关键词: 变镁铁质岩, 热液锆石, UPb年龄, 变形时代, 泛非构造热事件, 桂北地区

Abstract:  The chronology of  Shanglang metamafic rocks in Longsheng area of northern Guangxi was researched by LAICPMS zircon UPb dating. The age information of two chronological samples  are nearly consistent, concentrated in eight intervals (114.8±1.6), (152.0±5.0), (213.9±3.5), (274.6±9.4), (442.5±6.7), (553.5±9.2), (774.2±5.9), and (822.0±10.0) Ma. The genetic types of zircons show that the zircon of (774.2±5.9) Ma is the youngest magmatic zircon, representing the emplacement age of  Shanglang metamafic rocks. The zircon of (822.0±10.0) Ma is the captured zircon, representing the age of the captured materials during the magma emplacement. The hydrothermal zircon ages are (114.8±1.6), (152.0±5.0), (213.9±3.5), (274.6±9.4), (442.5±6.7), and (553.5±9.2) Ma, representing the time limits of the later tectonic thermal events of metamafic rocks. Among the hydrothermal zircon ages, (442.5±6.7) Ma represents the ductile deformation age of ShouchengSanmen fault, which is consistent with the ductile deformation age of regional NNE faults, and the hydrothermal zircon age of less than (442.5±6.7) Ma is the tectonic thermal events after ductile deformation. The existence of (553.5±9.2) Ma PanAfrican hydrothermal zircon indicates that the South China continent was influenced by PanAfrican tectonic thermal events and should be  related to Gondwana continent. 

Key words: metamafic rocks, hydrothermal zircon, UPb age, deformation era, PanAfrican tectonic thermal event, northern Guangxi