A Contiguous Taltson‐Thelon Margin Revisited

Abstract The amalgamation of Laurentia was initiated along the western margin of the Rae craton. However, the tectonic setting that generated magmatic rocks along this margin has long been debated, with the Thelon tectonic zone in the north having formed in an arc setting, and the Taltson magmatic z...

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Main Authors: J. A. Cutts, B. V. Dyck, M. G. Perrot, J. H. F. L. Davies, A. M. Osinchuk, D. Šilerová, R. A. Stern, M. Chiaradia, R. Canam
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Language:English
Published: Wiley 2024-07-01
Series:Geochemistry, Geophysics, Geosystems
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Online Access:https://doi.org/10.1029/2024GC011527
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author J. A. Cutts
B. V. Dyck
M. G. Perrot
J. H. F. L. Davies
A. M. Osinchuk
D. Šilerová
R. A. Stern
M. Chiaradia
R. Canam
author_facet J. A. Cutts
B. V. Dyck
M. G. Perrot
J. H. F. L. Davies
A. M. Osinchuk
D. Šilerová
R. A. Stern
M. Chiaradia
R. Canam
author_sort J. A. Cutts
collection DOAJ
description Abstract The amalgamation of Laurentia was initiated along the western margin of the Rae craton. However, the tectonic setting that generated magmatic rocks along this margin has long been debated, with the Thelon tectonic zone in the north having formed in an arc setting, and the Taltson magmatic zone in the south variably attributed to either continental arc or intracratonic magmatism. The magmatic rocks of the Great Slave Lake shear zone (GSLsz) lie between these two tectonic belts and, thus, may be critical to the interpretation of the evolution of the western Rae margin. To understand the origin of the rocks in the GSLsz, we have applied U‐Pb geochronology, trace‐element geochemistry, and O and Hf isotope analyses to zircons from a suite of samples that transect the La Loche River fault (LRf)—a major structure that bisects the GSLsz. Samples collected to the north of the LRf are Neoarchean in age, have mantle‐like δ18O (4.7–5.8‰) and chondritic to juvenile εHf values (0–4.5), whereas those to the south are exclusively Paleoproterozoic in age and have more elevated δ18O (6.3–7‰) and much more evolved εHf values (−12 to −6); these results indicate that the LRf marks a crustal‐scale suture between the Slave craton and the Taltson magmatic zone. Our isotopic data, together with other regional constraints from the area, are most consistent with the Taltson magmatic zone having formed in a continental arc setting emplaced into ca. 2.3 Ga juvenile basement crust.
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spelling doaj-art-7b86b5e2af7c4a55a122095b70d7ccee2025-08-20T03:49:32ZengWileyGeochemistry, Geophysics, Geosystems1525-20272024-07-01257n/an/a10.1029/2024GC011527A Contiguous Taltson‐Thelon Margin RevisitedJ. A. Cutts0B. V. Dyck1M. G. Perrot2J. H. F. L. Davies3A. M. Osinchuk4D. Šilerová5R. A. Stern6M. Chiaradia7R. Canam8Natural Resources Canada Geological Survey of Canada Ottawa ON CanadaDepartment of Earth, Environmental and Geographical Sciences University of British Columbia Kelowna BC CanadaDépartement des Sciences de la Terre et de l'atmosphère/Geotop Université du Québec à Montréal (UQAM) Montréal QC CanadaDépartement des Sciences de la Terre et de l'atmosphère/Geotop Université du Québec à Montréal (UQAM) Montréal QC CanadaDepartment of Earth, Environmental and Geographical Sciences University of British Columbia Kelowna BC CanadaDepartment of Geology Saint Mary's University Halifax NS CanadaDepartment of Earth and Atmospheric Sciences Canadian Center for Isotopic Microanalysis (CCIM) University of Alberta Edmonton AB CanadaDépartement de Science de la Terre et de l'environnement Université de Genève Geneva SwitzerlandNorthwest Territories Geological Survey Yellowknife NT CanadaAbstract The amalgamation of Laurentia was initiated along the western margin of the Rae craton. However, the tectonic setting that generated magmatic rocks along this margin has long been debated, with the Thelon tectonic zone in the north having formed in an arc setting, and the Taltson magmatic zone in the south variably attributed to either continental arc or intracratonic magmatism. The magmatic rocks of the Great Slave Lake shear zone (GSLsz) lie between these two tectonic belts and, thus, may be critical to the interpretation of the evolution of the western Rae margin. To understand the origin of the rocks in the GSLsz, we have applied U‐Pb geochronology, trace‐element geochemistry, and O and Hf isotope analyses to zircons from a suite of samples that transect the La Loche River fault (LRf)—a major structure that bisects the GSLsz. Samples collected to the north of the LRf are Neoarchean in age, have mantle‐like δ18O (4.7–5.8‰) and chondritic to juvenile εHf values (0–4.5), whereas those to the south are exclusively Paleoproterozoic in age and have more elevated δ18O (6.3–7‰) and much more evolved εHf values (−12 to −6); these results indicate that the LRf marks a crustal‐scale suture between the Slave craton and the Taltson magmatic zone. Our isotopic data, together with other regional constraints from the area, are most consistent with the Taltson magmatic zone having formed in a continental arc setting emplaced into ca. 2.3 Ga juvenile basement crust.https://doi.org/10.1029/2024GC011527oxygen isotopehafnium isotopezirconRae cratonThelon tectonic zoneTaltson magmatic zone
spellingShingle J. A. Cutts
B. V. Dyck
M. G. Perrot
J. H. F. L. Davies
A. M. Osinchuk
D. Šilerová
R. A. Stern
M. Chiaradia
R. Canam
A Contiguous Taltson‐Thelon Margin Revisited
Geochemistry, Geophysics, Geosystems
oxygen isotope
hafnium isotope
zircon
Rae craton
Thelon tectonic zone
Taltson magmatic zone
title A Contiguous Taltson‐Thelon Margin Revisited
title_full A Contiguous Taltson‐Thelon Margin Revisited
title_fullStr A Contiguous Taltson‐Thelon Margin Revisited
title_full_unstemmed A Contiguous Taltson‐Thelon Margin Revisited
title_short A Contiguous Taltson‐Thelon Margin Revisited
title_sort contiguous taltson thelon margin revisited
topic oxygen isotope
hafnium isotope
zircon
Rae craton
Thelon tectonic zone
Taltson magmatic zone
url https://doi.org/10.1029/2024GC011527
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