Dehydration at subduction zones and the geochemistry of slab fluids

作     者：Wancai Li Huaiwei Ni Wancai LI;Huaiwei NI

作者机构：CAS Key Laboratory of Crust-Mantle Materials and EnvironmentsSchool of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China CAS Center for Excellence in Comparative PlanetologyHefei230026China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2020年第63卷第12期

页      面：1925-1937页

核心收录：

学科分类：070904[理学-构造地质学] 070902[理学-地球化学] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0704[理学-天文学] 

基　　金：the National Natural Science Foundation of China(Grant Nos.41590622,41825004,41721002,41603057) the Fundamental Research Funds for the Central Universities of China(Grant Nos.WK2080000102,WK341000013) 

主　　题：Subduction zone Dehydration Slab fluids Volatiles Oxygen fugacity Acidity 

摘      要：Subducting oceanic slabs undergo metamorphic dehydration with the increase of temperature and pressure during *** is an essential step for element recycling,and slab fluids are critical agents for mediating slab-mantle *** is mainly controlled by the thermal structure of subduction zones and the stability of hydrous *** fore-arc depths,slab dehydration produces aqueous fluid with dissolved salts such as *** subduction proceeds deeper,the content of silicate components *** sub-arc and post-arc depths,a hydrous silicate melt is likely to form,or a supercritical fluid could arise from complete miscibility between silicates and H_(2)*** partitioning of elements between slab fluid and the residual solid rock is controlled by the type of fluid,and generally it is the supercritical fluid that is the most capable of mobilizing trace elements,being an effective carrier even for high field strength *** the chemistry of slab fluids relies on sophisticated integration of experiments,theoretical computation and investigation of natural rock *** contribution focuses on the content and speciation of key volatiles,including carbon,nitrogen and sulfur,in slab fluids as well as important fluid properties such as oxygen fugacity and *** properties of slab fluids show complicated variation under the control of mineral assemblages and T-P *** fluids at great depths of subductions have been inferred to be modestly alkaline and not necessarily very oxidizing as often *** progress in the research of slab dehydration and the chemistry and properties of slab fluids demands urgently the development of innovative experimental and computational technology including in situ analytical methods at high T-P.