Eoarchean within-plate basalts from southwest Greenland

The majority of >3 Ga metabasalts have chemical features, such as high field strength element (HFSE) depletions, that are characteristic of modern island-arc basalts. These compositions have been interpreted as evidence for subduction of oceanic crust early in Earth's history. Alternatively,...

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Main Authors: Jenner, Frances, Bennett, Victoria, Yaxley, Gregory, Friend, C R L, Nebel, Oliver
Format: Article in Journal/Newspaper
Language:unknown
Published: Geological Society of America Inc 2015
Subjects:
Online Access:http://hdl.handle.net/1885/71145
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record_format openpolar
spelling ftanucanberra:oai:digitalcollections.anu.edu.au:1885/71145 2023-05-15T16:27:53+02:00 Eoarchean within-plate basalts from southwest Greenland Jenner, Frances Bennett, Victoria Yaxley, Gregory Friend, C R L Nebel, Oliver 2015-12-13T22:17:28Z http://hdl.handle.net/1885/71145 unknown Geological Society of America Inc 0091-7613 http://hdl.handle.net/1885/71145 Geology Journal article 2015 ftanucanberra 2015-12-21T23:46:48Z The majority of >3 Ga metabasalts have chemical features, such as high field strength element (HFSE) depletions, that are characteristic of modern island-arc basalts. These compositions have been interpreted as evidence for subduction of oceanic crust early in Earth's history. Alternatively, the apparent absence of Archean mafic rocks with mid-oceanic ridge basalt (MORB) and ocean island basalt (OIB) compositions and the ubiquitous occurrence of metabasalts with HFSE anomalies suggest that these chemical features may instead be a widespread characteristic of the Archean mantle related to early chemical differentiation and unrelated to modern-style recycling of crust. Here we present major- and trace-element data for a suite of metabasalts from Innersuartuut Island, southwest Greenland, which have a minimum age constraint of 3.75 Ga and are likely as old as ≥3.85 Ga. Samples from Innersuartuut show no evidence for crustal contamination or subduction-related magmatism, and have a petrogenesis comparable to modern OIB. The new data demonstrate that a compositional range for volcanic rocks comparable to that seen in the Phanerozoic existed in the Eoarchean. Therefore, rather than a global anomaly, subduction-related processes are the likely origin for the compositions of the most commonly preserved Archean mafic rocks with island-arc basalt characteristics. Article in Journal/Newspaper Greenland Ocean Island Australian National University: ANU Digital Collections Greenland
institution Open Polar
collection Australian National University: ANU Digital Collections
op_collection_id ftanucanberra
language unknown
description The majority of >3 Ga metabasalts have chemical features, such as high field strength element (HFSE) depletions, that are characteristic of modern island-arc basalts. These compositions have been interpreted as evidence for subduction of oceanic crust early in Earth's history. Alternatively, the apparent absence of Archean mafic rocks with mid-oceanic ridge basalt (MORB) and ocean island basalt (OIB) compositions and the ubiquitous occurrence of metabasalts with HFSE anomalies suggest that these chemical features may instead be a widespread characteristic of the Archean mantle related to early chemical differentiation and unrelated to modern-style recycling of crust. Here we present major- and trace-element data for a suite of metabasalts from Innersuartuut Island, southwest Greenland, which have a minimum age constraint of 3.75 Ga and are likely as old as ≥3.85 Ga. Samples from Innersuartuut show no evidence for crustal contamination or subduction-related magmatism, and have a petrogenesis comparable to modern OIB. The new data demonstrate that a compositional range for volcanic rocks comparable to that seen in the Phanerozoic existed in the Eoarchean. Therefore, rather than a global anomaly, subduction-related processes are the likely origin for the compositions of the most commonly preserved Archean mafic rocks with island-arc basalt characteristics.
format Article in Journal/Newspaper
author Jenner, Frances
Bennett, Victoria
Yaxley, Gregory
Friend, C R L
Nebel, Oliver
spellingShingle Jenner, Frances
Bennett, Victoria
Yaxley, Gregory
Friend, C R L
Nebel, Oliver
Eoarchean within-plate basalts from southwest Greenland
author_facet Jenner, Frances
Bennett, Victoria
Yaxley, Gregory
Friend, C R L
Nebel, Oliver
author_sort Jenner, Frances
title Eoarchean within-plate basalts from southwest Greenland
title_short Eoarchean within-plate basalts from southwest Greenland
title_full Eoarchean within-plate basalts from southwest Greenland
title_fullStr Eoarchean within-plate basalts from southwest Greenland
title_full_unstemmed Eoarchean within-plate basalts from southwest Greenland
title_sort eoarchean within-plate basalts from southwest greenland
publisher Geological Society of America Inc
publishDate 2015
url http://hdl.handle.net/1885/71145
geographic Greenland
geographic_facet Greenland
genre Greenland
Ocean Island
genre_facet Greenland
Ocean Island
op_source Geology
op_relation 0091-7613
http://hdl.handle.net/1885/71145
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