| The Xiao-Qinling gold deposit is located in the south of the North China Craton.And it's the second largest gold deposit in China.The veins are mainly nearly east-west direction,northeast,north-south and north-west direction.The development of veins is controlled by the parallel shear deformation zone.Among the four group veins,nearly east-west direction shear zones have the largest number of auriferous quartz veins and they also have the largest scale reserves.Northeast veins have the second largest number of auriferous quartz veins,and their scales are only after east-west veins,more than north-south veins and northwest veins.In the early years,there are many studies on the characteristics of the east-west shear zones,especially in it structure and mineralization characteristics.But there is little research on structure and mineralization features about the northeast shear belts,the structure relations with east-west shear zones about who formed earlier is not clear.The northeast direction shear belts' dip is between 30 to 60 degrees,dip direction towards northwest and southeast.In accordance with its dips can be roughly divided into two groups,one is trending to north-northeast and it dip is about 70 degree and the other is trending to east-northeast,it dip is about 30 degree.The shear zones of the two groups have their own characteristics in the structural.North-northeast shear belts have 70 to 80 degree while east-northeast shear belts degrees are about 30.In mineralization characteristics,the mineral assemblage types and mineralization stages of the two groups are also slightly different.In this paper,the study of the northeast shear zones can explain some problems.By using the methods of structural geology and mineralogy,we do the research on their geometry,kinematics and dynamic characteristics.Besides,by observing the type of mineralization and mineral assemblage,doing the experiment with the collected samples,and thus to explore the mineralization stage and characteristics.By doing the research on the series of northeast shear belts,such as the vein 505,the vein 401,the vein 154,the vein 110,the vein 185,the vein 881,the vein240,about their structural and mineralization features on the surface and underground in mine,we get some conclusions,(1)The northeast trending shear zones can bedivided into east-northeast and north-northeast trending shear zones according to their structural characteristics,and they control the development of quartz veins in an echelon arrangement.The striking of east-northeast shear bands is trending towards northwest.The shear belts are dominated by thrust movement,and also have left-slip motion.And their formation is affected by the northwest pressure on the region.The striking of north-northeast shear bands is trending towards southeast and northwest.The shear belts are dominated by left-slip movement,and also have thrust motion.And their formation is affected by the north-northwest pressure on the region.(2)Mineralization characteristics of east-northeast trending veins are mainly in pyrite mineralization.And the mineralization is in bands or along with the structure planes.The hydrothermal stage belongs to the second stage,which is quartz-pyrite mineralization stage.And the deposit is a middle high temperature deposit.Mineralization characteristics of north-northeast trending veins are mainly in sulfur polymetallic mineralization.And the mineralization is in bands or along with the structure planes.The hydrothermal stage belongs to the third stage,which is quartz-sulfur polymetallic mineralization stage.And the deposit is a middle high temperature deposit. |
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