Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence
Northwest Territories Geoscience Office, P.O. Box 1500, Yellowknife, NT, Canada X1A 2R3 The Abitibi subprovince is widely regarded as a classic example of Neoarchean continental crust formed in an ensimatic setting. However, sialic crust as old as 2.93 Ga occurs in the adjacent Wawa subprovince, and...
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ftmacquarieunicr:oai:https://researchers.mq.edu.au:publications/e3396716-a41b-460f-9e8b-f14aaef24c07 2024-06-02T08:12:20+00:00 Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence Ketchum, John W F Ayer, John A. Van Breemen, Otto Pearson, Norman J. Becker, Jens K. 2008-09 https://researchers.mq.edu.au/en/publications/e3396716-a41b-460f-9e8b-f14aaef24c07 https://doi.org/10.2113/gsecongeo.103.6.1151 http://www.scopus.com/inward/record.url?scp=60349123149&partnerID=8YFLogxK eng eng info:eu-repo/semantics/restrictedAccess Ketchum , J W F , Ayer , J A , Van Breemen , O , Pearson , N J & Becker , J K 2008 , ' Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence ' , Economic Geology , vol. 103 , no. 6 , pp. 1151-1184 . https://doi.org/10.2113/gsecongeo.103.6.1151 article 2008 ftmacquarieunicr https://doi.org/10.2113/gsecongeo.103.6.1151 2024-05-07T03:23:29Z Northwest Territories Geoscience Office, P.O. Box 1500, Yellowknife, NT, Canada X1A 2R3 The Abitibi subprovince is widely regarded as a classic example of Neoarchean continental crust formed in an ensimatic setting. However, sialic crust as old as 2.93 Ga occurs in the adjacent Wawa subprovince, and the two subprovinces are thought to have formed a contiguous block since the initiation of Abitibi magmatic activity at 2.75 Ga. A detailed geochemical, U-Pb geochronological, and Nd-Hf isotope study of plutonic and volcanic rocks from the southwestern Abitibi provides evidence for the involvement of older crust during magma genesis near the Abitibi-Wawa boundary (Kapuskasing structural zone). Inherited zircons dated at ca. 2.85 Ga occur both in 2747 Ma tonalité and 2700 Ma granodiorite of the Rice Lake batholith, part of the larger Kenogamissi plutonic complex. Igneous zircons from this batholith display large intrasample variations in 176 Hf/ 177 Hf, which we attribute to mixing of magmas derived from mantle ± juvenile crust and older crustal sources. Nd isotope data for felsic volcanic and plutonic rocks in this region indicate a dominantly juvenile source; however, two older felsic volcanic units (2739 and 2729 Ma) show Nd isotope evidence of significant crustal contamination. Posttectonic plutonic units that were emplaced at 2676 and 2662 Ma also contain inherited zircons, but none are older than 2.76 Ga. In contrast, tonalitic units dated at 2744 and 2715 Ma from the Round Lake plutonic complex, located 150 km east of the Kapuskasing structural zone, lack zircon inheritance and display less intrasample Hf isotope variability in zircons. Our data suggest that the influence of older sialic crust during Abitibi volcanic and plutonic activity is restricted both in space and time. Similar evidence for an older crustal influence occurs elsewhere in the southwestern Abitibi near the Kapuskasing structural zone. The data collectively suggest that an approximately 75-km-wide belt of Abitibi crust adjacent to this ... Article in Journal/Newspaper Northwest Territories Yellowknife Macquarie University Research Portal Canada Northwest Territories Rice Lake ENVELOPE(-103.767,-103.767,56.850,56.850) Round Lake ENVELOPE(142.665,142.665,-66.993,-66.993) Yellowknife Economic Geology 103 6 1151 1184 |
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Northwest Territories Geoscience Office, P.O. Box 1500, Yellowknife, NT, Canada X1A 2R3 The Abitibi subprovince is widely regarded as a classic example of Neoarchean continental crust formed in an ensimatic setting. However, sialic crust as old as 2.93 Ga occurs in the adjacent Wawa subprovince, and the two subprovinces are thought to have formed a contiguous block since the initiation of Abitibi magmatic activity at 2.75 Ga. A detailed geochemical, U-Pb geochronological, and Nd-Hf isotope study of plutonic and volcanic rocks from the southwestern Abitibi provides evidence for the involvement of older crust during magma genesis near the Abitibi-Wawa boundary (Kapuskasing structural zone). Inherited zircons dated at ca. 2.85 Ga occur both in 2747 Ma tonalité and 2700 Ma granodiorite of the Rice Lake batholith, part of the larger Kenogamissi plutonic complex. Igneous zircons from this batholith display large intrasample variations in 176 Hf/ 177 Hf, which we attribute to mixing of magmas derived from mantle ± juvenile crust and older crustal sources. Nd isotope data for felsic volcanic and plutonic rocks in this region indicate a dominantly juvenile source; however, two older felsic volcanic units (2739 and 2729 Ma) show Nd isotope evidence of significant crustal contamination. Posttectonic plutonic units that were emplaced at 2676 and 2662 Ma also contain inherited zircons, but none are older than 2.76 Ga. In contrast, tonalitic units dated at 2744 and 2715 Ma from the Round Lake plutonic complex, located 150 km east of the Kapuskasing structural zone, lack zircon inheritance and display less intrasample Hf isotope variability in zircons. Our data suggest that the influence of older sialic crust during Abitibi volcanic and plutonic activity is restricted both in space and time. Similar evidence for an older crustal influence occurs elsewhere in the southwestern Abitibi near the Kapuskasing structural zone. The data collectively suggest that an approximately 75-km-wide belt of Abitibi crust adjacent to this ... |
format |
Article in Journal/Newspaper |
author |
Ketchum, John W F Ayer, John A. Van Breemen, Otto Pearson, Norman J. Becker, Jens K. |
spellingShingle |
Ketchum, John W F Ayer, John A. Van Breemen, Otto Pearson, Norman J. Becker, Jens K. Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence |
author_facet |
Ketchum, John W F Ayer, John A. Van Breemen, Otto Pearson, Norman J. Becker, Jens K. |
author_sort |
Ketchum, John W F |
title |
Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence |
title_short |
Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence |
title_full |
Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence |
title_fullStr |
Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence |
title_full_unstemmed |
Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence |
title_sort |
pericontinental crustal growth of the southwestern abitibi subprovince, canada - u-pb, hf, and nd isotope evidence |
publishDate |
2008 |
url |
https://researchers.mq.edu.au/en/publications/e3396716-a41b-460f-9e8b-f14aaef24c07 https://doi.org/10.2113/gsecongeo.103.6.1151 http://www.scopus.com/inward/record.url?scp=60349123149&partnerID=8YFLogxK |
long_lat |
ENVELOPE(-103.767,-103.767,56.850,56.850) ENVELOPE(142.665,142.665,-66.993,-66.993) |
geographic |
Canada Northwest Territories Rice Lake Round Lake Yellowknife |
geographic_facet |
Canada Northwest Territories Rice Lake Round Lake Yellowknife |
genre |
Northwest Territories Yellowknife |
genre_facet |
Northwest Territories Yellowknife |
op_source |
Ketchum , J W F , Ayer , J A , Van Breemen , O , Pearson , N J & Becker , J K 2008 , ' Pericontinental crustal growth of the southwestern abitibi subprovince, Canada - U-Pb, Hf, and Nd isotope evidence ' , Economic Geology , vol. 103 , no. 6 , pp. 1151-1184 . https://doi.org/10.2113/gsecongeo.103.6.1151 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.2113/gsecongeo.103.6.1151 |
container_title |
Economic Geology |
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103 |
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6 |
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1151 |
op_container_end_page |
1184 |
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