.5Ga,experience the multi-stage geological evolution,at least 4 metamorphic event:more than 2.4Ga,central subduction orogeny occurred and the end of the,the subsequent large-scale continental flood basalt eruption,the mainland extensional collapse;about 2.3Ga and from 2.1Ga to 2.2Ga,respectively have two regional tectono thermal events occurred;from 1.8Ga to 1.6Ga,continental blocks cleavage,large-scale mafic dykes form.Multi stage metamorphism is a necessary condition for a large ore deposit in this area.