特提斯喜马拉雅早白垩世早期基性岩墙研究及其对东冈瓦纳大陆裂解的指示

理解东冈瓦纳大陆的裂解时限和方式对于重塑印度大陆北缘几何形态及古地理格局、探讨印度-欧亚大陆汇聚过程至关重要，目前尚存争议。基于研究地点和研究方法的不同，获得的东冈瓦纳大陆的初始裂解时限差异很大：从晚侏罗世到早白垩世。而基性岩墙活动时限短，构造意义明确，是古大陆重建的关键指标。因此，特提斯喜马拉雅早白垩世的基性岩墙为限定东冈瓦纳大陆裂解提供了很好的研究载体。本项目拟以特提斯喜马拉雅东段（措那-哲古-琼结地区）早白垩世早期基性-超基性岩墙为研究对象，在详细的野外观测、岩石学、矿物学研究的基础上，通过高精度的副矿物U-Pb年代学厘定其时空分布格架。进而基于单矿物成分分析反演成岩时的温压条件，结合全岩主-微量元素特征和Sr-Nd-Hf-Os同位素联合示踪，查明特提斯喜马拉雅早白垩世早期基性岩浆的岩浆源区及贡献量，约束其形成的地球动力学背景，为理解东冈瓦纳大陆裂解历史提供更多证据。

The separation of the Indian Plate from the Australia–Antarctic Plate is the key to understand paleogeographic reconstruction of Eastern Gondwana, which still remain a topic of debate. Due to different methods applied at different locations, the timing of initial breakup remains in great dispute, ranging from Late Jurassic to Early Cretaceous. The mafic dykes represent initial or incipient rifting and the earliest Early Cretaceous mafic dyke swarm in Tethyan Himalaya provide an important opportunity for constraining the breakup history of the Eastern Gondwana. This project will focus on the mafic dykes exposed in Cona, Zhegu and Qiongjie areas. Detailed field observations, petrological and mineralogical studies will be performed to constrain their spatial and temporal distributions. Combined with whole-rock geochemical analysis and in-situ element and isotopic analysis (Sr-Nd-Hf-Os), the origin and petrogensis of these mafic dykes will be revealed. All these studies will contribute to understanding the breakup history of Eastern Gondwana.