Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates?
When plate tectonics initiated remains uncertain, partly because many signals interpreted as diagnostic of plate tectonics can be alternatively explained via hot stagnant-lid tectonics. One such signal involves the petrogenesis of early Archean phaneritic ultramafic rocks. In the Eoarchean Isua supr...
Published in: | Geochemistry, Geophysics, Geosystems |
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Online Access: | https://resolver.sub.uni-goettingen.de/purl?gro-2/117283 https://doi.org/10.1029/2022GC010519 |
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ftsubgoettingen:oai:publications.goettingen-research-online.de:2/117283 2023-12-24T10:17:13+01:00 Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? Zuo, Jiawei Webb, A. Alexander G. Chin, Emily J. Ackerman, Lukáš Harvey, Jason Haproff, Peter J. Müller, Thomas Wang, Qin Hickman, Arthur H. Sorger, Dominik Ramírez‐Salazar, Anthony Zuo, Jiawei Webb, A. Alexander G. Chin, Emily J. Ackerman, Lukáš Harvey, Jason Haproff, Peter J. Müller, Thomas Wang, Qin Hickman, Arthur H. Sorger, Dominik Ramírez‐Salazar, Anthony 2022 https://resolver.sub.uni-goettingen.de/purl?gro-2/117283 https://doi.org/10.1029/2022GC010519 en eng https://resolver.sub.uni-goettingen.de/purl?gro-2/117283 doi:10.1029/2022GC010519 info:eu-repo/semantics/openAccess CC BY-NC-ND 4.0 info:eu-repo/semantics/article journal_article yes published_version 2022 ftsubgoettingen https://doi.org/10.1029/2022GC010519 2023-11-26T23:11:58Z When plate tectonics initiated remains uncertain, partly because many signals interpreted as diagnostic of plate tectonics can be alternatively explained via hot stagnant-lid tectonics. One such signal involves the petrogenesis of early Archean phaneritic ultramafic rocks. In the Eoarchean Isua supracrustal belt (Greenland), some phaneritic ultramafic rocks have been dominantly interpreted as subduction-related, tectonically-exhumed mantle slices or cumulates. Here, we compared Eoarchean phaneritic ultramafic rocks from the Isua supracrustal belt with mantle peridotites, cumulates, and phaneritic ultramafic samples from the Paleoarchean East Pilbara Terrane (Australia), which is widely interpreted to have formed in non-plate tectonic settings. Our findings show that Pilbara samples have cumulate and polygonal textures, melt-enriched trace element patterns, relative enrichment of Os, Ir, and Ru versus Pt and Pd, and chromite-spinel with variable TiO2 and Mg#, and relatively consistent Cr#. Both, new and existing data show that cumulates and mantle rocks potentially have similar whole-rock geochemical characteristics, deformation fabrics, and alteration features. Geochemical modeling results indicate that Isua and Pilbara ultramafic rocks have interacted with low-Pt and Pd melts generated by sequestration of Pd and Pt into sulphide and/or alloy during magmatism. Such melts cannot have interacted with a mantle wedge. Correspondingly, geochemical compositions and rock textures suggest that Isua and Pilbara ultramafic rocks are not tectonically-exhumed mantle peridotites, but are cumulates that experienced metasomatism by fluids and co-genetic melts. Because such rocks could have formed in either plate or non-plate tectonic settings, they cannot be used to differentiate early Earth tectonic settings. Article in Journal/Newspaper Greenland GRO.publications (Göttingen Research Online Publications - Göttingen University) Greenland Geochemistry, Geophysics, Geosystems 23 12 |
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Open Polar |
collection |
GRO.publications (Göttingen Research Online Publications - Göttingen University) |
op_collection_id |
ftsubgoettingen |
language |
English |
description |
When plate tectonics initiated remains uncertain, partly because many signals interpreted as diagnostic of plate tectonics can be alternatively explained via hot stagnant-lid tectonics. One such signal involves the petrogenesis of early Archean phaneritic ultramafic rocks. In the Eoarchean Isua supracrustal belt (Greenland), some phaneritic ultramafic rocks have been dominantly interpreted as subduction-related, tectonically-exhumed mantle slices or cumulates. Here, we compared Eoarchean phaneritic ultramafic rocks from the Isua supracrustal belt with mantle peridotites, cumulates, and phaneritic ultramafic samples from the Paleoarchean East Pilbara Terrane (Australia), which is widely interpreted to have formed in non-plate tectonic settings. Our findings show that Pilbara samples have cumulate and polygonal textures, melt-enriched trace element patterns, relative enrichment of Os, Ir, and Ru versus Pt and Pd, and chromite-spinel with variable TiO2 and Mg#, and relatively consistent Cr#. Both, new and existing data show that cumulates and mantle rocks potentially have similar whole-rock geochemical characteristics, deformation fabrics, and alteration features. Geochemical modeling results indicate that Isua and Pilbara ultramafic rocks have interacted with low-Pt and Pd melts generated by sequestration of Pd and Pt into sulphide and/or alloy during magmatism. Such melts cannot have interacted with a mantle wedge. Correspondingly, geochemical compositions and rock textures suggest that Isua and Pilbara ultramafic rocks are not tectonically-exhumed mantle peridotites, but are cumulates that experienced metasomatism by fluids and co-genetic melts. Because such rocks could have formed in either plate or non-plate tectonic settings, they cannot be used to differentiate early Earth tectonic settings. |
author2 |
Zuo, Jiawei Webb, A. Alexander G. Chin, Emily J. Ackerman, Lukáš Harvey, Jason Haproff, Peter J. Müller, Thomas Wang, Qin Hickman, Arthur H. Sorger, Dominik Ramírez‐Salazar, Anthony |
format |
Article in Journal/Newspaper |
author |
Zuo, Jiawei Webb, A. Alexander G. Chin, Emily J. Ackerman, Lukáš Harvey, Jason Haproff, Peter J. Müller, Thomas Wang, Qin Hickman, Arthur H. Sorger, Dominik Ramírez‐Salazar, Anthony |
spellingShingle |
Zuo, Jiawei Webb, A. Alexander G. Chin, Emily J. Ackerman, Lukáš Harvey, Jason Haproff, Peter J. Müller, Thomas Wang, Qin Hickman, Arthur H. Sorger, Dominik Ramírez‐Salazar, Anthony Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? |
author_facet |
Zuo, Jiawei Webb, A. Alexander G. Chin, Emily J. Ackerman, Lukáš Harvey, Jason Haproff, Peter J. Müller, Thomas Wang, Qin Hickman, Arthur H. Sorger, Dominik Ramírez‐Salazar, Anthony |
author_sort |
Zuo, Jiawei |
title |
Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? |
title_short |
Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? |
title_full |
Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? |
title_fullStr |
Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? |
title_full_unstemmed |
Earth’s earliest phaneritic ultramafic rocks: Mantle slices or crustal cumulates? |
title_sort |
earth’s earliest phaneritic ultramafic rocks: mantle slices or crustal cumulates? |
publishDate |
2022 |
url |
https://resolver.sub.uni-goettingen.de/purl?gro-2/117283 https://doi.org/10.1029/2022GC010519 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_relation |
https://resolver.sub.uni-goettingen.de/purl?gro-2/117283 doi:10.1029/2022GC010519 |
op_rights |
info:eu-repo/semantics/openAccess CC BY-NC-ND 4.0 |
op_doi |
https://doi.org/10.1029/2022GC010519 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
23 |
container_issue |
12 |
_version_ |
1786205201682661376 |