Henan Province Xixia County Longtan Gold Deposit Forming Material Source And Genesis

Longtangou ore deposit in Xixia County of Henan Provnce is situated in the eastern part of Qinling orogenic belt which is located at matching belt between North China platform and Yangze platform. Its ore-body occurred in the endo-or exdo-contact zone of Heiyanzhen granite body and strata of Erlangping Group Huoshenmiao Formation. Based on the study and analysis on petrochemistry, trace element, rare-earth element, fluid inclusion and previous achievements, the ore-forming material origin and the deposit genesis are discussed.The research believes that Longtangou gold deposit experienced a multistage metallogenesis. The main ore-hosted stratum is Erlangping Group Huoshenmiao Formation. The mineralization can divided into three mineralization stages, the erarly syngenetic depositional stage, the midterm metamorphic enrichment stage, and the late hydrothermal metasomatic stage.Based on the study on strata, structure, magmatic rock and race element, rare-earth element, fluid inclusion, it is suggested that the ore-forming material origin may be closely related with the ore-forming time. Different ore-forming time, strata, structure and magmatic rocks take different function on forming gold deposit. In the early syngentic depostional stage, the ore-forming material of strata begin to initial enrich, in the midterm metamorphic enrichment stage, the ore-forming material of strata are activated and enriched in local, and the late hydrothemal metasomatic stage, the granite body provide ore-forming materials and heat.Studies suggest that the mineralization character in this area is very similar to hydrothermal-replacement deposit. Mineralization temperature belongs to medium-low temperature range; the ore-bodies are veined, they are in the center of low temperature and low pressure, and located next to the contact zone of granite body; It can be drawn that the wall rock is negative circle by the analysis of trace element of wall rock; the cation type is the Ca-Na by analysis of inclusion component. The deposit genesis belongs to the hydorthermal metasomatic deposit.