Study On The Geological Characteristics And Enrichment Regularities Of Mineralization Of Kaerqueka Copper Deposit, Geermu City,Qinghai Province

Kaerqueka copper deposit is located in Wutumeiren town,Geermu city of Qinghaiprovince, belonging to the west of Eastern Kunlun orogenic belt.There develops a series ofmetal deposits.In this paper,we mainly have a study on the two ore blocks:A(Yelasai) andB(Suolajier).The main strata exposed is Tanjianshan group.The intrusion,which major lithology isporphyraceous biotite monzonitic granite and biotite granodiorite,distribute in a large aera.Petrography,chronology and petrogeochemistry study shows that: the porphyraceousbiotite monzonitic granite formed in the early Carboniferous and rock mass formed in thesyn-collisional background when the ancient tethys ocean had been closed and had enteredthe stage of intracontinental orogeny; the biotite granodiorite formed in the middleTriassic and the tectonic background of the rock mass formation is subductionenvironment. Faults developed in this area.There are two main groups of faults, theNWW faults and the NE faults.The NWW faults group is the backbone in the area and thepolymetallic ore bodies occur mainly in the group and its secondary faults.Totally3alteration zones are circled in the ore block A.They are all come fromporphyraceous biotite monzonitic granite rock mass.The alteration zones are made up byfradmentized porphyraceous biotite monzonitic granite, later aplite granite and quartz vein.The general strike of the alteration zones is NW-SE and the trend is NE.The dip angleis between65°to80°.Ore type is given priority to fracture zone altered rock type andquartz vein type is also developed.Alteration types of wall rock are kaolin, sericitization,potassium, silicification and chloritization, etc.4skarn zones (including surface3, deep1)are circled in the ore block B.They are all come from the contact area of granodiorite,porphyraceous biotite monzonitic granite and the Tanjianshan group. The general strike ofthe skarn zones is NWW and the dip angle is between20°to85°. Ore types are mainlyincluding tetrahedrite chalcopyrite porphyry copper ore, brass molybdenite, pyrite oreskarn ore and peacock petrochemical (including brass) magnetite ore four types (accordingto the exploration data).In the skarn zone alteration are mainly silicon card lithification,diopside in petrochemical, chloritization, epidotization, silicide, etc.The experimental results show that the metallogenic fluid of the ore block A ofKaerqueka has experienced a evolution that the salinity of metallogenic fluid went fromhigh to low. The peak temperature range of gas-liquid two phase inclusions is260~260℃and the peak temperature range of three-phase inclusions containing CO2is340~340℃.The metallogenic fluid has the characteristics of high temperature.The range ore-formingpressure is51~97mpa and the range of metallogenic depth is5.70~8.12km.Among theore-forming materials, sulfur is given priority to with deep magmatic sulfur source, withthe participation of a small amount of sulfur of surrounding rock, and also may be in theprocess of ore-forming fluid migration from the earth’s crust matter from various genesisof sulfur.Source of metallogenic fluid is mainly magmatic water, post stack with otherfluid such as rainfall.Comprehensive analysis thinks, the genetic type of the ore block A ofKaerqueka is mesothermal-hypothermal hydrotherm vein type copper deposit which iscontrolled by linear faults and the genetic type of the ore block B is the typical skarn typecopper deposits.On the basis of the comprehensive research results, the enrichment regularities ofmineralization of Kaerqueka copper deposit can be summarized that the ore block A isstrictly controlled by the NWW faults.The potential relationship between mineralization and silicide is the most closely and the ore block A has a strict distinction with typicalporphyry copper deposits. The ore bodies of the ore block B is both controlled by theskarn contact zones and the NWW faults and it is most likely to produce rich ore bodieswhen the local layer has a large angle oblique contact with skarn contact zones.