Jinchuan Mining Ductile Shear Zone Characteristics And Its Significance

The study of ductile shear zone is one of the hot poits in tectonic geology recently. Moreand more people are focus on the ductile shear zone(DSZ). This article through to theJinchuan copper and nickel mining area geological1:10000geological survey, found anumber of ductile shear zone in Jinchuan copper and nickel mining area They are theimportant parts of the Alashan massif tectonic activities and evolution.The discovery andStudy of the ductile shear zone on the inversion of tectonic evolution has importantsignificance. Jinchuan deposit is located in the Longshou mountain fold belt of Alashan blockof the southern margin of the North China plate,it is the important copper nickel metalmineral resource place of production in our country’s, it is the third largest copper nickelsulfide magmatic ore deposit in the world. The tectonic framework and tectonic evolution ofLongshou mountain fold belt is controlled by the North China plate and Southern China plateconvergence evolution. The study area within the broader development of folds and faults,NW tectonic line is the main direction of deformation. The ductile shear belt in spacedistributs on North West, mainly distributed in the Sinian Dalin group and the late ProterozoicTamazigou group、Baijiazuizi group contact zone, It also distributs of rock mass on both sidesand Baijiazuizi group (difficult to identify). Macroscopical on expression is a series ofmylonite zone and competent schistositilization deformation belt. Research area on the southside can see without deformation for rock of continental facies Devonian almond shapedandesitic volcano rock.Mylonite fabric analysis that the region ductile shear zone experienced a three-stagecontinuous stress superposition transformation, kinematics and dynamics is characterized by:the early period was mainly the tensile stress which was from bottom to up. In the middleperiod, it was mainly right of pure shearing action which was NW-SE trend. At the lastperiod, the positive pressure accompanied by local press twist action which was NE-SW trend.At the same time, the maximum principal stress of the right of pure shearing action is NW-SEtrend. The positive pressure of the last period was NE-SW trend. According to the subgrain ofquartz, we can conclude its paleostress D-value was282.9MPa. According to the ductile shear zones in the strata distribution, combined with the Qilianorogenic tectonic evolutionary history, we concluded that the ductile shear structure in theregion with the formation of the Caledonian movement of the end of the Caledonianmovement fold return, the formation of the Devoniancontinental volcanic rocks. Tectonicdeformation in the Wa Lane West and beyond are shallow, brittle fracture and the broad andgentle folds superimposed deformation.