缅甸甘宝锡钨矿区花岗岩年代学、岩石成因及其地质意义OA北大核心CSTPCD

The Late Cretaceous to Paleogene granite belt,closely associated with the formation of the Southeast Asian tin belt,is extensively developed in the Myanmar region.However,there is still no unified understanding of the dynamic background and spatiotemporal patterns of granite formation.This study presents a comprehensive investigation of the granite in the Kanbauk mining area of Myanmar through zircon U-Pb dating,petrology,and geochemistry.The research reveals that the Kanbauk granite is predominantly composed of biotite monzogranite,with zircon LA-ICP-MS U-Pb ages of(64.0±0.69)Ma(n=25,MSWD=1.9)and(65.7±1.5)Ma(n=19,MSWD=3.8)for two samples,indicating magmatic emplacement during the Late Cretaceous to early Paleogene.Representative rock samples exhibit high SiO2(74.5%-77.2%)and negative εNd(t)values(-7.51 to-6.95)with TDM2 ages(1.55-1.51 Ga)suggest that the magma's initial melt originated from partial melting of the Middle Jurassic continental crust and underwent significant fractional crystallization.The granite bodies in the mining area are part of the Late Cretaceous to Paleogene granite belt(90-60 Ma)in Myanmar,and they formed in an arc-trench extensional setting induced by plate subduction.The granite from the Kanbauk mining area,along with tungsten mineralization,represents specific manifestations of magmatic-metamorphic-mineralization events during the eastward subduction of the Neo-Tethyan oceanic crust.