Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada
Structural, metamorphic, and UPb geochronological data bear on the distinction between Archean and Paleoproterozoic tectonism along the southeastern margin of the Rae Province on Baffin Island. Archean rocks include ca. 3.02.8 Ga gneiss, two greenstone belts of the Mary River Group, and various yo...
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crcansciencepubl:10.1139/e03-040 2024-09-15T17:57:04+00:00 Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada Bethune, K M Scammell, R J 2003 http://dx.doi.org/10.1139/e03-040 http://www.nrcresearchpress.com/doi/pdf/10.1139/e03-040 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 40, issue 8, page 1111-1135 ISSN 0008-4077 1480-3313 journal-article 2003 crcansciencepubl https://doi.org/10.1139/e03-040 2024-07-25T04:10:03Z Structural, metamorphic, and UPb geochronological data bear on the distinction between Archean and Paleoproterozoic tectonism along the southeastern margin of the Rae Province on Baffin Island. Archean rocks include ca. 3.02.8 Ga gneiss, two greenstone belts of the Mary River Group, and various younger granitoid intrusions. In the greenstone belts, intermediatefelsic volcanism (2.742.725 Ga) was accompanied and outlasted by calc-alkaline plutonism (2.732.715 Ga). Deformation, low- to medium-pressure metamorphism, and peraluminous plutonism followed at ca. 2.7 Ga. Archean rocks and the locally overlying Piling Group (ca. 2.21.9 Ga) were deformed and metamorphosed together during development of the Paleoproterozoic Foxe fold belt. Tectonism is linked to the Isortoq fault zone, a major southeast-dipping structure marking an abrupt northwestward transition to granulite facies. Within a 5-km-wide zone, tight folds of the Archean Mary River Group give way down-section to moderately southeast-dipping, highly transposed, high-grade gneissic rocks. Several northeast- and north-striking ductilebrittle faults, some recording normal-sinistral oblique displacement, truncate early gneissosity and folds. This progression, along with UPb metamorphic ages, suggests early northwest-directed thrusting, starting at ca. 1.85 Ga, with peak metamorphism in the footwall at ca. 1.831.82 Ga. Later extensional displacement caused juxtaposition of lower grade on higher grade rocks. Archean ages of metamorphism (and deformation) are well preserved only in the hanging wall and the youngest metamorphic ages are restricted to the footwall. The data indicate that mountain building involved thrust-related thickening followed by gravitational collapse, a sequence characteristic of Phanerozoic orogens. Article in Journal/Newspaper Baffin Island Baffin Isortoq Canadian Science Publishing Canadian Journal of Earth Sciences 40 8 1111 1135 |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Structural, metamorphic, and UPb geochronological data bear on the distinction between Archean and Paleoproterozoic tectonism along the southeastern margin of the Rae Province on Baffin Island. Archean rocks include ca. 3.02.8 Ga gneiss, two greenstone belts of the Mary River Group, and various younger granitoid intrusions. In the greenstone belts, intermediatefelsic volcanism (2.742.725 Ga) was accompanied and outlasted by calc-alkaline plutonism (2.732.715 Ga). Deformation, low- to medium-pressure metamorphism, and peraluminous plutonism followed at ca. 2.7 Ga. Archean rocks and the locally overlying Piling Group (ca. 2.21.9 Ga) were deformed and metamorphosed together during development of the Paleoproterozoic Foxe fold belt. Tectonism is linked to the Isortoq fault zone, a major southeast-dipping structure marking an abrupt northwestward transition to granulite facies. Within a 5-km-wide zone, tight folds of the Archean Mary River Group give way down-section to moderately southeast-dipping, highly transposed, high-grade gneissic rocks. Several northeast- and north-striking ductilebrittle faults, some recording normal-sinistral oblique displacement, truncate early gneissosity and folds. This progression, along with UPb metamorphic ages, suggests early northwest-directed thrusting, starting at ca. 1.85 Ga, with peak metamorphism in the footwall at ca. 1.831.82 Ga. Later extensional displacement caused juxtaposition of lower grade on higher grade rocks. Archean ages of metamorphism (and deformation) are well preserved only in the hanging wall and the youngest metamorphic ages are restricted to the footwall. The data indicate that mountain building involved thrust-related thickening followed by gravitational collapse, a sequence characteristic of Phanerozoic orogens. |
format |
Article in Journal/Newspaper |
author |
Bethune, K M Scammell, R J |
spellingShingle |
Bethune, K M Scammell, R J Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada |
author_facet |
Bethune, K M Scammell, R J |
author_sort |
Bethune, K M |
title |
Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada |
title_short |
Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada |
title_full |
Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada |
title_fullStr |
Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada |
title_full_unstemmed |
Distinguishing between Archean and Paleoproterozoic tectonism, and evolution of the Isortoq fault zone, Eqe Bay area, north-central Baffin Island, Canada |
title_sort |
distinguishing between archean and paleoproterozoic tectonism, and evolution of the isortoq fault zone, eqe bay area, north-central baffin island, canada |
publisher |
Canadian Science Publishing |
publishDate |
2003 |
url |
http://dx.doi.org/10.1139/e03-040 http://www.nrcresearchpress.com/doi/pdf/10.1139/e03-040 |
genre |
Baffin Island Baffin Isortoq |
genre_facet |
Baffin Island Baffin Isortoq |
op_source |
Canadian Journal of Earth Sciences volume 40, issue 8, page 1111-1135 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e03-040 |
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Canadian Journal of Earth Sciences |
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40 |
container_issue |
8 |
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1111 |
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1135 |
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1810433257942024192 |