Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust
Primordial silicate differentiation controlled the composition of Earth's oldest crust. Inherited 142Nd anomalies in Archean rocks are vestiges of the mantle-crust differentiation before ca. 4300 Ma. Here we report new whole-rock 147,146Sm-143,142Nd data for the Acasta Gneiss Complex (AGC; Nort...
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ftucambridgeesc:oai:eprints.esc.cam.ac.uk:3126 2023-05-15T16:30:04+02:00 Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust Roth, Antoine S. G. Bourdon, Bernard Mojzsis, Stephen J. Rudge, John F. Guitreau, Martin Blichert-Toft, Janne 2014-06-10 image text http://eprints.esc.cam.ac.uk/3126/ http://eprints.esc.cam.ac.uk/3126/1/ggge20474-fig-0001.png http://eprints.esc.cam.ac.uk/3126/2/Roth%20et%20al.%20-%202014%20-%20Combined147,146Sm-143,142Nd%20constraints%20on%20the%20lon.pdf http://eprints.esc.cam.ac.uk/3126/3/ggge20474-sup-0001-suppinfo01.docx http://eprints.esc.cam.ac.uk/3126/4/ggge20474-sup-0002-suppinfotabS1.xlsx http://eprints.esc.cam.ac.uk/3126/5/ggge20474-sup-0003-suppinfotabS2.docx http://eprints.esc.cam.ac.uk/3126/6/ggge20474-sup-0004-suppinfotabS3.xlsx http://eprints.esc.cam.ac.uk/3126/7/ggge20474-sup-0005-suppinfotabS4.xlsx http://onlinelibrary.wiley.com/doi/10.1002/2014GC005313/abstract https://doi.org/10.1002/2014GC005313 en eng AGU http://eprints.esc.cam.ac.uk/3126/1/ggge20474-fig-0001.png http://eprints.esc.cam.ac.uk/3126/2/Roth%20et%20al.%20-%202014%20-%20Combined147,146Sm-143,142Nd%20constraints%20on%20the%20lon.pdf http://eprints.esc.cam.ac.uk/3126/3/ggge20474-sup-0001-suppinfo01.docx http://eprints.esc.cam.ac.uk/3126/4/ggge20474-sup-0002-suppinfotabS1.xlsx http://eprints.esc.cam.ac.uk/3126/5/ggge20474-sup-0003-suppinfotabS2.docx http://eprints.esc.cam.ac.uk/3126/6/ggge20474-sup-0004-suppinfotabS3.xlsx http://eprints.esc.cam.ac.uk/3126/7/ggge20474-sup-0005-suppinfotabS4.xlsx Roth, Antoine S. G. and Bourdon, Bernard and Mojzsis, Stephen J. and Rudge, John F. and Guitreau, Martin and Blichert-Toft, Janne (2014) Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust. Geochemistry, Geophysics, Geosystems, 15 (6). pp. 2329-2345. DOI https://doi.org/10.1002/2014GC005313 <https://doi.org/10.1002/2014GC005313> 02 - Geodynamics Geophysics and Tectonics Article PeerReviewed 2014 ftucambridgeesc https://doi.org/10.1002/2014GC005313 2020-08-27T18:09:33Z Primordial silicate differentiation controlled the composition of Earth's oldest crust. Inherited 142Nd anomalies in Archean rocks are vestiges of the mantle-crust differentiation before ca. 4300 Ma. Here we report new whole-rock 147,146Sm-143,142Nd data for the Acasta Gneiss Complex (AGC; Northwest Territories, Canada). Our 147Sm-143Nd data combined with literature data define an age of 3371 ± 141 Ma (2 SD) and yield an initial ε143Nd of −5.6 ± 2.1. These results are at odds with the Acasta zircon U-Pb record, which comprises emplacement ages of 3920–3960 Ma. Ten of our thirteen samples show 142Nd deficits of −9.6 ± 4.8 ppm (2 SD) relative to the modern Earth. The discrepancy between 142Nd anomalies and a mid-Archean 147Sm-143Nd age can be reconciled with Nd isotope reequilibration of the AGC during metamorphic perturbations at ca. 3400 Ma. A model age of ca. 4310 Ma is derived for the early enrichment of the Acasta source. Two compositional end-members can be identified: a felsic component with 142Nd/144Nd identical to the modern Earth and a mafic component with 142Nd/144Nd as low as −14.1 ppm. The ca. 4310 Ma AGC source is ∼200 Myr younger than those estimated for Nuvvuagittuq (northern Québec) and Isua (Itsaq Gneiss Complex, West Greenland). The AGC does not have the same decoupled Nd-Hf isotope systematics as these other two terranes, which have been attributed to the crystallization of an early magma ocean. The Acasta signature rather is ascribed to the formation of Hadean crust that was preserved for several hundred Myr. Its longevity can be linked to 142Nd evolution in the mantle and does not require slow mantle stirring times nor modification of its convective mode. Article in Journal/Newspaper Greenland Northwest Territories University of Cambridge, Department of Earth Sciences: ESC Publications Canada Greenland Northwest Territories Geochemistry, Geophysics, Geosystems 15 6 2329 2345 |
institution |
Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
02 - Geodynamics Geophysics and Tectonics |
spellingShingle |
02 - Geodynamics Geophysics and Tectonics Roth, Antoine S. G. Bourdon, Bernard Mojzsis, Stephen J. Rudge, John F. Guitreau, Martin Blichert-Toft, Janne Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust |
topic_facet |
02 - Geodynamics Geophysics and Tectonics |
description |
Primordial silicate differentiation controlled the composition of Earth's oldest crust. Inherited 142Nd anomalies in Archean rocks are vestiges of the mantle-crust differentiation before ca. 4300 Ma. Here we report new whole-rock 147,146Sm-143,142Nd data for the Acasta Gneiss Complex (AGC; Northwest Territories, Canada). Our 147Sm-143Nd data combined with literature data define an age of 3371 ± 141 Ma (2 SD) and yield an initial ε143Nd of −5.6 ± 2.1. These results are at odds with the Acasta zircon U-Pb record, which comprises emplacement ages of 3920–3960 Ma. Ten of our thirteen samples show 142Nd deficits of −9.6 ± 4.8 ppm (2 SD) relative to the modern Earth. The discrepancy between 142Nd anomalies and a mid-Archean 147Sm-143Nd age can be reconciled with Nd isotope reequilibration of the AGC during metamorphic perturbations at ca. 3400 Ma. A model age of ca. 4310 Ma is derived for the early enrichment of the Acasta source. Two compositional end-members can be identified: a felsic component with 142Nd/144Nd identical to the modern Earth and a mafic component with 142Nd/144Nd as low as −14.1 ppm. The ca. 4310 Ma AGC source is ∼200 Myr younger than those estimated for Nuvvuagittuq (northern Québec) and Isua (Itsaq Gneiss Complex, West Greenland). The AGC does not have the same decoupled Nd-Hf isotope systematics as these other two terranes, which have been attributed to the crystallization of an early magma ocean. The Acasta signature rather is ascribed to the formation of Hadean crust that was preserved for several hundred Myr. Its longevity can be linked to 142Nd evolution in the mantle and does not require slow mantle stirring times nor modification of its convective mode. |
format |
Article in Journal/Newspaper |
author |
Roth, Antoine S. G. Bourdon, Bernard Mojzsis, Stephen J. Rudge, John F. Guitreau, Martin Blichert-Toft, Janne |
author_facet |
Roth, Antoine S. G. Bourdon, Bernard Mojzsis, Stephen J. Rudge, John F. Guitreau, Martin Blichert-Toft, Janne |
author_sort |
Roth, Antoine S. G. |
title |
Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust |
title_short |
Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust |
title_full |
Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust |
title_fullStr |
Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust |
title_full_unstemmed |
Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust |
title_sort |
combined147,146sm-143,142nd constraints on the longevity and residence time of early terrestrial crust |
publisher |
AGU |
publishDate |
2014 |
url |
http://eprints.esc.cam.ac.uk/3126/ http://eprints.esc.cam.ac.uk/3126/1/ggge20474-fig-0001.png http://eprints.esc.cam.ac.uk/3126/2/Roth%20et%20al.%20-%202014%20-%20Combined147,146Sm-143,142Nd%20constraints%20on%20the%20lon.pdf http://eprints.esc.cam.ac.uk/3126/3/ggge20474-sup-0001-suppinfo01.docx http://eprints.esc.cam.ac.uk/3126/4/ggge20474-sup-0002-suppinfotabS1.xlsx http://eprints.esc.cam.ac.uk/3126/5/ggge20474-sup-0003-suppinfotabS2.docx http://eprints.esc.cam.ac.uk/3126/6/ggge20474-sup-0004-suppinfotabS3.xlsx http://eprints.esc.cam.ac.uk/3126/7/ggge20474-sup-0005-suppinfotabS4.xlsx http://onlinelibrary.wiley.com/doi/10.1002/2014GC005313/abstract https://doi.org/10.1002/2014GC005313 |
geographic |
Canada Greenland Northwest Territories |
geographic_facet |
Canada Greenland Northwest Territories |
genre |
Greenland Northwest Territories |
genre_facet |
Greenland Northwest Territories |
op_relation |
http://eprints.esc.cam.ac.uk/3126/1/ggge20474-fig-0001.png http://eprints.esc.cam.ac.uk/3126/2/Roth%20et%20al.%20-%202014%20-%20Combined147,146Sm-143,142Nd%20constraints%20on%20the%20lon.pdf http://eprints.esc.cam.ac.uk/3126/3/ggge20474-sup-0001-suppinfo01.docx http://eprints.esc.cam.ac.uk/3126/4/ggge20474-sup-0002-suppinfotabS1.xlsx http://eprints.esc.cam.ac.uk/3126/5/ggge20474-sup-0003-suppinfotabS2.docx http://eprints.esc.cam.ac.uk/3126/6/ggge20474-sup-0004-suppinfotabS3.xlsx http://eprints.esc.cam.ac.uk/3126/7/ggge20474-sup-0005-suppinfotabS4.xlsx Roth, Antoine S. G. and Bourdon, Bernard and Mojzsis, Stephen J. and Rudge, John F. and Guitreau, Martin and Blichert-Toft, Janne (2014) Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust. Geochemistry, Geophysics, Geosystems, 15 (6). pp. 2329-2345. DOI https://doi.org/10.1002/2014GC005313 <https://doi.org/10.1002/2014GC005313> |
op_doi |
https://doi.org/10.1002/2014GC005313 |
container_title |
Geochemistry, Geophysics, Geosystems |
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15 |
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6 |
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2329 |
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2345 |
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