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在大地构造位置上,越南西北部地区是古特提斯造山带东段重要的组成部分,并记录了印支陆块和华南板块碰撞拼合历史.其构造归属是厘定该地区古特提斯板块缝合带位置的关键.报道了出露的基底岩石Sinh Quyen岩组副片麻岩的碎屑锆石年龄,探讨其沉积物源和归属问题.该岩组主要由长英质副片麻岩和混合岩等岩石类型构成,被认为是越南西北部中元古代-古元古代基底岩石.采用LA-ICP-MS锆石U-Pb定年方法分析了3个长英质副片麻岩样品的116粒碎屑锆石.123个分析点锆石年龄的统计结果显示,碎屑锆石形成时代主要集中在约1.8Ga左右,有少量约2.2～3.0Ga中太古代碎屑锆石,暗示SinhQuyen副片麻岩沉积物源主要为早古元古代基底岩石.基底岩石在形成时间上与华南板块古老基底相似,推断SinhQuyen岩组在构造归属上可能来自华南板块.部分碎屑锆石边部记录约250Ma变质增生作用,可能与华南板块-印支板块的印支期拼合有关,记录了古特提斯造山作用.
In the tectonic setting, the northwestern part of Vietnam is an important part of the eastern section of the Ghat Tethys orogenic belt and records the history of collision and combination between the Indo-China block and the South China Plate.The structure is attributed to the determination of the ancient Tethyan plate in the area The key to the suture location is the report of the detrital zircon age of the paragneiss from the Sinh Quyen group of exposed basement rocks, Mixed rock and other rock types and is considered to be the Mesoproterozoic-Paleoproterozoic basement rock in northwestern Vietnam.The LA-ICP-MS zircon U-Pb zircon dating of 116 samples The results of zircon ages at 123 analysis points show that the age of detrital zircons mainly concentrates at around 1.8Ga with a small amount of Archean detrital zircons of about 2.2-3.0Ga, suggesting that SinhQuyen deputy The main source of gneisses is the Paleoproterozoic basement rocks, which are similar to the ancient basement of South China Plate in terms of forming time. It is inferred that SinhQuyen Formation may belong to the South China Plate from the tectonism. 250Ma metamorphosis, Able and South China plate - split about Indosinian Indo sector recorded Paleotethyan orogeny.