SHRIMP zircon U-Pb geochronology of Indosinian granites in Hunan Province and its petrogenetic implications

摘要: The SHRIMP zircon U-Pb geochronology of three typically Indosinian granitic plutons with peraluminous and potassium-rich affinities (Tangshi ultraunit for Weishan Baimashan, Longtan Guandimiao) is presented in Hunan Province, South China. analyses zircons from biotite monozonite granites Weishan, Baimashan Guandimiao show the single tight clusters on concordia, yield weighted mean 206Pb/238U ages 244 ± 4, 243 3 239 Ma, respectively, representing crystallized these granites. These data suggest that as previously thought formed at a narrow age span. In combination other data, it inferred within China Block probably distributed Hunan, Jiangxi, Guangxi Guangdong provinces planar shape, were derivation crustal materials intracontinental thickening setting. precisely geochronological provide important constraints better understanding spatiotemporal pattern early Mesozoic tectonic evolution Block.