越南西北部Phan Si Pan杂岩带Suoi Chieng组和Sinh Quyen组物源特征及其构造意义

越南西北部地区位于印支板块和华南板块的结合处，记录了印支板块和华南板块碰撞拼合历史，越南西北部地区基底的构造亲缘性问题涉及东南亚大地构造单元的划分。以往对越南西北部地区前寒武纪研究主要来自岩浆岩记录，而对区内广泛分布的前寒武纪浅变质沉积岩系的沉积时代和物质来源缺乏系统可信的同位素年代学约束和相应的岩相学证据。本项目拟选择越北地区Phan Si Pan杂岩带为研究对象，聚焦于杂岩带内的古元古代到中元古代Xuan Dai群中的Suoi Chieng组和Sinh Quyen组沉积地层时代和沉积岩物源示踪，拟综合运用沉积地质学、砂岩成分、火山灰夹层锆石高精度SHRIMP U-Pb定年、砂岩碎屑锆石LA-ICP-MS U-Pb年龄谱和Hf同位素等方法，揭示它们的物源特征，为研究区前寒武构造演化、构造亲缘性以及印支、华南板块边界提供重要的依据。

North Vietnam located at the tectonic junction zone between South China and Indochina block, forms an important part of the expansive Tethyan tectonic-metallogenic domain and preserve the history of collision of South China and Indochina block. The tectonic affinity of North Vietnam relate to demarcation of SE Asia geotectonic units. Previous studies have mainly focused on the geochronological evidence from Precambrian igneous and metamorphic rocks in the region, whereas little attention was paid to the Precambrian sedimentary sequences. Paleoproterozoic to Mesoproterozoic metasedimentary rocks are widespread in North Vietnam, but their accurate depositional ages and provenance are poorly constrained. This proposal focuses on selected Paleoproterozoic to Mesoproterozoic metasedimentary in north Vietnam, aiming to provide high quality chronologic framework of the Paleoproterozoic to Mesoproterozoic metasedimentary rocks in North Vietnam. A comprehensive study of sandstone petrology, detrital zircon U-Pb dating and Hf isotope analysis will be carried out in order to track the provenance of Paleoproterozoic to Mesoproterozoic metasedimentary rocks and their accurate depositional ages. Geochronology work will be based on field investigation and systematic sampling along representative geological traverses and corridors. This proposal will provide new constraints on the Precambrian evolution, tectonic affinity of North Vietnam and the boundary of South China and Indochina block. Furthermore, incorporating the inferences from published data from contemporaneous sedimentary of different Precambrian blocks in the world, this proposal will offer further refinement on provenance variation related to the role of north Vietnam in Columbia supercontinent.