Thermodynamic forward modeling of retrogressive hydration reactions induced by geofluid infiltration

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• 作者：Tatsu Kuwatani ; Mitsuhiro Toriumi
• 关键词：Rehydration ; Forward modeling ; Greenschist ; Geofluid
• 刊名：Earth, Planets and Space
• 出版年：2017
• 出版时间：December 2017
• 年：2017
• 卷：69
• 期：1
• 全文大小：1562KB
• 刊物类别：Earth Sciences, general; Geology; Geophysics/Geodesy;
• 刊物主题：Earth Sciences, general; Geology; Geophysics/Geodesy;
• 出版者：Springer Berlin Heidelberg
• ISSN：1880-5981
• 卷排序：69

文摘

We have developed a new methodology for forward analysis of retrogressive hydration (rehydration) reactions by an improved thermodynamic forward modeling technique based on a differential thermodynamic approach (Gibbs’ method). Based on natural observations and theoretical considerations, the progress of a rehydration reaction is modeled by incorporating a change in the effective bulk composition on account of the breakdown of the non-equilibrated phase and the amount of water infiltration into the system. Forward analyses of rehydration reactions under greenschist-facies conditions show that (1) the reaction progress of rehydration is proportional to the external water supply, and (2) the mineral compositions of equilibrated minerals are mainly controlled by P–T conditions and are similar to those in the global equilibrium model. Calculated results are in accordance with natural observations of rehydration reactions in greenschist-facies rocks, which supports the validity of the proposed model. The proposed model can be used as a basic forward model for various inversion analyses and numerical simulations and thus to understand the distribution and behavior of geofluids.Graphical abstract.