Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada
The siliciclastic Wishart Formation of the Early Proterozic Labrador trough is high-energy shelf deposit. Wishart sandstones contain both interstitial chert with textures of void-filling cement and thin chert intercalations contaminated with siliciclastic mud. Although volumetrically minor, these ch...
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ftoberlincollege:oai:digitalcommons.oberlin.edu:faculty_schol-4458 2023-05-15T17:22:51+02:00 Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada Simonson, Bruce M. 1985-02-01T08:00:00Z https://digitalcommons.oberlin.edu/faculty_schol/3459 https://doi.org/10.1111/j.1365-3091.1985.tb00490.x English eng Digital Commons at Oberlin https://digitalcommons.oberlin.edu/faculty_schol/3459 https://dx.doi.org/10.1111/j.1365-3091.1985.tb00490.x Faculty & Staff Scholarship Silica Geology Stratigraphic--Proterozoic High energy forming Reefs text 1985 ftoberlincollege https://doi.org/10.1111/j.1365-3091.1985.tb00490.x 2022-11-26T18:27:52Z The siliciclastic Wishart Formation of the Early Proterozic Labrador trough is high-energy shelf deposit. Wishart sandstones contain both interstitial chert with textures of void-filling cement and thin chert intercalations contaminated with siliciclastic mud. Although volumetrically minor, these cherts occur in several thin, areally extensive stratigraphic mud. Although volumetrically minor, these cherts occur in several thin, areally extensive stratigraphic intervals. The Wishart contains intraclasts of both the chertcemented sandstone and the impure chert layers (as well as several other types of chert sand and gravel). This suggests the cherts formed penecontemporaneously, which is consistent with the absence of any signs of replacement in all but one of the chert types and the clear-cut distinctions between chert types, even where they are side by side in a single thin section. The origin which appears to be most compatible with available evidence is that the cherts represent silica precipitated from thermal waters that rose through the sediments of the Wishart shelf and discharged precipitated from thermal waters that rose through the sediments of the Wishart shelf and discharged into suprajacent seawater. A biogenic origin is unlikely in view of the lack of appropriate organisms during the Early Proterozic and the rapidity with which the cements formed. A volcanogenic origin is likely because volcaniclastic tezxtures are plentiful in associated formations but absent from the Wishart. Precipitation induced by evaporative concentration in unlikely in view of the widespread evidence of tidal currents and the lack of evidence of desiccation in the Wishart. Finally, the cherts are not restricted to the lowest-energy faces, and therefore they presumably did not accumulate as a background sediment. Deposition of silica above the sediment/water interface was probably made possible by ambient concentrations of silica that were significantly higher than those of Phancrozoic seawater. Cherts with similar textures ... Text Newfoundland Digital Commons at Oberlin (Oberlin College) Canada Newfoundland Sedimentology 32 1 23 40 |
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Open Polar |
collection |
Digital Commons at Oberlin (Oberlin College) |
op_collection_id |
ftoberlincollege |
language |
English |
topic |
Silica Geology Stratigraphic--Proterozoic High energy forming Reefs |
spellingShingle |
Silica Geology Stratigraphic--Proterozoic High energy forming Reefs Simonson, Bruce M. Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada |
topic_facet |
Silica Geology Stratigraphic--Proterozoic High energy forming Reefs |
description |
The siliciclastic Wishart Formation of the Early Proterozic Labrador trough is high-energy shelf deposit. Wishart sandstones contain both interstitial chert with textures of void-filling cement and thin chert intercalations contaminated with siliciclastic mud. Although volumetrically minor, these cherts occur in several thin, areally extensive stratigraphic mud. Although volumetrically minor, these cherts occur in several thin, areally extensive stratigraphic intervals. The Wishart contains intraclasts of both the chertcemented sandstone and the impure chert layers (as well as several other types of chert sand and gravel). This suggests the cherts formed penecontemporaneously, which is consistent with the absence of any signs of replacement in all but one of the chert types and the clear-cut distinctions between chert types, even where they are side by side in a single thin section. The origin which appears to be most compatible with available evidence is that the cherts represent silica precipitated from thermal waters that rose through the sediments of the Wishart shelf and discharged precipitated from thermal waters that rose through the sediments of the Wishart shelf and discharged into suprajacent seawater. A biogenic origin is unlikely in view of the lack of appropriate organisms during the Early Proterozic and the rapidity with which the cements formed. A volcanogenic origin is likely because volcaniclastic tezxtures are plentiful in associated formations but absent from the Wishart. Precipitation induced by evaporative concentration in unlikely in view of the widespread evidence of tidal currents and the lack of evidence of desiccation in the Wishart. Finally, the cherts are not restricted to the lowest-energy faces, and therefore they presumably did not accumulate as a background sediment. Deposition of silica above the sediment/water interface was probably made possible by ambient concentrations of silica that were significantly higher than those of Phancrozoic seawater. Cherts with similar textures ... |
format |
Text |
author |
Simonson, Bruce M. |
author_facet |
Simonson, Bruce M. |
author_sort |
Simonson, Bruce M. |
title |
Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada |
title_short |
Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada |
title_full |
Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada |
title_fullStr |
Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada |
title_full_unstemmed |
Sedimentology of cherts in the Early Proterozoic Wishart Formation, Quebec–Newfoundland, Canada |
title_sort |
sedimentology of cherts in the early proterozoic wishart formation, quebec–newfoundland, canada |
publisher |
Digital Commons at Oberlin |
publishDate |
1985 |
url |
https://digitalcommons.oberlin.edu/faculty_schol/3459 https://doi.org/10.1111/j.1365-3091.1985.tb00490.x |
geographic |
Canada Newfoundland |
geographic_facet |
Canada Newfoundland |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Faculty & Staff Scholarship |
op_relation |
https://digitalcommons.oberlin.edu/faculty_schol/3459 https://dx.doi.org/10.1111/j.1365-3091.1985.tb00490.x |
op_doi |
https://doi.org/10.1111/j.1365-3091.1985.tb00490.x |
container_title |
Sedimentology |
container_volume |
32 |
container_issue |
1 |
container_start_page |
23 |
op_container_end_page |
40 |
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1766109744695607296 |