Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean
Calculations of the energetics of terrestrial accretion indicate that the Earth was extensively molten in its early history. Examination of early Archaean rocks from West Greenland (3.6-3.8 Gyr old) using short-lived 146 Sm- 142 Nd chronometry indicates that an episode of mantle differentiation took...
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ftmacquarieunicr:oai:https://researchers.mq.edu.au:publications/9a5be14e-76b5-4c14-bda3-c38111112d5b 2024-06-23T07:53:17+00:00 Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean Caro, Guillaume Bourdon, Bernard Wood, Bernard J. Corgne, Alexandre 2005-07-14 https://researchers.mq.edu.au/en/publications/9a5be14e-76b5-4c14-bda3-c38111112d5b https://doi.org/10.1038/nature03827 http://www.scopus.com/inward/record.url?scp=22544433132&partnerID=8YFLogxK eng eng info:eu-repo/semantics/closedAccess Caro , G , Bourdon , B , Wood , B J & Corgne , A 2005 , ' Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean ' , Nature , vol. 436 , no. 7048 , pp. 246-249 . https://doi.org/10.1038/nature03827 article 2005 ftmacquarieunicr https://doi.org/10.1038/nature03827 2024-06-12T23:47:21Z Calculations of the energetics of terrestrial accretion indicate that the Earth was extensively molten in its early history. Examination of early Archaean rocks from West Greenland (3.6-3.8 Gyr old) using short-lived 146 Sm- 142 Nd chronometry indicates that an episode of mantle differentiation took place close to the end of accretion (4.46 ± 0.11 Gyr ago). This has produced a chemically depleted mantle with an Sm/Nd ratio higher than the chondritic value. In contrast, application of 176 Lu- 176 Hf systematics to 3.6-3.8-Gyr-old zircons from West Greenland indicates derivation from a mantle source with a chondritic Lu/Hf ratio. Although an early Sm/Nd fractionation could be explained by basaltic crust formation, magma ocean crystallization or formation of continental crust, the absence of coeval Lu/Hf fractionation is in sharp contrast with the well-known covariant behaviour of Sm/Nd and Lu/Hf ratios in crustal formation processes. Here we show using mineral-melt partitioning data for high-pressure mantle minerals that the observed Nd and Hf signatures could have been produced by segregation of melt from a crystallizing magma ocean at upper-mantle pressures early in Earth's history. This residual melt would have risen buoyantly and ultimately formed the earliest terrestrial protocrust. Article in Journal/Newspaper Greenland Macquarie University Research Portal Greenland Nature 436 7048 246 249 |
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English |
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Calculations of the energetics of terrestrial accretion indicate that the Earth was extensively molten in its early history. Examination of early Archaean rocks from West Greenland (3.6-3.8 Gyr old) using short-lived 146 Sm- 142 Nd chronometry indicates that an episode of mantle differentiation took place close to the end of accretion (4.46 ± 0.11 Gyr ago). This has produced a chemically depleted mantle with an Sm/Nd ratio higher than the chondritic value. In contrast, application of 176 Lu- 176 Hf systematics to 3.6-3.8-Gyr-old zircons from West Greenland indicates derivation from a mantle source with a chondritic Lu/Hf ratio. Although an early Sm/Nd fractionation could be explained by basaltic crust formation, magma ocean crystallization or formation of continental crust, the absence of coeval Lu/Hf fractionation is in sharp contrast with the well-known covariant behaviour of Sm/Nd and Lu/Hf ratios in crustal formation processes. Here we show using mineral-melt partitioning data for high-pressure mantle minerals that the observed Nd and Hf signatures could have been produced by segregation of melt from a crystallizing magma ocean at upper-mantle pressures early in Earth's history. This residual melt would have risen buoyantly and ultimately formed the earliest terrestrial protocrust. |
format |
Article in Journal/Newspaper |
author |
Caro, Guillaume Bourdon, Bernard Wood, Bernard J. Corgne, Alexandre |
spellingShingle |
Caro, Guillaume Bourdon, Bernard Wood, Bernard J. Corgne, Alexandre Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean |
author_facet |
Caro, Guillaume Bourdon, Bernard Wood, Bernard J. Corgne, Alexandre |
author_sort |
Caro, Guillaume |
title |
Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean |
title_short |
Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean |
title_full |
Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean |
title_fullStr |
Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean |
title_full_unstemmed |
Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean |
title_sort |
trace-element fractionation in hadean mantle generated by melt segregation from a magma ocean |
publishDate |
2005 |
url |
https://researchers.mq.edu.au/en/publications/9a5be14e-76b5-4c14-bda3-c38111112d5b https://doi.org/10.1038/nature03827 http://www.scopus.com/inward/record.url?scp=22544433132&partnerID=8YFLogxK |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Caro , G , Bourdon , B , Wood , B J & Corgne , A 2005 , ' Trace-element fractionation in Hadean mantle generated by melt segregation from a magma ocean ' , Nature , vol. 436 , no. 7048 , pp. 246-249 . https://doi.org/10.1038/nature03827 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1038/nature03827 |
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Nature |
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436 |
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7048 |
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246 |
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249 |
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1802644867250126848 |