【摘要】 安徽石马超高压变质地体经历 5次构造变形 ,其特征是由深层次挤压韧性变形到浅层次的伸展脆性变形。相应地发育有 5期流体 ,它们的演化规律为 :早期以硅酸盐熔体和流体熔融体为主 ,随后富CO2 流体占优势 ,后期H2 O溶液起主导作用。总体而言 ,从老到新流体均一温度和含盐度均由高变低。在构造作用和流体作用的共同推动下 ,石马超高压变质地体经历了复杂的演化过程 :洋壳俯冲 ,超高压榴辉岩形成与形变→陆壳碰撞 ,榴辉岩折返→地体构造分异 ,榴辉岩就位→地体均衡隆起 ,榴辉岩抬升→地体差异隆起 ,榴辉岩剥露。因此 ,流体作用在研究超高压变质地体中占有重要地位。流体直接影响超高压变质地体形成的物理化学环境 ,在分析其形成深度时 ,应充分考虑流体超压问题。总之 ,在超高压地体演化过程中 ,流体一直是积极推动其发展的最活跃的因素。更多还原

【Abstract】 Ultra-high-pressure (UHP) metamorphic terrain at Shima, Anhui Province experienced five phases of structural deformation which are characterized by the compressional ductile deformation at deep level and the extensional brittle deformation at shallow level. Five stages of fluids related to the structural deformation were developed. Silicate melt inclusions and fluid-melt immiscible inclusions are major fluids at the early stage. Subsequently CO 2-rich fluids are predominant. Aqueous fluids play a leading role at the later stage. Overall, homogenization temperatures and salinities of the fluid inclusions decrease from early- to late-stages. UHP metamorphic terrain at Shima went through a complicated evolution under the functions of tectonics and geofluids: subduction of oceanic crust, formation and deformation of eclogite →collision of the terrain and exhumation of eclogite → structural differentiation of the terrain and taking its place of eclogite → equilibrium upwarp of the terrain and uplift of eclogite → differential upwarp of the terrain and denudation of eclogite. The fluids,therefore, play an important role in study of UHP metamorphic terrain. The fluids have a direct influence on physical-chemical environments of formation of UHP metamorphic terrain, thus the superpressure of fluids needs to be fully considered in analysis of the formation depth of eclogite. In short, fluids are the most active factor during the evolution of UHP metamorphic terrain, propelling positively the development of the terrain.更多还原