Study On Geological Characteristics And Genesis Of Cuyu Gold Deposit, Panshi City, Jilin Province

Cuyu gold deposit, located in Panshi City, Jilin Province, tectonically, the east ofthe Pacific plate, the north of the Siberian plate, tectonic positions in the the eastern ofTianshan-Xingmeng orogenic belt. This region is an important Au and nonferrousmetal metallogenic zone in northeast China, and has ascendance on regionalmetallogenetic condition.The strata exposed in the mine area is sample, mainly the Mopanshan group. Thefaults structures are relatively developed. The faults can be divided into three groups,respectively to NW, NE, SN. Deposits are strictly controlled by the NW-trending faultstructure, the mechanical properties,occurrence and scale of the fault structure controlthe morphology, occurrence and size of the ore body, as well as sub-enrichmentpatterns. Regional magmatic activity is relatively frequent and magmatic rocks arewidely distributed in Cuyu area, mainly Hercynian magmatic rocks.Seven ore bodies are found in the mine, numbered X1to X7. Also somemineralized bodies. Ore type is quartz vein type. Ore minerals are pyrite, chalcopyrite,pyrrhotite, sphalerite and native gold. Ore textures contains anhedral granular textures,euhedral-hypidiomorphic textures, crushing textures. Ore structure contains veinletstructure and disseminated structure. alteration consist of silicification, carbonation,sericition and chlorition. The mineralization period can be divided into four phases:pyrite-quartz mineralization stage,quartz-pyrite mineralization stage, quartzpolymetallic sulphide mineralization stage, carbonate formation stage.Cuyu glod deposit is mainly distributed in the Hersynian granit.The granit isbelonging to calc-alkaline. The trace elements of diorite show enrichment in LILE(such as K、Rb、Sr), more mobile incompatible elements(such as Th, U) andLREE, relative depletment of HFSE(such as Nb, Ta, Ti, P) and HREE, and showobviously negative Eu anomalies. LA-ICP-MS U-Pb zircon data of the diorite giveweighted average ages of253.76±1.53Ma and concordant age of253.51±1.61Ma,which are in the late Permian period.The results show that fluid inclusions in quartz crystals can be classified intoaqueous two-phase and CO2-bearing three-phase inclusions. Salinities of aqueoustwo-phase inclusions content of NaCl range from1.73%to11.23%,densities rangefrom0.71to0.88g/cm3, and homogenization temperatures range from233.1℃to304.4℃. Salinities of CO2-bearing three-phase inclusions content of NaCl range from7.64%to10.87%, densities range from0.54to0.92g/cm3, and homogenizationtemperatures range from268.9℃to340.4℃. Laser Raman spectroscopy ofinclusions indicate that the principal gas-phase components are H2O and CO2.Thestable isotope analyzing results show that the metallogenic fluid is originated from themagmatic hydrotherm after the differentiation of mantle-derived C-H-Ofluid.According to the diagram of isochore, the ore-forming pressure can becalculated to almost95to135MPa, the ore-forming depth ranges from8.02to9.69km.Study on the genesis of the Cuyu Gold Mine, mineralization time should beYanshanian tectonic regime from compression to extension in conversion period.Cuyu gold mine in the genesis have a similar basic characteristics with orogenic golddeposit. Tectonic setting is continental arc orogenic environment. The genetic type ismesozonal orogenic gold deposit.