Chemical reaction diversity of geofluids revealed by hydrothermal experiments under sub- and supercritical states

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16 Citations (Scopus)

Abstract

Hydrothermal experiments of dissolution of granite and quartz with pure water up to 600°C and 60MPa were carried out in order to evaluate chemical reaction under sub- and supercritical conditions. The supercritical region beyond the critical point for water has been inferred to be a homogeneous state, which does not correspond to either a true liquid phase, or a true vapor phase. Results of dissolution experiments of granite and quartz in a supercritical state (artificially defined as higher pressures and temperatures than the critical point), show this fluid can be subdivided into two apparent phases comprising a 'liquid-like' region and a 'vapor-like' region. Chemical phenomena with respect to dissolution reactions in the 'liquid-like' region are more similar to those of subcritical water, whilst those reactions in the 'vapor-like' region even in the supercritical state are considered to be weak. The critical point of various kinds of geofluids, composed of solutions in the H2O-CO2-NaCl system was experimentally determined using a visible type autoclave. Chemical reaction diversity, depending on location of the critical point for a given solution and apparent phase boundary in terms of chemical reaction within the supercritical state, was recognized by hydrothermal experiments.

Original languageEnglish
Pages (from-to)6-15
Number of pages10
JournalIsland Arc
Volume16
Issue number1
DOIs
Publication statusPublished - 2007 Mar 1

Keywords

  • Chemical reaction
  • Critical point
  • Dissolution
  • Geofluid
  • Hydrothermal experiment
  • Supercritical state
  • Water-rock interaction

ASJC Scopus subject areas

  • Geology

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