俄－蒙阿尔泰古生代花岗岩时代、岩石成因及构造背景研究

The Central Asian Orogenic Belt (CAOB), different from classical collisional orogens, is one of the largest accretionary orogenic belt in the world, representing the most significant continental crustal growth in the Phanerozoic. Altai-Mongolian terrane is situated in the center of CAOB and consists of Chinese Altai, Russian Altai and Mongolian Altai. This terrane is characterized by voluminous granites that provide important information on the accretionary process of the CAOB. Although the granites of the Chinese Altai have been well studied, little is known about the granitic rocks outcropped both in the Russian and Mongolian Altai. The Chinese Altai is a good basis for comparative studies with the Russian and Mongolian Altai. Therefore, this research will involve an extensive study of granites in the Russian and Mongolian Altai, which is extremely important for understanding of the continental growth of the huge accretionary orogenic belt and also critical for constructing the geodynamic model of the CAOB. Systematic U-Pb and Hf isotopic analyses of zircons will be combined with geochemical, and Sr-Nd isotopic compositions of granites to decipher the age of the granites, the nature of the magma source and the tectonic backgroud of the Russian and Mongolian Altai. Using the Paleozoic granites of the Chinese Altai as a baseline,this research will define the tectonic background of the Paleozoic magmatic activity and study the process related to the Devonian ridge subduction and define the extent of such a process. Moreover, this study will provide important constraints on the crustal growth history of the whole CAOB.

中亚造山带是不同于经典碰撞造山带的增生型造山带，以显著的地壳垂向生长和侧向增生为标志。阿尔泰-蒙古地体是中亚造山带中部的重要地体,由中国、俄罗斯和蒙古阿尔泰构成。在该地体，不同类型的古生代花岗岩广泛发育，为认识中亚造山带的增生造山过程提供了重要的研究载体。目前，该地体内花岗岩区域间研究水平极不均衡，其中以中国阿尔泰花岗岩研究程度最高，最为系统，为区域间的对比研究打下了良好的基础。本项目拟对俄罗斯和蒙古阿尔泰古生代花岗岩开展详细的锆石年U-Pb年代学、元素地球化学和Nd-Hf同位素研究，以制约其岩石成因和形成时代，揭示深部地壳物质组成。通过与中国阿尔泰古生代花岗岩的综合对比研究，在境外阿尔泰继续探讨泥盆纪古洋中脊俯冲的可能性及岩浆响应记录并制约其影响范围，揭示整个阿尔泰-蒙古地体的构造属性及古生代地质演化历史，从而揭示中亚造山带中部地壳垂向生长和侧向增生过程，制约中亚造山带动力学演化模型。

中亚造山带是不同于经典碰撞造山带的增生型造山带,以显著的地壳垂向生长和侧向增生为标志。阿尔泰-蒙古地体是中亚造山带中部的重要地体,由中国、俄罗斯和蒙古 阿尔泰构成。在该地体,不同类型的古生代花岗岩广泛发育,为认识中亚造山带的增生造山 过程提供了重要的研究载体。目前,该地体内花岗岩区域间研究水平极不均衡,其中以中国 阿尔泰花岗岩研究程度最高,最为系统,为区域间的对比研究打下了良好的基础。本项目拟 对俄罗斯和蒙古阿尔泰古生代花岗岩开展详细的锆石年 U-Pb 年代学、元素地球化学和 Nd-Hf 同位素研究,以制约其岩石成因和形成时代,揭示深部地壳物质组成。通过与中国阿尔泰古 生代花岗岩的综合对比研究,在境外阿尔泰继续探讨泥盆纪古洋中脊俯冲的可能性及岩浆响 应记录并制约其影响范围,揭示整个阿尔泰-蒙古地体的构造属性及古生代地质演化历史, 从而揭示中亚造山带中部地壳垂向生长和侧向增生过程,制约中亚造山带动力学演化模型。