Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle
Molybdenum isotopes (reported as δ98Mo relative to NIST-3134) show resolvable isotope differences in igneous rocks with the continental crust being markedly heavier in isotope composition than mid-ocean ridge lavas, lunar basalts or the Earth's mantle. The tholeiitic differentiation series at t...
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ftunivbern:oai:boris.unibe.ch:152592 2023-08-20T04:07:03+02:00 Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle Nebel-Jacobsen, Yona Wille, Martin Ivanic, Tim Nebel, Oliver 2021 application/pdf https://boris.unibe.ch/152592/1/Nebel-Jacobsen_2021-PreRes.pdf https://boris.unibe.ch/152592/ eng eng Elsevier https://boris.unibe.ch/152592/ info:eu-repo/semantics/restrictedAccess Nebel-Jacobsen, Yona; Wille, Martin; Ivanic, Tim; Nebel, Oliver (2021). Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle. Precambrian research, 355, p. 106087. Elsevier 10.1016/j.precamres.2020.106087 <http://dx.doi.org/10.1016/j.precamres.2020.106087> 550 Earth sciences & geology info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion PeerReviewed 2021 ftunivbern https://doi.org/10.1016/j.precamres.2020.106087 2023-07-31T22:05:05Z Molybdenum isotopes (reported as δ98Mo relative to NIST-3134) show resolvable isotope differences in igneous rocks with the continental crust being markedly heavier in isotope composition than mid-ocean ridge lavas, lunar basalts or the Earth's mantle. The tholeiitic differentiation series at the intra-plate Hekla volcano (Iceland) shows no resolvable Mo isotope differences from basaltic to rhyolitic compositions. In contrast, convergent margin lavas show a transition from isotopically lighter mantle to heavy continental crust, suggesting that subduction processes drive continental crust towards heavier values. Archean komatiitic lavas, presumed probes of the Archean mantle, have Mo isotope values identical to modern depleted mantle, raising the questions if and how the Mo isotope crust-mantle disparity developed so early in Earth's history. Here we present new Mo isotope data for a set of cumulate rocks from the Upper Zone of late Archean (2.8 Ga) Windimurra Igneous Complex, a mafic/ultramafic layered intrusion. The intrusion is not subduction related and contains no apparent primary hydrous minerals. We tested the effect of crystal fractionation on Mo isotopes in relatively dry melt along a tholeiitic liquid line of descent by using the cumulate effect of normally anhydrous minerals in the layered intrusion. Near mono-mineralic olivine-pyroxene-rich, feldspar-rich and Fe-Ti-rich oxides show small variations (~0.15‰) in Mo isotope signatures. This is consequently to predominantly isotopically light Fe-Ti-oxide-rich and isotopically heavier feldspar-rich rocks, respectively. This is suggesting minor Mo isotope fractionation, even in dry, tholeiitic systems, which however, counterbalance each other and thus potentially remain undetected. On average, the Windimurra mantle source is indistinguishable, or slightly isotopically lighter than the Mo isotope signature of komatiites. This is reinforcing an isotopically light Mo isotope signature of Archean mantle sources of high-degree mantle melts and is extending these ... Article in Journal/Newspaper Hekla Iceland BORIS (Bern Open Repository and Information System, University of Bern) Precambrian Research 355 106087 |
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Open Polar |
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BORIS (Bern Open Repository and Information System, University of Bern) |
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ftunivbern |
language |
English |
topic |
550 Earth sciences & geology |
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550 Earth sciences & geology Nebel-Jacobsen, Yona Wille, Martin Ivanic, Tim Nebel, Oliver Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle |
topic_facet |
550 Earth sciences & geology |
description |
Molybdenum isotopes (reported as δ98Mo relative to NIST-3134) show resolvable isotope differences in igneous rocks with the continental crust being markedly heavier in isotope composition than mid-ocean ridge lavas, lunar basalts or the Earth's mantle. The tholeiitic differentiation series at the intra-plate Hekla volcano (Iceland) shows no resolvable Mo isotope differences from basaltic to rhyolitic compositions. In contrast, convergent margin lavas show a transition from isotopically lighter mantle to heavy continental crust, suggesting that subduction processes drive continental crust towards heavier values. Archean komatiitic lavas, presumed probes of the Archean mantle, have Mo isotope values identical to modern depleted mantle, raising the questions if and how the Mo isotope crust-mantle disparity developed so early in Earth's history. Here we present new Mo isotope data for a set of cumulate rocks from the Upper Zone of late Archean (2.8 Ga) Windimurra Igneous Complex, a mafic/ultramafic layered intrusion. The intrusion is not subduction related and contains no apparent primary hydrous minerals. We tested the effect of crystal fractionation on Mo isotopes in relatively dry melt along a tholeiitic liquid line of descent by using the cumulate effect of normally anhydrous minerals in the layered intrusion. Near mono-mineralic olivine-pyroxene-rich, feldspar-rich and Fe-Ti-rich oxides show small variations (~0.15‰) in Mo isotope signatures. This is consequently to predominantly isotopically light Fe-Ti-oxide-rich and isotopically heavier feldspar-rich rocks, respectively. This is suggesting minor Mo isotope fractionation, even in dry, tholeiitic systems, which however, counterbalance each other and thus potentially remain undetected. On average, the Windimurra mantle source is indistinguishable, or slightly isotopically lighter than the Mo isotope signature of komatiites. This is reinforcing an isotopically light Mo isotope signature of Archean mantle sources of high-degree mantle melts and is extending these ... |
format |
Article in Journal/Newspaper |
author |
Nebel-Jacobsen, Yona Wille, Martin Ivanic, Tim Nebel, Oliver |
author_facet |
Nebel-Jacobsen, Yona Wille, Martin Ivanic, Tim Nebel, Oliver |
author_sort |
Nebel-Jacobsen, Yona |
title |
Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle |
title_short |
Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle |
title_full |
Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle |
title_fullStr |
Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle |
title_full_unstemmed |
Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle |
title_sort |
molybdenum isotope systematics in cumulate rock of the 2.8 windimurra layered intrusion: a test for igneous differentiation and the composition of the archean mantle |
publisher |
Elsevier |
publishDate |
2021 |
url |
https://boris.unibe.ch/152592/1/Nebel-Jacobsen_2021-PreRes.pdf https://boris.unibe.ch/152592/ |
genre |
Hekla Iceland |
genre_facet |
Hekla Iceland |
op_source |
Nebel-Jacobsen, Yona; Wille, Martin; Ivanic, Tim; Nebel, Oliver (2021). Molybdenum isotope systematics in cumulate rock of the 2.8 Windimurra layered intrusion: A test for igneous differentiation and the composition of the Archean mantle. Precambrian research, 355, p. 106087. Elsevier 10.1016/j.precamres.2020.106087 <http://dx.doi.org/10.1016/j.precamres.2020.106087> |
op_relation |
https://boris.unibe.ch/152592/ |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.precamres.2020.106087 |
container_title |
Precambrian Research |
container_volume |
355 |
container_start_page |
106087 |
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1774718469054398464 |