The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada
Multiple occurrences of bedded barite (BaSO4) are preserved in mudstones of the upper-most Canol Formation (Frasnian) of the Selwyn Basin (Canada). Samples of barite were collected from eight sites (seven measured sections), and examined using petrographic and isotopic techniques (87Sr/86Sr, δ34S an...
Published in: | Marine and Petroleum Geology |
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2017
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_2182890 2023-05-15T17:46:46+02:00 The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada Fernandes, N. Gleeson, S. Magnall, J. Creaser, R. Martel, E. Fischer, B. Sharp, R. 2017 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2182890 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.marpetgeo.2017.04.006 info:eu-repo/semantics/altIdentifier/urn/http://doi.crossref.org/servlet/query?format=unixref&pid=bib@gfz-potsdam.de&id=10.1016/j.marpetgeo.2017.04.006 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2182890 Marine and Petroleum Geology info:eu-repo/semantics/article 2017 ftgfzpotsdam https://doi.org/10.1016/j.marpetgeo.2017.04.006 2022-09-14T05:53:47Z Multiple occurrences of bedded barite (BaSO4) are preserved in mudstones of the upper-most Canol Formation (Frasnian) of the Selwyn Basin (Canada). Samples of barite were collected from eight sites (seven measured sections), and examined using petrographic and isotopic techniques (87Sr/86Sr, δ34S and δ18O values) to determine whether the barite has a diagenetic or hydrothermal origin. Barite at all locations occurs in two morphologies: (1) laminated barite composed of thin layers of microcrystalline barite with lesser amounts of pyrite and hyalophane (Ba-K-feldspar) interlaminated with mudstone, and (2) nodular barite consisting of barite, hyalophane, cymrite (hydrous Ba-silicate) and minor pyrite. At the Cowan occurrence, one sample has a mineral assemblage comprising barite and nodular barium carbonates (witherite, norsethite). The δ34S and δ18O values of the laminated barite co-vary, and range between +24.1 and +35.3‰ and +14.8 to +18.3‰ respectively, with the exception of one sample with δ34S and δ18O values of +32.9‰ and −0.5‰. The laminated samples have an average 87Sr/86Sr of 0.7085 (n = 8), which is consistent with Frasnian seawater (0.7081) that has undergone some minor water sediment interaction during early diagenesis. The nodular barite has highly variable δ34S (+4.8 to +56.5‰) and δ18O (+9.2 to +19.3‰) values, which developed from more evolved diagenetic pore fluids with limited sulphate re-supply (i.e., as a relatively closed system). In these conditions sulphate reduction likely occurred at a slower rate, and the sulphate in the barite records both kinetic (δ34SSO4) and equilibrium (δ18OSO4) isotope effects. One sample of nodular barite has a 87Sr/86Sr ratio of 0.7086. The single sample with a barite and barium-carbonate assemblage at Cowan has a 87Sr/86Sr ratio of 0.7133, a δ34S value of +23.9‰, and a δ18O value of +10.7‰ and may represent a local hydrothermal event at this site. Our data supports the interpretation that the barite horizon is a stratigraphic marker throughout the Canol Formation. ... Article in Journal/Newspaper Northwest Territories GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Northwest Territories Canol Canada Selwyn ENVELOPE(-138.287,-138.287,62.799,62.799) Marine and Petroleum Geology 85 1 15 |
institution |
Open Polar |
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GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
unknown |
description |
Multiple occurrences of bedded barite (BaSO4) are preserved in mudstones of the upper-most Canol Formation (Frasnian) of the Selwyn Basin (Canada). Samples of barite were collected from eight sites (seven measured sections), and examined using petrographic and isotopic techniques (87Sr/86Sr, δ34S and δ18O values) to determine whether the barite has a diagenetic or hydrothermal origin. Barite at all locations occurs in two morphologies: (1) laminated barite composed of thin layers of microcrystalline barite with lesser amounts of pyrite and hyalophane (Ba-K-feldspar) interlaminated with mudstone, and (2) nodular barite consisting of barite, hyalophane, cymrite (hydrous Ba-silicate) and minor pyrite. At the Cowan occurrence, one sample has a mineral assemblage comprising barite and nodular barium carbonates (witherite, norsethite). The δ34S and δ18O values of the laminated barite co-vary, and range between +24.1 and +35.3‰ and +14.8 to +18.3‰ respectively, with the exception of one sample with δ34S and δ18O values of +32.9‰ and −0.5‰. The laminated samples have an average 87Sr/86Sr of 0.7085 (n = 8), which is consistent with Frasnian seawater (0.7081) that has undergone some minor water sediment interaction during early diagenesis. The nodular barite has highly variable δ34S (+4.8 to +56.5‰) and δ18O (+9.2 to +19.3‰) values, which developed from more evolved diagenetic pore fluids with limited sulphate re-supply (i.e., as a relatively closed system). In these conditions sulphate reduction likely occurred at a slower rate, and the sulphate in the barite records both kinetic (δ34SSO4) and equilibrium (δ18OSO4) isotope effects. One sample of nodular barite has a 87Sr/86Sr ratio of 0.7086. The single sample with a barite and barium-carbonate assemblage at Cowan has a 87Sr/86Sr ratio of 0.7133, a δ34S value of +23.9‰, and a δ18O value of +10.7‰ and may represent a local hydrothermal event at this site. Our data supports the interpretation that the barite horizon is a stratigraphic marker throughout the Canol Formation. ... |
format |
Article in Journal/Newspaper |
author |
Fernandes, N. Gleeson, S. Magnall, J. Creaser, R. Martel, E. Fischer, B. Sharp, R. |
spellingShingle |
Fernandes, N. Gleeson, S. Magnall, J. Creaser, R. Martel, E. Fischer, B. Sharp, R. The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada |
author_facet |
Fernandes, N. Gleeson, S. Magnall, J. Creaser, R. Martel, E. Fischer, B. Sharp, R. |
author_sort |
Fernandes, N. |
title |
The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada |
title_short |
The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada |
title_full |
The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada |
title_fullStr |
The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada |
title_full_unstemmed |
The origin of Late Devonian (Frasnian) stratiform and stratabound mudstone-hosted barite in the Selwyn Basin, Northwest Territories, Canada |
title_sort |
origin of late devonian (frasnian) stratiform and stratabound mudstone-hosted barite in the selwyn basin, northwest territories, canada |
publishDate |
2017 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_2182890 |
long_lat |
ENVELOPE(-138.287,-138.287,62.799,62.799) |
geographic |
Northwest Territories Canol Canada Selwyn |
geographic_facet |
Northwest Territories Canol Canada Selwyn |
genre |
Northwest Territories |
genre_facet |
Northwest Territories |
op_source |
Marine and Petroleum Geology |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.marpetgeo.2017.04.006 info:eu-repo/semantics/altIdentifier/urn/http://doi.crossref.org/servlet/query?format=unixref&pid=bib@gfz-potsdam.de&id=10.1016/j.marpetgeo.2017.04.006 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2182890 |
op_doi |
https://doi.org/10.1016/j.marpetgeo.2017.04.006 |
container_title |
Marine and Petroleum Geology |
container_volume |
85 |
container_start_page |
1 |
op_container_end_page |
15 |
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1766150615748050944 |