Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia
The Stirling Group consists of ca. 680 Ma volcanic and volcaniclastic rocks, interpreted to have been deposited in and around a trough flanked by felsic volcanic centres. The volcaniclastic rocks are dominated by lapilli tuff and tuffaceous litharenite sequences. The lapilli tuffs show some evidence...
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ftuninewbrunojs:oai:ojs.journals.lib.unb.ca:article/1996 2023-05-15T15:46:48+02:00 Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia MacDonald, Alan S. Barr, Sandra M. 1993-07-01 application/pdf https://journals.lib.unb.ca/index.php/ag/article/view/1996 eng eng Atlantic Geoscience Society https://journals.lib.unb.ca/index.php/ag/article/view/1996/2360 https://journals.lib.unb.ca/index.php/ag/article/view/1996 Copyright (c) 2015 Atlantic Geology Atlantic Geoscience; Vol. 29 No. 2 (1993) 2564-2987 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion research-article 1993 ftuninewbrunojs 2022-07-11T11:41:49Z The Stirling Group consists of ca. 680 Ma volcanic and volcaniclastic rocks, interpreted to have been deposited in and around a trough flanked by felsic volcanic centres. The volcaniclastic rocks are dominated by lapilli tuff and tuffaceous litharenite sequences. The lapilli tuffs show some evidence of subaqueous reworking but most may have originated as air-fall deposits. Sedimentary structures in the litharenites suggest subaqueous mass transport into the trough and deposition below wave base. Pyritic siltstone-chert-carbonate laminites, which are locally associated with the litharenites along the southeastern side of the trough adjacent to felsic volcanic centres, probably represent a mixture of fine-grained distal turbidites and chemical precipitates from subaqueous volcanic exhalations. The volcanic rocks of the Stirling Group do not show convincing evidence for subaqueous deposition: the felsic rocks appear to form subvolcanic intrusions and domes flanked by felsic crystal-rich lapilli tuff and rare welded(?) tuff; the mafic volcanic rocks are not pillowed but are closely associated with breccias which may have formed partly by quench fragmentation. The overall facies assemblage and its association with VMS Zn-Pb-Cu-Ag-Au mineralization are compatible with generation in an intra-arc basin. As the Stirling Group is significantly older than the volcanic belts which flank it, it may represent a tectonically displaced remnant of a pre-existing arc. RÉSUMÉ Le Groupe de Stirling consiste en roches volcaniques et volcanoclastiques d'environ 680 Ma, interprétées comme ayant été déposées à l'intérieur et autour d'une fosse bordée de centres volcaniques felsiques. Les roches volcanoclastiques sont dominées par des séequences de tufs à lapilli et de litharénites tuffacées. Les tufs à lapilli montrent quelques évidences de remaniement subaqueux mais la ... Article in Journal/Newspaper Breton Island University of New Brunswick: Centre for Digital Scholarship Journals Breton Island ENVELOPE(141.383,141.383,-66.800,-66.800) Fosse ENVELOPE(19.182,19.182,69.959,69.959) Stirling ENVELOPE(164.117,164.117,-71.550,-71.550) Atlantic Geology 29 2 |
institution |
Open Polar |
collection |
University of New Brunswick: Centre for Digital Scholarship Journals |
op_collection_id |
ftuninewbrunojs |
language |
English |
description |
The Stirling Group consists of ca. 680 Ma volcanic and volcaniclastic rocks, interpreted to have been deposited in and around a trough flanked by felsic volcanic centres. The volcaniclastic rocks are dominated by lapilli tuff and tuffaceous litharenite sequences. The lapilli tuffs show some evidence of subaqueous reworking but most may have originated as air-fall deposits. Sedimentary structures in the litharenites suggest subaqueous mass transport into the trough and deposition below wave base. Pyritic siltstone-chert-carbonate laminites, which are locally associated with the litharenites along the southeastern side of the trough adjacent to felsic volcanic centres, probably represent a mixture of fine-grained distal turbidites and chemical precipitates from subaqueous volcanic exhalations. The volcanic rocks of the Stirling Group do not show convincing evidence for subaqueous deposition: the felsic rocks appear to form subvolcanic intrusions and domes flanked by felsic crystal-rich lapilli tuff and rare welded(?) tuff; the mafic volcanic rocks are not pillowed but are closely associated with breccias which may have formed partly by quench fragmentation. The overall facies assemblage and its association with VMS Zn-Pb-Cu-Ag-Au mineralization are compatible with generation in an intra-arc basin. As the Stirling Group is significantly older than the volcanic belts which flank it, it may represent a tectonically displaced remnant of a pre-existing arc. RÉSUMÉ Le Groupe de Stirling consiste en roches volcaniques et volcanoclastiques d'environ 680 Ma, interprétées comme ayant été déposées à l'intérieur et autour d'une fosse bordée de centres volcaniques felsiques. Les roches volcanoclastiques sont dominées par des séequences de tufs à lapilli et de litharénites tuffacées. Les tufs à lapilli montrent quelques évidences de remaniement subaqueux mais la ... |
format |
Article in Journal/Newspaper |
author |
MacDonald, Alan S. Barr, Sandra M. |
spellingShingle |
MacDonald, Alan S. Barr, Sandra M. Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia |
author_facet |
MacDonald, Alan S. Barr, Sandra M. |
author_sort |
MacDonald, Alan S. |
title |
Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia |
title_short |
Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia |
title_full |
Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia |
title_fullStr |
Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia |
title_full_unstemmed |
Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia |
title_sort |
geological setting and depositional environment of the stirling group of southeastern cape breton island, nova scotia |
publisher |
Atlantic Geoscience Society |
publishDate |
1993 |
url |
https://journals.lib.unb.ca/index.php/ag/article/view/1996 |
long_lat |
ENVELOPE(141.383,141.383,-66.800,-66.800) ENVELOPE(19.182,19.182,69.959,69.959) ENVELOPE(164.117,164.117,-71.550,-71.550) |
geographic |
Breton Island Fosse Stirling |
geographic_facet |
Breton Island Fosse Stirling |
genre |
Breton Island |
genre_facet |
Breton Island |
op_source |
Atlantic Geoscience; Vol. 29 No. 2 (1993) 2564-2987 |
op_relation |
https://journals.lib.unb.ca/index.php/ag/article/view/1996/2360 https://journals.lib.unb.ca/index.php/ag/article/view/1996 |
op_rights |
Copyright (c) 2015 Atlantic Geology |
container_title |
Atlantic Geology |
container_volume |
29 |
container_issue |
2 |
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1766381517895892992 |