Discussion On Geological Characteristics And Deposit Genesis Of Xuetangkeng Molybdenum-polymetallic Deposit In Longyan City Fujian Province

The Xuetangkeng molybdenum ore district is located in the southeast of the Yong—Mei upper Paleozoic Platform depression. In the east, it is adjacent to Zhenghe—Dapu geofracture. The ore district is located in the inside and outside contact strips of Dayang granite body. The ore-forming material source and the deposit genesis had been discussed through analysis of petrochemistry, trace element, rare-earth element and geophysical exploration and geochemical exploration, the combination of geological setting of Xuetangkeng.The research showed that the main mineralized sources of molybdenum Xuetangkeng deposit are from the Dayang granite body. The skarn body of molybdenum is formed in the contact position between granite body and wall rock. While the molybdenum-polymetallic ore bodies which are located in well rock have the intermediate-high temperature hydrothermal minerogenetic characteristic. The genetic type of this deposit is the skarnintermediate—high temperature hydorthermal filling-metasomatic compound type ore deposit.By researching on geological characteristics of Xuetangkeng molybdenum deposit, it considered that the distribution of molybdenum ore body are mainly controlled by the fault, fault F₁,F₂ both are bearing fault and storaging fault. The main ore-controlling factors are the fault structure and the magmatic rock.Based on the contrast to the rare-earth element of granite body and skarns body had foud that the rare-earth element of granite body has a characteristic of high content, after analysis thought its high rare-earth content mainly been related with concealed skarns body, and extrapolatesd that there are concealed skarns body. It is first proposed that the high rare-earth content of graniate can be used as a means for forecasting concealed skarn body.