Geochemistry Character Of Gaerqiong Copper-gold Deposit, Geji Country, Tibet

Gaerqiong Copper-gold deposit is located in the west of bangong-nujiang metallogenic belt,which on the south Anglonggangri magmatic arc of Gangdese-lasa plate and on the north qiangtang-sanjiang plate,Which is located locates in the intersection of the Shiquanhe Late-Yanshan Junction Zone and Gangdese Niainqentangula plate. With meso-Tethys evolution, mineral-formation condition very favorable with tectonic movement and magmatic activity. What the deposite diggings are carbonatite and pyroclasticrock which belongs to Duoai Formation of Zelong Group, Cretaceous system. Magmatic rocks for late yanshan period intermediate-acidic intrusive rocks.Constructed to fracture primarily, folding structures not development. The Main orebody in quartz diorite and and carbonate contact take, outputing as bedded vein near-bedded and lensing. Useful elements for copper and gold, silver and molybdenum potential economic value.The deposit consists of pepper and salt structure ore and veinlet disseminated ore,mainly of for chalcopyrite , bornite and free gold.Can be divided into the magmatite dioritoid and granite classes, two types of rocks are enrichment Rb, Ba, Th, U etc large-ion lithophile element, losses Nb ,Ta, Zr, Hf etc high field strength elements; But the granitoids are more losses Sr, Ti elements. Dioritoid have active continental margin of trace, rare earth element characteristic; Granite have collision orogens, trace, rare earth element characteristic. Dioritoid have isotopic element of crust-mantle system, Granite have isotopic element of crust system.According to the elements within its for difference, endoskarn and exoskarn. Endoskarn have more SiO₂, Al₂O₃, K₂O, Na₂O, Copper-molybdenum;With less Eu, light rare-earth element enrichment internal differentiation is more apparent, heavy rare-earth losses and differentiation of rare earth elements is not clear. Exoskarn have more Fe₂O₃, CaO,Copper-gold,With less Eu, light rare earth elements is obvious, heavy losses differentiation is not clear. Isotopic element shows that the skarn carbon and oxygen the main comre from the surrounding rock, the less come from magmatism.Combined with the Gaerqiong poor-copper ore regional geological characteristics, the geological characteristics, geochemistry, think Gaerqiong deposits formed in late yanshan period. Mineralization activities there are two major periods, about 112Ma early for active margin of trace dioritoid intrusive carbonate with formation mainly with copper, gold mineralization; About 87.66 Ma late for the collision environment output granitoids are invading carbonate, early flash in contact dioritoid with form the mineralization mainly molybdenum in early ore-forming materials, and played the role of further enrichment. Mining area surrounding conditions favorable, structure condition and two periods magmatic activity eventually contributed to the formation of Gaerqiong copper-gold deposit.