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Title: Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba

Abstract

Fluid inclusions from the tourmaline phase of alteration of the footwall amphibolite from the Tanco zoned granitic pegmatite lie in the system H{sub 2}O-CH{sub 4}-NaCl-CO{sub 2}. These inclusions contain a liquid and vapor phase at room temperature and develop a second liquid phase on cooling in the range {minus}77 to {minus}95{degree}C: the second liquid and the vapor are methane. Isochores for inclusions showing vapor phase (CH{sub 4}) homogenization were constructed from the equations of Jacobs and Kerrick (1981). The intersections of these isochores with the univariant melting curves for methane clathrate hydrates give estimates of salinity for the inclusions of between 7 and 10 equivalent wt.% NaCl, which are lower than those derived from measurement of the depression of the melting point of ice; a result consistent with salt exclusion by clathrate. The bulk composition of the fluid is estimated to be 91 mol.% H{sub 2}O, 6 mol.% CH{sub 4}, 2 equiv. mol.% NaCl and <1 mol.% CO{sub 2}. Total homogenization temperatures have a mean value of 371{degree}C {plus minus} 36{degree}C. Calculation of f{sub O2} from the bulk inclusion composition gives values near WI at these conditions which is unreasonably low for fluids derived from the pegmatite, which were probablymore » between QFM and HM. The metasomatic fluids may have resulted from fluid mixing in the wall rock immediately adjacent to the pegmatite. The fluid derived from the pegmatite, a H{sub 2}O-CO{sub 2} fluid, introduced the B necessary to form tourmaline in the amphibolite. Supporting evidence is provided by pegmatite wall zone fluids with higher CH{sub 4} than the bulk of the pegmatite H{sub 2}O-CO{sub 2} fluids, suggesting marginal fluid contamination.« less

Authors:
;  [1]
  1. Univ. of Toronto, Ontario (Canada)
Publication Date:
OSTI Identifier:
5222125
Resource Type:
Journal Article
Journal Name:
Geochimica et Cosmochimica Acta; (USA)
Additional Journal Information:
Journal Volume: 52:5; Journal ID: ISSN 0016-7037
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; INCLUSIONS; CHEMICAL COMPOSITION; MANITOBA; PEGMATITES; HYDROTHERMAL ALTERATION; PETROGENESIS; CARBON DIOXIDE; CRYSTALLIZATION; EQUILIBRIUM; FLUIDS; GEOCHEMISTRY; GEOTHERMOMETRY; METAMORPHISM; METHANE; PHASE STUDIES; SALINITY; SODIUM CHLORIDES; TOURMALINE; WATER; ALKALI METAL COMPOUNDS; ALKANES; ALUMINIUM COMPOUNDS; ALUMINIUM SILICATES; BORON COMPOUNDS; BORON SILICATES; CANADA; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMISTRY; CHLORIDES; CHLORINE COMPOUNDS; GRANITES; HALIDES; HALOGEN COMPOUNDS; HYDROCARBONS; HYDROGEN COMPOUNDS; IGNEOUS ROCKS; MINERALS; NORTH AMERICA; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PHASE TRANSFORMATIONS; PLUTONIC ROCKS; ROCKS; SILICATE MINERALS; SILICATES; SILICON COMPOUNDS; SODIUM COMPOUNDS; 580000* - Geosciences

Citation Formats

Thomas, A V, and Spooner, E T. Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba. United States: N. p., 1988. Web. doi:10.1016/0016-7037(88)90261-X.
Thomas, A V, & Spooner, E T. Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba. United States. https://doi.org/10.1016/0016-7037(88)90261-X
Thomas, A V, and Spooner, E T. Sun . "Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba". United States. https://doi.org/10.1016/0016-7037(88)90261-X.
@article{osti_5222125,
title = {Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba},
author = {Thomas, A V and Spooner, E T},
abstractNote = {Fluid inclusions from the tourmaline phase of alteration of the footwall amphibolite from the Tanco zoned granitic pegmatite lie in the system H{sub 2}O-CH{sub 4}-NaCl-CO{sub 2}. These inclusions contain a liquid and vapor phase at room temperature and develop a second liquid phase on cooling in the range {minus}77 to {minus}95{degree}C: the second liquid and the vapor are methane. Isochores for inclusions showing vapor phase (CH{sub 4}) homogenization were constructed from the equations of Jacobs and Kerrick (1981). The intersections of these isochores with the univariant melting curves for methane clathrate hydrates give estimates of salinity for the inclusions of between 7 and 10 equivalent wt.% NaCl, which are lower than those derived from measurement of the depression of the melting point of ice; a result consistent with salt exclusion by clathrate. The bulk composition of the fluid is estimated to be 91 mol.% H{sub 2}O, 6 mol.% CH{sub 4}, 2 equiv. mol.% NaCl and <1 mol.% CO{sub 2}. Total homogenization temperatures have a mean value of 371{degree}C {plus minus} 36{degree}C. Calculation of f{sub O2} from the bulk inclusion composition gives values near WI at these conditions which is unreasonably low for fluids derived from the pegmatite, which were probably between QFM and HM. The metasomatic fluids may have resulted from fluid mixing in the wall rock immediately adjacent to the pegmatite. The fluid derived from the pegmatite, a H{sub 2}O-CO{sub 2} fluid, introduced the B necessary to form tourmaline in the amphibolite. Supporting evidence is provided by pegmatite wall zone fluids with higher CH{sub 4} than the bulk of the pegmatite H{sub 2}O-CO{sub 2} fluids, suggesting marginal fluid contamination.},
doi = {10.1016/0016-7037(88)90261-X},
url = {https://www.osti.gov/biblio/5222125}, journal = {Geochimica et Cosmochimica Acta; (USA)},
issn = {0016-7037},
number = ,
volume = 52:5,
place = {United States},
year = {1988},
month = {5}
}