Geochronology, Geochemistry, Petrogenesis And The Assessing Of The Prospecting Potential For Uranium Deposit Of The Pucheng Composite Body In The Northwest Fujian Province

The biotite alkali feldspar granite and the biotite adamellite of Pucheng Composite Body, which are located in the north-west of Fujian Province, have been studied for LA-ICP-MS zircon U-Pb ages and whole-rock elemental and Sr-Nd isotopic compositions to constrain their sources and tectonic settings. This study also assesses the prospecting potential for uranium deposit of the plutons.The biotite alkali feldspar granites crystallization ages are159.8±2.3Ma129.8±1.3Ma、129.4±1.7Ma and110±1Ma, indicated that they were formed by the Yanshanian magmatism events. The biotite adamellite crystallization age is106±1Ma,also generated in late Yanshanian stage.Comprehensive mineralogical,geochemical features and Sr-Nd isotopic composition suggest that the160Ma and130Ma samples are highly fractionated A-type granites,the biotite alkali feldspar granites of110Ma have the geochemical characteristics as fractionated I-type granites,the106Ma samples are A-type granites. At the same time that the rock is a product of partial melting of the crust-mantle mixing of different source rocks occur at different times, and experienced varying degrees of differentiation and evolution of the role.With the integrated analysis of the type of this rock, we consider that it was in a extensional environment during Late Jurassic to Early Cretaceous. The preliminary view that the biotite alkali feldspar granites of160Ma might be related to the deep-fault slip resulted from the low-velocity oblique subduction of the Pacific plate, or the lithospheric extension which is irrelevant to the subduction of the Pacific plate.The130Ma and110Ma samples be related to the Pacific plate subduction caused back-arc extensional background environment.According to the research results of Indosinian granites and uranium mineralization in South China, consolidated rock geological-geochemical characteristics of preliminary analysis to determine the rock mass production of uranium capacity is limited.