Study on metallogenetic mechanism of Xiangshan uranium ore-field

This paper puts emphasis on the study of metallogenetic ages and environment,anatomizes the vertical variation regularities of matter composition at representative deposits.The results indicate that there are two uranium mineralization phases in Xiangshan uranium ore field,The first phase of mineralization (uranium haematite) took place at 115±0 6 Ma associated with the volcanic collapse and the intrusion of subvolcanic magma.The second phase of mineralization (uranium fluorite hydromica) occurred at 99±6 Ma and was related to the regional extension and intrusion of intermediate basic dikes caused by the relax of the Pacific Plate subduction.In Xiangshan ore field,there is a horizontal alteration trend with alkaline alteration in the eastern part and acidic alteration in the western part,meanwhile a vertical alteration trend with alkaline alteration at depth and acidic alteration at shallower level.Based on the discussion of metallogenetic mechanism in Xiangshan uranium ore field,it is suggested that the mineralization of the Xiangshan uranium ore field resulted from the combination of multiple stage uranium enrichment,superimposition of multiple stage hydrothermal alterations and many other geological factors.