郑永飞等1999-变质流体地球化学-从静态定性流向动态定量.pdfVIP

1000-0569/1999/015(04)-0564-75 Acta Petrologica Sinica ~ ...G ff-tll Department of Earth and Space Sciences. University of Science and Technology of China, Hefei 230026. 1999-01-18 /t#;, 1999-04-02 ;tl, Zheng Yongfei. Fu Bin and Wei Chunsheng. 1999. Geochemistry of metamorphic fluids: from static-qualitative analysis to dynamic-quantitative study. Acta Petrologica Sinica. 15(4) :564 575 Abstract Numerous studies of the mineralogical evolution of metamorphic rocks have resulted in recognition of the impor- tance of fluid flow in the processes of metamorphism. Mineral paragenesis. geochemical and isotopic data can be used to iden- tify where fluid flowed in metamorphic terranes. to measure the amount of fluid. to constrain the direction of fluid flow rela- tive to temperature and pressure gradients and lithologic contacts. and to determine the ages of flow. Under special combina- tions of mineralogy. fluid composition. temperature and pressure. fluid can flow through a static. interconnected network of microscopic tubes at grain corners. Metamorphic fluid flow plays a significant role in heat and mass transfer in Earths crust and in the mechanisms and rates of deformation. It has been recognized that there is a large amount of aqueous fluid in a variety of crustal environments. Regional and contact metamorphic rocks have time-integrated fluxes far greater than amounts that can be supplied by dehydration of imme- diately subjacent rocks. The types of evidence supporting high water fluexes are numerous and varied. including petrologic. mineralogical, textural, microstructural, and stable isotopic data. Permeability enhancement may be the principal mecha- nisms to facilitate large fluid fluxes. In order to und