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On the origin of CO 2 ‐rich fluid inclusions in migmatites
Author(s) -
HOLLISTER L.S.
Publication year - 1988
Publication title -
journal of metamorphic geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.639
H-Index - 114
eISSN - 1525-1314
pISSN - 0263-4929
DOI - 10.1111/j.1525-1314.1988.tb00434.x
Subject(s) - plagioclase , geology , migmatite , inclusion (mineral) , fluid inclusions , quartz , mineralogy , biotite , melt inclusions , geochemistry , analytical chemistry (journal) , mantle (geology) , chemistry , metamorphic rock , chromatography , paleontology , gneiss
Nearly pure CO 2 fluid inclusions are abundant in migmatites although H 2 O‐rich fluids are predicted from the phase equilibria. Processes which may play a role in this observation include (1) the effects of decompression on melt, (2) generation of a CO 2 ‐bearing volatile phase by the reaction graphite + quartz + biotite + plagioclase = melt + orthopyroxene + CO 2 ‐rich vapour, (3) selective leakage of H 2 O from CO 2 + H 2 O inclusions when the pressure in the inclusion exceeds the confining pressure during decompression, and (4) enrichment of grain‐boundary vapour in CO 2 by subsolidus retrograde hydration reactions.