论文部分内容阅读
板块俯冲是地球内部系统最为宏伟的地质过程,是实现地球表面-内部物质和能量交换、大陆地壳生长以及壳/幔相互作用的重要场所,广泛深刻地影响着地壳的增生与消亡、火山和地震活动、地球表层物质循环、矿产资源分布、大陆造山运动、大陆的聚合及裂解等与人类生活息息相关的地质过程,因此一直是固体地球科学研究所关注的热点.20世纪80年代中期关于大陆地壳能够俯冲进入地幔深度并大部分折返地表的发现,是俯冲带研究和板块构造理论的革命性进展.相较于俯冲洋壳,大陆地壳具有较冷、较干、较轻的特点,同时,俯冲陆壳与地幔相比具有更加不均一的性质和化学成分以及同位素组成,因此在局部而言会对上覆大陆岩石圈和大陆板块汇聚边界的结构、组成、变形和演化进程造成巨大影响.在大陆俯冲过程中,拆离的地壳碎块和岩片在俯冲隧道内受到构造剪切,促使其经历变质脱水和部分熔融,产生各种流体和熔体.这些熔/流体的产生和演化在俯冲带壳/幔相互作用过程中扮演着非常重要的角色,是俯冲过程中发生元素迁移、同位素分馏以及交代上覆地幔楔的不可或缺的介质.本文综合国际上近年来有关俯冲带研究的最新进展,总结了有关俯冲带流体和熔体的类型、存在条件、化学组成、熔体/流体-地幔相互作用的特点,同时对于与大陆俯冲带流体相关的特征性元素(Nb-Ta-V)迁移和最新的非传统稳定同位素(Li-Mg)研究进行了系统介绍,期望为中国读者较全面地认识板块俯冲过程中的熔/流体活动和元素迁移以及了解并运用Li和Mg同位素作为新兴的示踪手段提供一定帮助.
Plate subduction is the most magnificent geologic process in the Earth’s interior system. It is an important site for the Earth’s surface-internal material and energy exchange, the continental crust growth and the interaction between the crust and the mantle. It has extensive and profound impacts on the crustal proliferation and extinction. Volcanoes and earthquakes Activities, the Earth’s surface material circulation, the distribution of mineral resources, the mainland orogeny, the mainland’s polymerization and cracking and other geological processes and human life is closely related, so it has been the focus of solid earth science research hot .1980s on the continental crust can The subduction into the depth of the mantle and the discovery of most of the reentry surface are the revolutionary advances in the study of the subduction zone and plate tectonics. Compared with the subducted oceanic crust, the continental crust has the characteristics of colder, drier and lighter. At the same time, The more heterogeneous nature and chemical composition and isotopic composition of the crust than the mantle can have a major impact locally on the structure, composition, deformation and evolution of the convergent boundary of the overlying continental lithosphere and continental plate. During subduction, the detachment of crustal crust and rock fragments are confined within the subducted tunnel Shearing, causing it to undergo metamorphic dehydration and partial melting, resulting in various fluids and melts.The production and evolution of these melts / fluids play a very important role in the subductional crust / mantle interaction and occur during subduction Element migration, isotopic fractionation and an indispensable medium for the overlying mantle wedge.In this paper, the latest advances in the research on the subduction zone in recent years are summarized in this paper. The types, existing conditions, chemical composition, (Nb-Ta-V) migration and the latest unconventional stable isotope (Li-Mg) studies in the continental subduction zone are systematically introduced. The expectation is that It is helpful for Chinese readers to understand the melt / fluid activity and element migration during plate subduction and understand and use Li and Mg isotopes as a new tracer.