Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements
Measurements of 142Nd isotope signatures in Archean rocks are a powerful tool to investigate the earliest silicate differentiation events on Earth. Here, we introduce a new analytical protocol that allows high precision radiogenic and mass-independent Nd isotope measurements by MC-ICP-MS. To validat...
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Online Access: | https://refubium.fu-berlin.de/handle/fub188/37969 https://doi.org/10.17169/refubium-37685 https://doi.org/10.1016/j.chemgeo.2022.121141 |
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ftfuberlin:oai:refubium.fu-berlin.de:fub188/37969 2023-05-15T13:21:43+02:00 Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements Hasenstab-Dübeler, Eric Tusch, Jonas Hoffmann, J. Elis Fischer-Gödde, Mario Szilas, Kristoffer Münker, Carsten 2022 20 Seiten application/pdf https://refubium.fu-berlin.de/handle/fub188/37969 https://doi.org/10.17169/refubium-37685 https://doi.org/10.1016/j.chemgeo.2022.121141 eng eng https://refubium.fu-berlin.de/handle/fub188/37969 http://dx.doi.org/10.17169/refubium-37685 doi:10.1016/j.chemgeo.2022.121141 https://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Hadean differentiation Archean Mantle heterogeneity Isua supracrustal belt: 142Nd MC ICP-MS ddc:550 doc-type:article 2022 ftfuberlin https://doi.org/10.17169/refubium-37685 https://doi.org/10.1016/j.chemgeo.2022.121141 2023-02-19T23:24:17Z Measurements of 142Nd isotope signatures in Archean rocks are a powerful tool to investigate the earliest silicate differentiation events on Earth. Here, we introduce a new analytical protocol that allows high precision radiogenic and mass-independent Nd isotope measurements by MC-ICP-MS. To validate our method, we have measured well-characterized ∼3.72 to ∼3.8 Ga samples from the Eoarchean Itsaq Gneiss Complex and associated supracrustal belts, as well as Mesoarchean greenstones and a Proterozoic dike in SW Greenland, including lithostratigraphic units that were previously analyzed for 142-143Nd isotope systematics, by both TIMS and MC-ICP-MS. Our μ142Nd values for ∼3.72 to ∼3.8 Ga rocks from the Isua region range from +9.2 ± 2.6 to +13.2 ± 1.1 ppm and are in good agreement with previous studies. Using coupled 142,143Nd/144Nd isotope systematics from our data for ∼3.8 Ga mafic-ultramafic successions from the Isua region, we can confirm previous age constraints on the earliest silicate differentiation events with differentiation age of 4.390−0.060+0.045 Ga. Moreover, we can resolve a statistically significant decrease of 142Nd/144Nd isotope compositions in the ambient mantle of SW Greenland that already started to commence by Eoarchean time, between ∼3.8 Ga (μ142Nd = +13.0 ± 1.1) and ∼ 3.72 Ga (μ142Nd = +9.8 ± 1.0). Even lower but homogeneous μ142Nd values of +3.8 ± 1.1 are found in ∼3.4 Ga mantle-derived rocks from the Ameralik dike swarms. Our study reveals that ε143Nd(i) and εHf(i) values of Isua rocks scatter more than it would be expected from a single stage differentiation event as implied from nearly uniform μ142Nd values, suggesting that the previously described decoupling of Hf and Nd isotopes is not a primordial magma ocean signature. Instead, we conclude that some of second stage processes like younger mantle depletion events or recycling of subducted material affected the 147Smsingle bond143Nd isotope systematics. The preservation of pristine whole-rock isochrons largely rules out a significant ... Article in Journal/Newspaper Ameralik Greenland Freie Universität Berlin: Refubium (FU Berlin) Ameralik ENVELOPE(-51.000,-51.000,64.117,64.117) Greenland |
institution |
Open Polar |
collection |
Freie Universität Berlin: Refubium (FU Berlin) |
op_collection_id |
ftfuberlin |
language |
English |
topic |
Hadean differentiation Archean Mantle heterogeneity Isua supracrustal belt: 142Nd MC ICP-MS ddc:550 |
spellingShingle |
Hadean differentiation Archean Mantle heterogeneity Isua supracrustal belt: 142Nd MC ICP-MS ddc:550 Hasenstab-Dübeler, Eric Tusch, Jonas Hoffmann, J. Elis Fischer-Gödde, Mario Szilas, Kristoffer Münker, Carsten Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements |
topic_facet |
Hadean differentiation Archean Mantle heterogeneity Isua supracrustal belt: 142Nd MC ICP-MS ddc:550 |
description |
Measurements of 142Nd isotope signatures in Archean rocks are a powerful tool to investigate the earliest silicate differentiation events on Earth. Here, we introduce a new analytical protocol that allows high precision radiogenic and mass-independent Nd isotope measurements by MC-ICP-MS. To validate our method, we have measured well-characterized ∼3.72 to ∼3.8 Ga samples from the Eoarchean Itsaq Gneiss Complex and associated supracrustal belts, as well as Mesoarchean greenstones and a Proterozoic dike in SW Greenland, including lithostratigraphic units that were previously analyzed for 142-143Nd isotope systematics, by both TIMS and MC-ICP-MS. Our μ142Nd values for ∼3.72 to ∼3.8 Ga rocks from the Isua region range from +9.2 ± 2.6 to +13.2 ± 1.1 ppm and are in good agreement with previous studies. Using coupled 142,143Nd/144Nd isotope systematics from our data for ∼3.8 Ga mafic-ultramafic successions from the Isua region, we can confirm previous age constraints on the earliest silicate differentiation events with differentiation age of 4.390−0.060+0.045 Ga. Moreover, we can resolve a statistically significant decrease of 142Nd/144Nd isotope compositions in the ambient mantle of SW Greenland that already started to commence by Eoarchean time, between ∼3.8 Ga (μ142Nd = +13.0 ± 1.1) and ∼ 3.72 Ga (μ142Nd = +9.8 ± 1.0). Even lower but homogeneous μ142Nd values of +3.8 ± 1.1 are found in ∼3.4 Ga mantle-derived rocks from the Ameralik dike swarms. Our study reveals that ε143Nd(i) and εHf(i) values of Isua rocks scatter more than it would be expected from a single stage differentiation event as implied from nearly uniform μ142Nd values, suggesting that the previously described decoupling of Hf and Nd isotopes is not a primordial magma ocean signature. Instead, we conclude that some of second stage processes like younger mantle depletion events or recycling of subducted material affected the 147Smsingle bond143Nd isotope systematics. The preservation of pristine whole-rock isochrons largely rules out a significant ... |
format |
Article in Journal/Newspaper |
author |
Hasenstab-Dübeler, Eric Tusch, Jonas Hoffmann, J. Elis Fischer-Gödde, Mario Szilas, Kristoffer Münker, Carsten |
author_facet |
Hasenstab-Dübeler, Eric Tusch, Jonas Hoffmann, J. Elis Fischer-Gödde, Mario Szilas, Kristoffer Münker, Carsten |
author_sort |
Hasenstab-Dübeler, Eric |
title |
Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements |
title_short |
Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements |
title_full |
Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements |
title_fullStr |
Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements |
title_full_unstemmed |
Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements |
title_sort |
temporal evolution of 142nd signatures in sw greenland from high precision mc-icp-ms measurements |
publishDate |
2022 |
url |
https://refubium.fu-berlin.de/handle/fub188/37969 https://doi.org/10.17169/refubium-37685 https://doi.org/10.1016/j.chemgeo.2022.121141 |
long_lat |
ENVELOPE(-51.000,-51.000,64.117,64.117) |
geographic |
Ameralik Greenland |
geographic_facet |
Ameralik Greenland |
genre |
Ameralik Greenland |
genre_facet |
Ameralik Greenland |
op_relation |
https://refubium.fu-berlin.de/handle/fub188/37969 http://dx.doi.org/10.17169/refubium-37685 doi:10.1016/j.chemgeo.2022.121141 |
op_rights |
https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.17169/refubium-37685 https://doi.org/10.1016/j.chemgeo.2022.121141 |
_version_ |
1766361060386799616 |