| Huajiaoping Cu-Mo polymetallic mine area is located in the intersection site ofthe three that the Yanyuan-Lijiang Mesozoic depression in western margin of theYangtze Block, the southern section of Yidun arc belt and the Ganzi-Litang suturezone. The main outcropping strata in mine area is Emeishan Basalt Group(P3e) ofPermian, under section(T2b1) and middle section (T2b2) of Beiya Group in MiddleTriassic. The main lithology are microcrystalline basalt, almond-shaped basalt inPermian Emeishan Basalt Group(P3e)); oolitic limestone, microcrystalline limestone,micritic limestone, marble of limestone and bioclastic limestone in under section ofBeiyagroup(T2b1) in Middle Triassic; dolomitic limestone, dolomite in middle sectionof Beiya group(T2b2). The outcropping magmatic rocks in Mine area are diabaseprophyrite of Late Triassic and granite in Yanshan period.Limestone with granite and marble mining is of the main ore build in mine area.Ore body is significantly controlled by tectonic. The ore bodies produced in contactzone of limestone，irregular shape, skarning limestone and basalt in the form oflenticular and vein, it also produced in granite with the form of lenticular, themineralization is characterized by stringer–disseminated ore body.The Ore minerals of Cu-Mo deposit in Huajiaoping mainly include chalcopyrite,molybdenite, diopside,galena, sphalerite, etc. Gangue minerals are mainly pyrite,garnet, actinolite, chlorite, epidote, calcite, quartz, etc. The main structure of the oreare worse shaped and medium-fine structure, hypidiomorphic structure, accountstructure, trim structure, broken structure etc. The main build of the ore is massivestructure, string-stockwerke structures, scattered disseminated structure, brecciatedstructure and so on. Molybdenite Re-Os isotope model age was (85±2)Ma, whichreflect its Metallogenic epoch was in late Yanshan.Rock alteration developmed, such as garnet-actinolite-diopside skarn,silicification, carbonate, chlorite, epidote and petrochemical, all associated with mineralization.Mineralization periods of Huajia Ping Cu-Mo deposit is mainly divided intothree metallogenic and five mineralization stages,followed by contact metamorphismperiod,gas-water hydrothermal period(Skarn stage,Retrograde alteration stage,Sulfidestage),Supergene period.Through systematic study of magmatic rocks, stratigraphy, structure, etc, itshowed that the deposit obviously controlled by rock, lithology and anticline, fracture,fractured structure.The developed structure in mine area provides favorable operating and storagespace for mineralization. anticlinal core is Emeishan Basalt Group while Beiya groupform the legs. The main faults in miner area are Chubo-Xundong fault(F1) whichconnected with Yidun arc and Yangtze block, the Laba-Annan fault(F2) located inbetween the Emeishan Basalt Group and Beiya group in Middle Triassic; Secondaryfaults are F3、F4as parallel to Laba-Tongchanggou fault, and F5、F6which across the F1;The third order fault are the ones that formed by formation and rock mass crushing.The area with developed mineralization and ore circle out of ore body are bothaccompanied by certain parts of faults.Ore body show with the form of lenticular andveins, etc.The magmatic rocks exposed in the mining area can be divided into two types ofvolcanic and intrusive rocks.Volcanic is Permian Emeishan basalt,intrusive rocks areYanshan granite which mainly exposed in the interchange of main fracture F1andsecondary fracture, F5, F6in mine area.Yanshanian granite is the main source ofore-forming elements and fluid for the deposit, the geochemical characteristics ofwhich is similar to that of porphyry-skarn copper polymetallic ore in Redhill, whoseSiO2content is between66.59%~68.93%,TiO20.55%~0.60%,Al2O314.15%~15.15%，MgO1.19%~1.39%,it has lower MgO compared with other granite,Na2O3.20%~4.17%,K2O2.94%~5.91%;Na2O+K2O7.11%~9.11%,Overall, the content ofK2O is more than Na2O, which means it is a series of high K calc-alkaline granite,with the main pattern of A; A/CNK value of about0.882~1.027, means the granitebelongs to metaluminous and peraluminous;Total ΣREE168.42~233.847,The ratio ofthe LREE and HREE is13.56~16.94,(La/Yb)N25.97~36.56, ratio of (La/Yb)Nishigh, which is conducive to the formation of Cu-Mo deposit.REEChondrite-normalized curves of granite in miner area shows a right-wing style,diagram shows it is of rich LREE, value of δEu is about1.0, the maximum is1.01, allnot reflect obvious abnormality, indicating that the exchange of material has occurring during granitic magma intrusioned the mafic Emeishan basalt, therefore the granitehas characteristic of the Emeishan basalt.Surrounding rock is impure limestone at the under section of Beiya group(T2b1)in Middle Triassic. In which thickness variation is large, and joint develops. Affectedby magma intrusion the contact zone gets alteration of marble, skarn apparently,which controls the type and mineralization characteristics of skarn.Geochemical studies in the area indicate that it has significant abnormality of Cu,Mo polymetallic ore,distributing along the north-north-east with irregular oval.Thereare two high anomalous area, southern abnomal area has the distribution of near thenorth-south, and main elements are Cu, W, Mo; abnormal area in north along theLaba-Zhangjia volcanic faults distributes in the pattern of strip from east to west,mainly has Cu anomaly.Geophysical studies in the area showed that there has obviousmagnetic anomaly in Logi-Annan and Logie-Dongba, which are importantprospecting areas.Previous studies indicate that mineralization age of Huajiaopingcopper-molybdenum deposit is similar to that of granite discovered in same area, thatis Yanshan period, indicating Huajiaoping area existed collision in Yanshanianorogeny.Borehole data and laboratory analysis show that the ore body (KT11)produced in the Yanshan granite, is concealed whole rock mineralization.Therearegranite outcrops in southeast of miner area.combining with its geochemicalcharacteristics it speculates there is a certain scale of concealed rock deep in the area,and the rock has close relationship with mineralization.Field geologic investigation and laboratory studies have found there must bestructural faults when mineralized bodies exists, ore (KT1) produced in limestone ofunder section of Beiya group and fracture zone of Emeishan basalt. Microscope studyin polished thin section finds that many of the mineralization alters along fractures.The fractures in north-west as well as part of east-west in miner area are importantprospecting positions.Geological survey found in this area there are a lot of mined holes, indicatingpredecessors have done related geological work here, they are important prospectingindicators; In addition, the mineralized often accompanied with surrounding rockalteration in different degrees, so surrounding rock alteration is one of the signs ofprospecting.Through analysis to metallogenic geological conditions in HuaJiaoPing Cu-Modeposit, combining with regional geophysical and geochemical anomalies, and studies on mineralized information at the mine area, three regional metallogenic prospect aredetermined in the periphera of Huajiaoping, there are Jiulong area, Annan area andDongba area, and Jiulong are the area of Class A prospects.Jiulong prospective area locates from thethe west of HuaJiaoping mine to Jiulong,its east is along Laba-Zhangjia volcanofault. It mainly is the Cu polymetallic orearea;Annan prospects locates from southwest of HuaJiaoping mine toAnnan.Geological survey in the area finds Cu-Au mineralization, geochemicalanomalies, mainly Cu-Au polymetallic ore area;Dongba prospects locates in theeastsouth of Huajiaoping ore area is the most likely prospects. In the district, watersystem, soil geochemical has obvious anomalies. Geological survey finds many pointsof mineralization and well developed structure, indicating it is the Cu-Pb-ZnPolymetallic mine area. |
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