Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland
Highly siderophile element (HSE) concentration and 187 Os/ 188 Os isotopic heterogeneity has been observed on various scales in the Earth's mantle. Interaction of residual mantle peridotite with infiltrating melts has been suggested to overprint primary bulk rock HSE signatures originating from...
Published in: | Geochimica et Cosmochimica Acta |
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Main Authors: | , , , , , , |
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Language: | English |
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2017
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ftuniaarhuspubl:oai:pure.atira.dk:publications/5fc192ce-50e7-48cb-9d10-b29083d722ba 2023-12-17T10:30:57+01:00 Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland van Acken, David Luguet, Ambre Pearson, D.G. Nowell, G.M. Fonseca, R.O.C. Nagel, Thorsten Schulz, T. 2017-04-15 https://pure.au.dk/portal/da/publications/mesoarchean-melting-and-neoarchean-to-paleoproterozoic-metasomatism-during-the-formation-of-the-cratonic-mantle-keel-beneath-west-greenland(5fc192ce-50e7-48cb-9d10-b29083d722ba).html https://doi.org/10.1016/j.gca.2017.01.006 eng eng https://pure.au.dk/portal/da/publications/mesoarchean-melting-and-neoarchean-to-paleoproterozoic-metasomatism-during-the-formation-of-the-cratonic-mantle-keel-beneath-west-greenland(5fc192ce-50e7-48cb-9d10-b29083d722ba).html info:eu-repo/semantics/closedAccess van Acken , D , Luguet , A , Pearson , D G , Nowell , G M , Fonseca , R O C , Nagel , T & Schulz , T 2017 , ' Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland ' , Geochimica et Cosmochimica Acta , vol. 203 , pp. 37-53 . https://doi.org/10.1016/j.gca.2017.01.006 Harzburgite Highly siderophile elements Mantle metasomatism Model ages Osmium isotopes article 2017 ftuniaarhuspubl https://doi.org/10.1016/j.gca.2017.01.006 2023-11-22T23:59:42Z Highly siderophile element (HSE) concentration and 187 Os/ 188 Os isotopic heterogeneity has been observed on various scales in the Earth's mantle. Interaction of residual mantle peridotite with infiltrating melts has been suggested to overprint primary bulk rock HSE signatures originating from partial melting, contributing to the heterogeneity seen in the global peridotite database. Here we present a detailed study of harzburgitic xenolith 474527 from the Kangerlussuaq suite, West Greenland, coupling the Re–Os isotope geochemistry with petrography of both base metal sulfides (BMS) and silicates to assess the impact of overprint induced by melt-rock reaction on the Re–Os isotope system. Garnet harzburgite sample 474527 shows considerable heterogeneity in the composition of its major phases, most notably olivine and Cr-rich garnet, suggesting formation through multiple stages of partial melting and subsequent metasomatic events. The major BMS phases show a fairly homogeneous pentlandite-rich composition typical for BMS formed via metasomatic reaction, whereas the 187 Os/ 188 Os compositions determined for 17 of these BMS are extremely heterogeneous ranging between 0.1037 and 0.1981. Analyses by LA-ICP-MS reveal at least two populations of BMS grains characterized by contrasting HSE patterns. One type of pattern is strongly enriched in the more compatible HSE Os, Ir, and Ru over the typically incompatible Pt, Pd, and Re, while the other type shows moderate enrichment of the more incompatible HSE and has overall lower compatible HSE/incompatible HSE composition. The small-scale heterogeneity observed in these BMS highlights the need for caution when utilizing the Re–Os system to date mantle events, as even depleted harzburgite samples such as 474527 are likely to have experienced a complex history of metasomatic overprinting, with uncertain effects on the HSE. Article in Journal/Newspaper Greenland Kangerlussuaq Aarhus University: Research Greenland Kangerlussuaq ENVELOPE(-55.633,-55.633,72.633,72.633) Geochimica et Cosmochimica Acta 203 37 53 |
institution |
Open Polar |
collection |
Aarhus University: Research |
op_collection_id |
ftuniaarhuspubl |
language |
English |
topic |
Harzburgite Highly siderophile elements Mantle metasomatism Model ages Osmium isotopes |
spellingShingle |
Harzburgite Highly siderophile elements Mantle metasomatism Model ages Osmium isotopes van Acken, David Luguet, Ambre Pearson, D.G. Nowell, G.M. Fonseca, R.O.C. Nagel, Thorsten Schulz, T. Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland |
topic_facet |
Harzburgite Highly siderophile elements Mantle metasomatism Model ages Osmium isotopes |
description |
Highly siderophile element (HSE) concentration and 187 Os/ 188 Os isotopic heterogeneity has been observed on various scales in the Earth's mantle. Interaction of residual mantle peridotite with infiltrating melts has been suggested to overprint primary bulk rock HSE signatures originating from partial melting, contributing to the heterogeneity seen in the global peridotite database. Here we present a detailed study of harzburgitic xenolith 474527 from the Kangerlussuaq suite, West Greenland, coupling the Re–Os isotope geochemistry with petrography of both base metal sulfides (BMS) and silicates to assess the impact of overprint induced by melt-rock reaction on the Re–Os isotope system. Garnet harzburgite sample 474527 shows considerable heterogeneity in the composition of its major phases, most notably olivine and Cr-rich garnet, suggesting formation through multiple stages of partial melting and subsequent metasomatic events. The major BMS phases show a fairly homogeneous pentlandite-rich composition typical for BMS formed via metasomatic reaction, whereas the 187 Os/ 188 Os compositions determined for 17 of these BMS are extremely heterogeneous ranging between 0.1037 and 0.1981. Analyses by LA-ICP-MS reveal at least two populations of BMS grains characterized by contrasting HSE patterns. One type of pattern is strongly enriched in the more compatible HSE Os, Ir, and Ru over the typically incompatible Pt, Pd, and Re, while the other type shows moderate enrichment of the more incompatible HSE and has overall lower compatible HSE/incompatible HSE composition. The small-scale heterogeneity observed in these BMS highlights the need for caution when utilizing the Re–Os system to date mantle events, as even depleted harzburgite samples such as 474527 are likely to have experienced a complex history of metasomatic overprinting, with uncertain effects on the HSE. |
format |
Article in Journal/Newspaper |
author |
van Acken, David Luguet, Ambre Pearson, D.G. Nowell, G.M. Fonseca, R.O.C. Nagel, Thorsten Schulz, T. |
author_facet |
van Acken, David Luguet, Ambre Pearson, D.G. Nowell, G.M. Fonseca, R.O.C. Nagel, Thorsten Schulz, T. |
author_sort |
van Acken, David |
title |
Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland |
title_short |
Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland |
title_full |
Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland |
title_fullStr |
Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland |
title_full_unstemmed |
Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland |
title_sort |
mesoarchean melting and neoarchean to paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath west greenland |
publishDate |
2017 |
url |
https://pure.au.dk/portal/da/publications/mesoarchean-melting-and-neoarchean-to-paleoproterozoic-metasomatism-during-the-formation-of-the-cratonic-mantle-keel-beneath-west-greenland(5fc192ce-50e7-48cb-9d10-b29083d722ba).html https://doi.org/10.1016/j.gca.2017.01.006 |
long_lat |
ENVELOPE(-55.633,-55.633,72.633,72.633) |
geographic |
Greenland Kangerlussuaq |
geographic_facet |
Greenland Kangerlussuaq |
genre |
Greenland Kangerlussuaq |
genre_facet |
Greenland Kangerlussuaq |
op_source |
van Acken , D , Luguet , A , Pearson , D G , Nowell , G M , Fonseca , R O C , Nagel , T & Schulz , T 2017 , ' Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland ' , Geochimica et Cosmochimica Acta , vol. 203 , pp. 37-53 . https://doi.org/10.1016/j.gca.2017.01.006 |
op_relation |
https://pure.au.dk/portal/da/publications/mesoarchean-melting-and-neoarchean-to-paleoproterozoic-metasomatism-during-the-formation-of-the-cratonic-mantle-keel-beneath-west-greenland(5fc192ce-50e7-48cb-9d10-b29083d722ba).html |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1016/j.gca.2017.01.006 |
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Geochimica et Cosmochimica Acta |
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