Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology
In situ UPb sensitive high-resolution ion microprobe (SHRIMP) analyses of monazite from upper amphibolite-facies paragneiss of the Committee Bay supracrustal belt, central Rae domain, Canada, reveal three age populations: ca. 2350, 1850, and 1780 Ma. The ca. 1850 Ma age also corresponds to growth o...
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crcansciencepubl:10.1139/e04-054 2024-09-09T19:36:50+00:00 Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology Carson, Chris J Berman, Robert G Stern, Richard A Sanborn-Barrie, Mary Skulski, Tom Sandeman, Hamish AI 2004 http://dx.doi.org/10.1139/e04-054 http://www.nrcresearchpress.com/doi/pdf/10.1139/e04-054 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 41, issue 9, page 1049-1076 ISSN 0008-4077 1480-3313 journal-article 2004 crcansciencepubl https://doi.org/10.1139/e04-054 2024-07-25T04:10:06Z In situ UPb sensitive high-resolution ion microprobe (SHRIMP) analyses of monazite from upper amphibolite-facies paragneiss of the Committee Bay supracrustal belt, central Rae domain, Canada, reveal three age populations: ca. 2350, 1850, and 1780 Ma. The ca. 1850 Ma age also corresponds to growth of low Th/U zircon as indicated by UPb SHRIMP analyses of zircon separates from melanosome and leucosome. The contextual advantage of the in situ monazite analysis allows evaluation of the geochronological data in terms of the regional structural and metamorphic evolution. The region is dominated by a northeast-striking S 2 (±S 1 ) fabric, axial planar to tight, northwest-vergent F 2 folds. Early garnet is enveloped by this biotitesillimanite ± cordierite S 2 fabric. Garnet I hosts ca. 1850 Ma monazite inclusions (with ca. 2350 Ma cores), placing a maximum age on garnet I growth and S 2 development. D 2 metamorphic conditions progressed through ~3.5 kbar (1 kbar = 100 MPa) and 600 °C to near-peak conditions of ~5 kbar and 675 °C. A minimum age for S 2 is provided by unstrained ca. 1820 Ma monzogranite that locally, and regionally, truncates S 2 . Dominantly ca. 1780 Ma matrix monazite is interpreted to date post-S 2 garnet II and cordierite, which record ~5 kbar and 675 °C. These data indicate that the Committee Bay region experienced penetrative D 2 tectonometamorphism at ca. 18501820 Ma, with a subsequent static overprint. The absence of a ca. 1.85 Ga plutonic suite in the region suggests that low-pressure metamorphism was a response to thick-skinned crustal thickening initiated at ca. 1870 Ma. The new data highlight the importance of Paleoproterozoic reworking of the central Rae domain in the hinterland of the Trans-Hudson orogen. Article in Journal/Newspaper Committee Bay Canadian Science Publishing Canada Hudson Rae ENVELOPE(-116.053,-116.053,62.834,62.834) Committee Bay ENVELOPE(-86.899,-86.899,68.268,68.268) Canadian Journal of Earth Sciences 41 9 1049 1076 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
In situ UPb sensitive high-resolution ion microprobe (SHRIMP) analyses of monazite from upper amphibolite-facies paragneiss of the Committee Bay supracrustal belt, central Rae domain, Canada, reveal three age populations: ca. 2350, 1850, and 1780 Ma. The ca. 1850 Ma age also corresponds to growth of low Th/U zircon as indicated by UPb SHRIMP analyses of zircon separates from melanosome and leucosome. The contextual advantage of the in situ monazite analysis allows evaluation of the geochronological data in terms of the regional structural and metamorphic evolution. The region is dominated by a northeast-striking S 2 (±S 1 ) fabric, axial planar to tight, northwest-vergent F 2 folds. Early garnet is enveloped by this biotitesillimanite ± cordierite S 2 fabric. Garnet I hosts ca. 1850 Ma monazite inclusions (with ca. 2350 Ma cores), placing a maximum age on garnet I growth and S 2 development. D 2 metamorphic conditions progressed through ~3.5 kbar (1 kbar = 100 MPa) and 600 °C to near-peak conditions of ~5 kbar and 675 °C. A minimum age for S 2 is provided by unstrained ca. 1820 Ma monzogranite that locally, and regionally, truncates S 2 . Dominantly ca. 1780 Ma matrix monazite is interpreted to date post-S 2 garnet II and cordierite, which record ~5 kbar and 675 °C. These data indicate that the Committee Bay region experienced penetrative D 2 tectonometamorphism at ca. 18501820 Ma, with a subsequent static overprint. The absence of a ca. 1.85 Ga plutonic suite in the region suggests that low-pressure metamorphism was a response to thick-skinned crustal thickening initiated at ca. 1870 Ma. The new data highlight the importance of Paleoproterozoic reworking of the central Rae domain in the hinterland of the Trans-Hudson orogen. |
format |
Article in Journal/Newspaper |
author |
Carson, Chris J Berman, Robert G Stern, Richard A Sanborn-Barrie, Mary Skulski, Tom Sandeman, Hamish AI |
spellingShingle |
Carson, Chris J Berman, Robert G Stern, Richard A Sanborn-Barrie, Mary Skulski, Tom Sandeman, Hamish AI Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology |
author_facet |
Carson, Chris J Berman, Robert G Stern, Richard A Sanborn-Barrie, Mary Skulski, Tom Sandeman, Hamish AI |
author_sort |
Carson, Chris J |
title |
Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology |
title_short |
Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology |
title_full |
Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology |
title_fullStr |
Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology |
title_full_unstemmed |
Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology |
title_sort |
age constraints on the paleoproterozoic tectonometamorphic history of the committee bay region, western churchill province, canada: evidence from zircon and in situ monazite shrimp geochronology |
publisher |
Canadian Science Publishing |
publishDate |
2004 |
url |
http://dx.doi.org/10.1139/e04-054 http://www.nrcresearchpress.com/doi/pdf/10.1139/e04-054 |
long_lat |
ENVELOPE(-116.053,-116.053,62.834,62.834) ENVELOPE(-86.899,-86.899,68.268,68.268) |
geographic |
Canada Hudson Rae Committee Bay |
geographic_facet |
Canada Hudson Rae Committee Bay |
genre |
Committee Bay |
genre_facet |
Committee Bay |
op_source |
Canadian Journal of Earth Sciences volume 41, issue 9, page 1049-1076 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e04-054 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
41 |
container_issue |
9 |
container_start_page |
1049 |
op_container_end_page |
1076 |
_version_ |
1809905983579750400 |