Geological Characteristics And Genesis Of Caiyuanzi Gold Deposit In Muli County,Sichuan

The Geotectonics of Caiyuanzi gold deposit is located in the south section of Ganzi Litang structural belt.This structural belt is an important non-ferrous and precious metal metallogenic structural belt in the Western Sichuan.As a gold deposit with certain metallogenic potential in the structural belt,Caiyuanzi gold deposit is studied and discussed in this paper on the basis of previous studies,By means of mineralogy,petrology,mineralogy and geochemistry,the genesis of the deposit is summarized and the metallogenic model is defined.The ore body of Caiyuanzi gold deposit mainly occurs in the metamorphic rocks of the middle devonian caina formation,The ore-bearing strata are mainly the first and second sections of the Cangna formation in the middle devonian system,The ore bodies mainly occur in carbonaceous phyllite and sericite phyllite and are controlled by fault structure,They are mainly pinnate and lenticular in the vicinity of tectonic faults.The main ore minerals are pyrite and chalcopyrite;The main gangue minerals are quartz sericite and dolomite.Hydrothermal alteration is frequent in the mining area and there are many types of alteration,The main types of alteration are silicification,sericitization,pyritization,chloritization and carbonation.According to the geological characteristics of the deposit and the ore structure and structure,the metallogenic period can be divided into hydrothermal period and epigenic period,The hydrothermal stage is divided into three metallogenic stages:quartz-pyrite,quartz-sulfide and quartz-carbonate.The element geochemical data of the host rock and ore samples of Caiyuanzi gold deposit show that the rock samples are from the same magma source area,and the ore-forming materials are from metamorphic strata.H-O isotopic study shows that the ore-forming fluid of Caiyuanzi gold deposit is mainly meteoric water mixed with magmatic hydrothermal fluid;S,Pb isotopic study shows that sulfur mainly comes from marine carbonate and lead mainly comes from upper crust.The study of fluid inclusions shows that there are mainly gas-liquid two-phase water inclusions in quartz.The homogenization temperature of ore-forming fluid is between 160?-280?,the salinity changes with 2.55-16.24wt%Na Cl,and the density changes with0.82-1.01g/cm~3.The whole ore-forming fluid belongs to the medium low temperature and low salinity fluid system.Gold mainly migrates in the form of thiocyanate complex in the fluid,and fluid boiling in the open space is the main reason for mineral precipitation.In this paper,the caiyuanzi gold deposit is analyzed and studied in many aspects,The geological and chemical characteristics of the deposit were summarized to determine the genesis of the deposit in caiyuanzi gold deposit,It is preliminarily believed that the genetic type of caiyuanzi gold deposit is Structural altered rock type gold deposit.