Formation and evolution of supercritical geofluid  

作　　者：Huaiwei NI Yilin XIAO Xiaolin XIONG Xiandong LIU Chunxiao GAO Yi-Xiang CHEN Yunguo LI Wan-Cai LI Xuan GUO Yang-Yang WANG Dong-Bo TAN Li ZHANG 

机构地区：[1]State Key Laboratory of Lithospheric and Environmental Coevolution,University of Science and Technology of China,Hefei,230026,China [2]Deep Space Exploration Laboratory/School of Earth and Space Sciences,University of Science and Technology of China,Hefei,230026,China [3]Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou,510640,China [4]School of Earth Sciences and Engineering,Nanjing University,Nanjing,210023,China [5]State Key Lab of Superhard Materials,Jilin University,Changchun,130012,China

出　　处：《Science China Earth Sciences》2025年第1期39-51,共13页中国科学(地球科学英文版)

基　　金：supported by the National Key R&D Program of China(Grant No.2018YFA0702700);the National Natural Science Foundation of China(Grant Nos.42330301,42488101);the Fundamental Research Funds for the Central Universities of China(Grant No.WK3410000019)。

摘　　要：In this work,we provide a comprehensive review on the formation,evolution,properties,and effects of supercritical geofluid.In Earth's interior,enhanced miscibility between H_(2)O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H_(2)O and silicate solute.The formation of supercritical geofluid in magmatic-hydrothermal systems,typified by pegmatite system,is governed by meltfluid critical curve.The formation of supercritical geofluid in metamorphic systems,typified by subducted slab,is governed by the second critical end point.Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths,but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth.A major presence of both H_(2)O and depolymerized structural units(monomers,dimers,etc.)endows supercritical geofluid with unique physical properties including low density,low elastic moduli,low viscosity,high diffusivity,and high electrical conductivity.Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements.The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts,and this could give an explanation of the oxidation of arc magmas.Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network.Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid.Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab,and can be linked with intermediate-focus earthquakes.Supercritical geofluid may have played a crucial role in the formation of pegmatites and associated ore deposits.

关 键 词：Supercritical geofluid MISCIBILITY Subduction zone PEGMATITE 

分 类 号：P31[天文地球—固体地球物理学]