Petrology Characteristics Study And Metallogenic Prediction Of Cu, Mo Ore Deposits In Buried Porphyry Of Wushan Rocks Of Jiangxi Province

Wushan copper deposit, the compositional part of Latter Yangtze Cu-S-Fe metallogenic belt of circumpacific metal metallogenic belt, is situated at the southern margin of Yangtze fault belt in the central geosynclines of Latter Yangtze area in Yangtze paraplatform, and is controlled by Yangtze fault belt and northwest and northeast fault belt in metallogenic processes, which belongs to the same metallogenic belt as Chengmenshan porphyry-copper-deposit in space and contains advantageous mineralogenetic geological conditions and abundant mineral deposits.The north metallogenic belt and the south metallogenic belt are divided in Wushan copper deposit. The former belongs to bedding-controlled sulfide deposit, while the latter is classified to skarn-type deposit and porphyry-copper-deposit, which three different ore body and mineralized complex have relationship in space, similarity in forming-age and "strain" contacts in metallogenic genesis, whose ore-forming fluid derives from deep crust and squeezes into various metallogenic country rock medium by kinds of method, through which metallogenic mode the "three-in-one" deposit formed.The comprehensive studies both indoor and wild-field comply to the working sequence of identifying wild-field anomaly, concluding regional metallogenic laws, correlation analyzing of typical ore deposits, parsing of key ore deposits (spots), in which the porphyry and the ore-bearing rate of the south Wushan metallogenic belt are analyzed specially by systematic studying of mineralogy, petrology, ore deposit geochemistry, isotopic geochemistry, and the ore-bearing sites of the porphyry are outlined, which identify the ore-bearing characteristic of the porphyry in the deposit, and the following main cognitions are acquired.1. Wushan porphyry rock body exposes as a occurrence of ultra-hypabyssal rock and contains porphyry quartz-granodiorite, quartz-ivernite, porphyry granodiorite in majority and granitic aplite and diorite in minority, which minerals are quartz, plagioclase feldspar, potassium feldspar, hornblende and biotite, et al.2. The main rock type of Wushan porphyry rock body is calc-alkaline type, which geochemical show REE characteristics of similarity to I-type granite of active continental margin, and the geochemical indexes of which are alike to syn-melting granite which indicates that the geotectonic setting of diagenesis of the rock may be IAG, CAG, CCG, and belongs to the arc-volcanic granitoid of high maturity.3. Middle-acid porphyry rocks of Wushan porphyry copper deposit have high relationship with mineralized intensity, which expressed in that the ore-bearing rate of the porphyry rocks is controlled by litho strongly, for that porphyry quartz-granodiorite and porphyry granodiorite are the main ore-bearing rocks and have stronger potential of forming the porphyry copper deposit than sub-aluminous granite of alkaline in enrichment.4. After elements correlation analysis, it is predicated that the plutonic Cu deposits and Mo deposits distributed in different parts of lithofacies, which may be a new ore body.5. Wushan porphyry-copper-deposit belt is situated in the upper position of the porphyry rocks, contacting with inner skarn copper-deposit and consist a entire body. The deeper part of the porphyry-rock distributed the porphyry-Mo-deposit belt(-410—560m) and exists somehow reservoir of deposits from the ranging inclination of ore body.