The Otish Supergroup and Mistassini Group of north-central Quebec are two weakly metamorphosed sedimentary successions deposited during the middle Paleoproterozoic along the modern-day eastern margin of the Archean Superior craton. This study presents new uranium-lead (U-Pb) detrital zircon and shale rhenium-osmium (Re-Os) geochronological data for these two successions, as well as δ13Ccarb data from sedimentary carbonate rocks, which comprise the first such data for the Otish Supergroup. New geochronological data presented here demonstrate that the Mistassini Group was deposited between 2121 Ma and 1825 Ma and postdates the Otish Supergroup by at least ∼20 m.y. The δ13Ccarb data from the Otish Supergroup are strongly enriched, typically +7‰ to +12‰, and therefore consistent with deposition during the Lomagundi-Jatuli carbon isotope excursion (LJE), which is generally considered to have occurred during ca. 2220−2060 Ma. Within the basal ∼200 m of the Mistassini Group, δ13Ccarb values reach almost +8‰, before shifting to near 0‰ in the overlying ∼1800 m of strata, which indicates that it records the termination of the LJE. The Re-Os depositional age of 1825 ± 9 Ma for mudstones of the Kallio Formation, the uppermost formation in the Mistassini Group, provides a minimum constraint for deposition in the basin. Cumulatively, the new radiometric ages and stable isotope ratio data provide a basis for a new tectonostratigraphic reconstruction that closely links the Mistassini and Otish basins to the evolution of the Labrador Trough and other basins along the eastern and southern margins of the Superior craton.
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Research Article|
March 13, 2025
Early Publication
The Paleoproterozoic Otish and Mistassini basins of Quebec, Canada: A record of Superia supercraton breakup and the end of the Lomagundi-Jatuli carbon isotope excursion
Malcolm S.W. Hodgskiss;
Malcolm S.W. Hodgskiss
1
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom
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Maxwell A. Lechte;
Maxwell A. Lechte
2
Department of Earth and Planetary Sciences, McGill University, Montréal, Quebec H3A 0E8, Canada
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Robert H. Rainbird;
Robert H. Rainbird
3
Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada
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Margaret A. Whelan;
Margaret A. Whelan
2
Department of Earth and Planetary Sciences, McGill University, Montréal, Quebec H3A 0E8, Canada
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Robert A. Creaser;
Robert A. Creaser
4
Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
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William J. Davis;
William J. Davis
3
Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada
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Trond Slagstad;
Trond Slagstad
5
Geological Survey of Norway, 7491 Trondheim, Norway
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Eduardo T. Mansur;
Eduardo T. Mansur
5
Geological Survey of Norway, 7491 Trondheim, Norway
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Kalle Kirsimäe;
Kalle Kirsimäe
6
Department of Geology, University of Tartu, 50411 Tartu, Estonia
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Alex Kovalick;
Alex Kovalick
7
Department of Earth and Planetary Sciences, University of California, Riverside, California 92521, USA
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Andrey Bekker
Andrey Bekker
7
Department of Earth and Planetary Sciences, University of California, Riverside, California 92521, USA8
Department of Geology, University of Johannesburg, 2092 Johannesburg, South Africa
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Malcolm S.W. Hodgskiss
1
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom
Maxwell A. Lechte
2
Department of Earth and Planetary Sciences, McGill University, Montréal, Quebec H3A 0E8, Canada
Robert H. Rainbird
3
Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada
Margaret A. Whelan
2
Department of Earth and Planetary Sciences, McGill University, Montréal, Quebec H3A 0E8, Canada
Robert A. Creaser
4
Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
William J. Davis
3
Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada
Trond Slagstad
5
Geological Survey of Norway, 7491 Trondheim, Norway
Eduardo T. Mansur
5
Geological Survey of Norway, 7491 Trondheim, Norway
Kalle Kirsimäe
6
Department of Geology, University of Tartu, 50411 Tartu, Estonia
Alex Kovalick
7
Department of Earth and Planetary Sciences, University of California, Riverside, California 92521, USA
Andrey Bekker
7
Department of Earth and Planetary Sciences, University of California, Riverside, California 92521, USA8
Department of Geology, University of Johannesburg, 2092 Johannesburg, South Africa
Publisher: Geological Society of America
Received:
07 Aug 2024
Revision Received:
06 Dec 2024
Accepted:
21 Jan 2025
First Online:
14 Mar 2025
Online ISSN: 1943-2674
Print ISSN: 0016-7606
© 2025 Geological Society of America
GSA Bulletin (2025)
Article history
Received:
07 Aug 2024
Revision Received:
06 Dec 2024
Accepted:
21 Jan 2025
First Online:
14 Mar 2025
Citation
Malcolm S.W. Hodgskiss, Maxwell A. Lechte, Robert H. Rainbird, Margaret A. Whelan, Robert A. Creaser, William J. Davis, Trond Slagstad, Eduardo T. Mansur, Kalle Kirsimäe, Alex Kovalick, Andrey Bekker; The Paleoproterozoic Otish and Mistassini basins of Quebec, Canada: A record of Superia supercraton breakup and the end of the Lomagundi-Jatuli carbon isotope excursion. GSA Bulletin 2025; doi: https://doi.org/10.1130/B37948.1
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