扬子克拉通神农架地区新元古代基性岩墙时代、成因和构造意义的地球化学研究

Neoproterozoic mafic dikes are widespread in the Shennongjia region, northern Yangtze craton. Comprehensive studies on these mafic dikes are expected to be critical for our understanding on the nature and tectonic setting of the Neoproterozoic mantle-derived igneous magmatism occurred at the northern Yangtze craton. However, documented works including high precision geochronology and geochemistry are relatively absent. The mafic dikes in the Shennongjia area are selected as our research objects. Based on detailed field geological investigation and indoor petrographic observation, their mineralogical features, alteration extent and relationship with the wall-rocks will be depicted. The comprehensive study comprises geochronology, whole-rock major- and trace elements as well as Sr-Nd-Pb isotopes, aiming to get their intrusive age, and geochemical data to discuss their petrogenesis, nature of mantle source and tectonic setting. Besides, combined with previously documented works of adjacent areas, a comparison on the diversity of lithospheric mantle between the Shennongjia and the Kongling areas is to be carried out to decipher the relationship of different blocks in the interior of the Yangtze craton. Accordingly, Neoproterozoic evolution of the primitive South China block and its connection with the evolution of Rodinia supercontinent are to be discussed.

扬子克拉通北缘神农架地区出露了大量新元古代基性岩墙和岩脉，这些基性侵入岩对认识扬子克拉通北缘新元古代幔源岩浆作用性质及构造环境均具有重要意义，然而它们的高精度年代学和地球化学数据目前仍相对缺乏。本研究以神农架地区新元古代基性侵入岩为研究对象，通过野外宏观露头观察和详细的镜下岩相学研究，确定其与围岩之间的相互关系、矿物构成和蚀变情况；采用高精度同位素年代学方法，查明其侵位时代；结合全岩样品的元素和Sr-Nd-Pb同位素地球化学特征，了解基性岩墙的岩石成因、地幔源区特征及其大地构造背景。结合申请者和前人在本地区和邻区已有的研究积累，对比扬子克拉通神农架地区和崆岭地区新元古代岩石圈地幔特征与异同，认识扬子克拉通内部不同区块之间的相互关系，进而探讨统一华南陆块在Rodinia超大陆演化全球构造背景下的形成和早期演化过程。

扬子克拉通北缘神农架地区出露了大量新元古代基性岩墙和岩脉，这些基性侵入岩对认识扬子克拉通北缘新元古代幔源岩浆作用性质及构造环境均具有重要意义，然而它们的高精度年代学和地球化学数据目前仍相对缺乏。本研究以神农架地区新元古代基性侵入岩为研究对象，通过野外宏观露头观察和详细的镜下岩相学研究，确定其与围岩之间的相互关系、矿物构成和蚀变情况；采用高精度同位素年代学方法，查明其侵位时代；结合全岩样品的元素和Sr-Nd-Pb同位素地球化学特征，了解基性岩墙的岩石成因、地幔源区特征及其大地构造背景。结合申请者和前人在本地区和邻区已有的研究积累，对比扬子克拉通神农架地区和崆岭地区新元古代岩石圈地幔特征与异同，认识扬子克拉通内部不同区块之间的相互关系，进而探讨统一华南陆块在Rodinia超大陆演化全球构造背景下的形成和早期演化过程。