非洲东北部Nubia泛非构造带的性质及时代研究

Late Neoproterozoic Pan-African tectonic belt formed by the closure of the Mozambique Ocean during the transitional stage from break-up of the Rodinia super-continent to amalgamation of the Pangea super-continents, along which the Western Gondwana blocks amalgamated with the Eastern Gondwana blocks. Thus, the Pan-Africa tectonics become a hot issue in academic research due to its tectonic implications. Although many progresses have been achieved during the past decades, the nature, the temporal and spatial distribution of the Pan-Africa orogeny and tectonic movement are still controversial. . This project will focus on the properties and tectonic evolution of the Nubian Pan-African tectonic belt (between the Western Egypt - Northeastern Sudan and Red Sea). Based on detailed field investigations, the litho-tectonic assemblage of the ophiolitic mélange will be established in detail. According to detailed investigation of elemental and isotopic geochemistry of the ophiolite, island-arc volcanic and magmatic rocks, the petrogenesis, properties and tectonic setting of the ophiolite and related rocks, as well as the Nubian Pan-African tectonic belt, will be definitely confirmed. Together with timing of the ophiolite and related rocks by means of high-resolution zircon U-Pb age dating, the tectonic evolutionary history of the Mozambique ocean and the Nubian Pan-African tectonic Belt will be reconstructed. . According to the detailed structural analysis along several cross-sections and large-scale mapping, the geometry, kinematics and dynamics of the deformation will be determined, which will be useful indicators for the polarity of oceanic subduction. 40Ar/39Ar dating on amphibole, muscovite and biotite will be used to constrain the age of deformations.. Taken into together all above field investigation, petrology and geochemistry of the ophiolites, island-arc volcanic and magmatic rocks, as well as the geochronology of different tectonic units and deformations, the mechanism of the closure of the Mozambique, amalgamation of the Western Gondwana and the Eastern Gondwana blocks will be identified. The properties of the Pan-Africa orogeny and tectonic movement, the temporal and spatial tectonic framework of the Nubian Pan-Africa orogeny can be constrained accordingly.

新元古代末期的泛非运动发生于Rodinia超大陆裂解、Pangea超大陆聚合的转换时期，由于莫桑比克洋关闭，导致东岗瓦纳和西岗瓦纳沿东非-南极造山带拼接形成统一的Gondwana大陆，并因此成为地学界研究的热点。但是，泛非造山带构造演化时空格局及性质长期存在争议。本项目重点开展非洲东北部Nubia泛非构造带（埃及-苏丹东北部、红海以西）中残存的蛇绿岩、岛弧火山岩以及相关岩浆事件的岩石成因、构造变形以及同位素年代学研究 。通过野外地质、构造变形解析、岩石学综合研究，查明Nubia构造带现今构造样式，筛分不同期次构造变形的叠加改造特规律，进行构造的分期配套，确定不同构造的运动学和动力学特征。在此基础上，运用多种同位素年代学手段，确定不同构造形成演化时间格架；深入开展蛇绿岩及相关构造岩浆活动的地球化学、同位素年代学研究，确定莫桑比克洋闭合方式、Nubia泛非造山带的性质、时空格架及其演化过程。

新元古代末期的泛非运动发生于Rodinia超大陆裂解、Pangea超大陆聚合的转换时期，由于莫桑比克洋关闭，导致东岗瓦纳和西岗瓦纳沿东非-南极造山带拼接形成统一的Gondwana大陆，并因此成为地学界研究的热点。但是，泛非造山带构造演化时空格局及性质长期存在争议。本项目重点开展非洲东北部Nubia泛非构造带（埃及-苏丹东北部、红海以西）中残存的蛇绿岩、岛弧火山岩以及相关岩浆事件的岩石成因、构造变形以及同位素年代学研究。通过四年的研究工作，取得了如下进展：（1）开展了Nubia构造带之埃及东部沙漠地区的泛非蛇绿混杂带岩石构造组合的野外地质调查与厘定。（2）完成了大量的同位素年代学和地球化学样品测定，为未来继续深入研究泛非运动和Nubia构造带形成演化奠定了基础。（3）深入研究了泛非Nubia构造带蛇绿岩及相关岩石组合的同位素年代学和地球化学特征，探讨了其成因机制与演化过程。（4）依托本项目，与埃及Tanta大学开展了深入合作，不仅取得了新的科研成果，而且在人才合作人才培养方面取得了重要进展，联合培养硕士2名、博士研究生1名。