新元古代汉南毕机沟镁铁质层状杂岩成因及岩浆演化

Studies on Neoproterozoic mafic-ultramafic plutons along the northern margin of the Yangtze Block can provide constrains on mantle-derived magmatism, and their responses to convergence and rifting of the supercontinental Rodinia. However, their tectonic settings and forming mechanism has still been the subject of considerable debate. The Bijigou Fe-Ti-V-bearing layered intrusion in the Hannan area is chosen in this project. Through whole-rock platinum-group elemental, Re-Os isotopic and in-situ mineral geochemical analyses, combined with the crystalline thermodynamic simulation, this project intends to reveal the magma source and its evolution, and to build up a metallogenic model. Furthermore, based on the comprehensive comparison of the characteristics of mafic-ultramafic layered intrusions in different tectonic settings, the project aims to establish the petrogenetic and metallogenic environments for the Bijigou intrusion, which could provide a new scientific perspective for understanding the Neoproterozoic magmatic-tectonic nature in the northern margin of the Yangtze Block, and the reconstruction of its tectonic framework. In addition, building up petrogenetic and metallogenic models of the Bijigou layered intrusion is of great theoretical significance in discussing the diversity of mineralization in the early stage of the northern margin of the Yangtze Block.

扬子板块北缘新元古代镁铁－超镁铁质层状侵入体的研究可为探讨幔源岩浆演化，及其在Rodinia超大陆聚合－裂解演化过程中的作用等热点问题提供制约。然而目前，对这些岩体的构造背景和成岩成矿机制仍存在很大争议。本项目拟以汉南毕机沟镁铁质层状侵入杂岩和相关矿床为对象，在详细的岩相学和矿相学观察基础上，开展全岩铂族元素、Re-Os同位素及精细的矿物原位地球化学分析。结合结晶热力学模拟计算，系统探讨岩体岩浆起源、演化过程以及成岩成矿模式。并通过综合对比不同构造背景下典型层状侵入岩的成岩成矿特征，确定毕机沟岩体成岩成矿背景，为理解新元古代扬子板块北缘岩浆－构造性质，恢复构造演化格局提供新的科学视角。此外，对毕机沟岩体岩石成因的研究和相关矿床成矿模式的建立，可以为丰富扬子板块北缘早期成矿多样性及金属成矿理论提供参考依据。