Crustal evolution of the Shiwandashan area in South China:Zircon U-Pb-Hf isotopic records from granulite enclaves in Indo-Sinian granites

标明日期的 U-Pb 在东南的 Guangxi 省从 Shiwandashan 区域在 Jiuzhou peraluminous 花岗石从 metasedimentary granulite 被外国领地包围的土地在锆石上结合了 Hf 同位素分析，华南在这份报纸被介绍。结果证明这些 granulite 被外国领地包围的土地的 protoliths 主要由有一座山峰的碎屑状的材料在 822 妈变老的 Neo-Mesoproterozoic (5641061 妈) 组成。这些材料可能从在 Rodinian Supercontinent 的 Neoproterozoic 决裂期间是 emplaced 的火的岩石被导出。辅助沉积包括 Paleoproterozoic (17782227 妈) ，有最旧的 U-Pb 的甚至 Meso-Paleoarchean 材料在 3551

U-Pb dating coupled with Hf isotope analyses on zircon from metasedimentary granulite enclaves in the Jiuzhou peraluminous granite from the Shiwandashan area in southeastern Guangxi Province, South China are presented in this paper. The results show that the protoliths of these granulite enclaves were mainly composed of Neo-Mesoproterozoic （564-1061 Ma） clastic materials with a peak age at -822 Ma. These materials were probably derived from the igneous rocks that were emplaced during the Neo- proterozoic breakup of Rodinian Supercontinent. Subordinate sediments include the Paleoproterozoic （1778-2227 Ma） and even the Meso-Paleoarchean materials with the oldest U-Pb age at 3551±8 Ma, indicating the existence of ancient crustal rocks in the area and/or its surrounding regions. Younger grains include the early Mesozoic （234±2 Ma） magmatic zircon populations and the late Permian （253±3 Ma） metamorphic zircon populations. Further zircon Hf isotope analyses reveal that their protoliths were complex, containing both recycled crustal rocks and juvenile materials. Combined zircon U-Pb ages and Hf isotope compositions indicate that at -253 Ma, the Shiwandashan area experienced an intensive thermal event that resulted in the granulite-facies metamorphism; and that crustal remelting occurred at -234 Ma to form the S-type granitoids during the uplifting stage. The metasedimentary granulite enclaves are resitites of these granitoids.