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Melting behaviour and composition of aqueous fluid inclusions in fluorite and calcite; applications with the system H (sub 2) O-CaCl (sub 2) -NaCl

Erik W. Zwart and Jacques L. R. Touret
Melting behaviour and composition of aqueous fluid inclusions in fluorite and calcite; applications with the system H (sub 2) O-CaCl (sub 2) -NaCl
European Journal of Mineralogy (December 1994) 6 (6): 773-786

Abstract

In samples from the Zechstein formation in NW Germany, aqueous liquid-vapour (LV) as well as liquid-vapour-solid (LVS) inclusions in fluorite and calcite contain high salt concentrations, particularly belonging to the system H (sub 2) O-CaCl (sub 2) -NaCl. Emphasis is laid on the recognition of phase transitions and compositions by sequential heating and freezing. LV inclusions show a eutectic T near -52 degrees C, although the actual forming and melting of antarcticite could not be observed. Melting of ice (-27.8 to -24.4 degrees C) and hydrohalite (-15.8 to +15.4 degrees C) reveal the composition (16-19 wt.% NaCl, 7-11 wt.% CaCl (sub 2) ) when plotted on the relevant phase diagram. LVS inclusions belong to two categories: type I with the dissolution T of halite lower than the homogenization T (T (sub s) << T (sub h) ), shows the normal equilibrium melting (-31 to -26.3 degrees C melting of ice, -7.4 to -6.6 degrees C melting of hydrohalite) and contains 21-23 wt.% NaCl and 11-15 wt.% CaCl (sub 2) . Type II, with T (sub s) >> T (sub h) , shows non-equilibrium melting in the presence of a halite cube; the NaCl content is estimated at 21 wt.%. CO (sub 2) -CH (sub 4) clathrates form around the vapour phase and melt at -16.4 to -15 degrees C for LV inclusions and at -31 to -28.2 degrees C for LVS inclusions.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 6
Serial Issue: 6
Title: Melting behaviour and composition of aqueous fluid inclusions in fluorite and calcite; applications with the system H (sub 2) O-CaCl (sub 2) -NaCl
Affiliation: Vrije Universiteit, Institute of Earth Sciences, Amsterdam, Netherlands
Pages: 773-786
Published: 199412
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 29
Accession Number: 1995-007435
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: 1 table
N47°15'00" - N55°00'00", E05°49'60" - E15°00'00"
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199503
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