Fracture Structure Periodization And Ore Controlling Regularity Of Hengyang Qingshuitang Lead-Zinc Mine Area In Hunan Province

Qingshuitang was a medium-sized non-ferrous metal mine that abounds in lead,zinc, silver, tin and other elements in middle Hunan. The ore field located in the fault zone headed from NE to NNE. Qingshuitang lead-zinc mine area, including deposit Qingshuitang,Fengmuchong,Chuangtianling and Shao Dong Liemazhai,covered an area of nearly 40km2.The paper taked Qingshuitang lead-zinc mine area as the research object, on the basis of studying the regional metallogenic geological background, typical ore deposit geological characteristics, to investigate the fracture structures distribution characteristics, tectonic ore-controlling regularity, fracture structures periodization,and Metallogenic evolution process.Accordingly,illustrated the fracture structure distribution characteristics and ore-controlling regularity of different period in mine area, and sums up the tectonic evolution and metallogenic process in mine area,provide a reference basis for the search of new lead-zinc deposits.The main achievements of this paper are as follows:1.Study considered the regional tectonic movement is divided into three period:Yangzi-Caledonian period, Hercynian-Indosinian period, Yanshan-Himalayan period, In these three structure period developed three formations and fold, fault structure system accordingly.2.The study found that within the mine area developed five groups of fractures headed to NE,NNE,NW,NWW and NEE,and has a characteristics of multiphase tectonic activities evolution, means the area experienced multiphase tectonic activities since the sedimentary rock,formed the structure of the existing structure.3.According to the relationship between the fracture and mineralization,considered the fracture in the area can be divided into three periods:fracture before metallogenic,fracture after metallogenic and fracture at metallogenic. According to the cut through relationship between the vein and fracture and the sample analysis of mining, considered that fracture before metallogenic mainly distributed in the northwest of the mine area,mostly headed to NWW and NEE, fracture at metallogenic mainly distributed in eastern and southern of the mine area,mostly headed to NE,fracture after metallogenic are distribution in the hole mine area, fracture after metallogenic mostly headed to NW in the eastern mine area, fracture after metallogenic mostly headed to NE in the western mine area,embodies two different period of fracture after metallogenic.4. Research on tectonic stress period of the ore deposit and combined with thecomprehensive analysis of actual situation of existing exploration engineering had improved that, early main compressive stress under the action of formation of the NE trending fracture mainly controlled the ore bodies in space distribution and output,Since then formed under the action of tectonic stress nearly EW trending interlaminar fracture and nearly NS trending fault on the early formation of the NE trending to fracture tectonic system has a certain composite superimposed reformation, at last the early principal compressive stress direction translated into tensile stress orientation, they were in an opposing relationship both in time and space, and the late tectonic stress field stress azimuth change significantly in the middle, Showed the characteristic of faulting and reverse.5. In the metallogenic evolution process of Qingshuitang lead-zinc mine, the fault structure played an important role in controlling the mineralization of leadzinc, present some following regularities :(1) deep fracture controlled the spatial distribution of the ore body as the conducting structure;(2) subsidiary fracture controlled the enrichment part of lead-zinc mineralization as the ore bearing fracture;(3)fracture at metallogenic had good ore-bearing potential, controlled the form and attitude of ore body and enrichment part of mineralization;(4) fracture before metallogenic and fracture after metallogenic had bad ore-bearing potential;(5)the intersection part of ore bearing fracture tectonics in different direction had the best ore-bearing potential.