Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland
The oldest known bona fide succession of elastic metasediments Occurs in the Isua Greenstone Belt. SW Greenland and consists of a variety of mica schists and rare metaconglomerates. The metasediments are in direct contact with a felsic metavolcanic lithology that has previously been dated to 3.71 Ga...
Published in: | Earth and Planetary Science Letters |
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Language: | English |
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2005
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ftunivqespace:oai:espace.library.uq.edu.au:UQ:78161 2023-05-15T16:28:12+02:00 Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland Kamber, B. S. Whitehouse, M. J. Bolhar, R. Moorbath, S. 2005-01-01 https://espace.library.uq.edu.au/view/UQ:78161 eng eng Elsevier Science BV doi:10.1016/j.epsl.2005.09.037 issn:0012-821X Geochemistry & Geophysics Early Archaean Hadean Basaltic Resurfacing Zircon Dating Nd-isotope Heterogeneity Old Detrital Zircons Rare-earth-elements Trace-element Southwest Greenland Continental-crust Supracrustal Belt Northern Canada Case-histories Liquid Water 260301 Geochronology and Isotope Geochemistry C1 780104 Earth sciences 0499 Other Earth Sciences Journal Article 2005 ftunivqespace https://doi.org/10.1016/j.epsl.2005.09.037 2020-10-05T22:32:24Z The oldest known bona fide succession of elastic metasediments Occurs in the Isua Greenstone Belt. SW Greenland and consists of a variety of mica schists and rare metaconglomerates. The metasediments are in direct contact with a felsic metavolcanic lithology that has previously been dated to 3.71 Ga. Based on trace element geochemical data for 30 metasediments, we selected the six samples with highest Zr concentrations for zircon extraction. These samples all yielded very few or no zircon, Those extracted from mica schists yielded ion probe U/Pb ages between 3.70 and 3,71 Ga. One metaconglomerate sample yielded just a single zircon of 3.74 Ga age. The mica schist hosted zircons have U/Pb ages. Th/U ratios, REE patterns and Eu anomalies indistinguishable from zircon in the adjacent 3.71 Ga felsic metavolcanic unit. Trace element modelling requires the bulk of material in the metasediments to be derived from variably weathered mafic lithologies but some metasediments contain substantial contribution from more evolved source lithologies. The paucity of zircon in the mica schists is thus explained by incorporation of material from largely zircon-free volcanic lithologies. The absence of older zircon in the mica schists and the preponderance of mafic source material imply intense, mainly basaltic resurfacing of the early Earth. The implications of this process are discussed, Thermal considerations suggest that horizontal growth of Hadean crust by addition of mafic ultramafic lavas must have triggered self-reorganisation of the protocrust by remelting. Reworking oft Hadean crust may have been aided by burial of hydrated (weathered) metabasalt due to semi-continuous addition of new voluminous basalt Outpouring,;, This process Causes a bias towards eruption of Zr-saturated partial melts at the surface with O-isotope corn posit ion,, potentially different from the mantle. The oldest zircons hosted in sediments would have been buried to substantial depth or formed in plutons that crystallised at some depth from which it took hundreds of millions of years for them to be exhumed and incorporated into much younger sediments. (C) 2005 Elsevier B.V.All rights reserved. Article in Journal/Newspaper Greenland The University of Queensland: UQ eSpace Canada Greenland Earth and Planetary Science Letters 240 2 276 290 |
institution |
Open Polar |
collection |
The University of Queensland: UQ eSpace |
op_collection_id |
ftunivqespace |
language |
English |
topic |
Geochemistry & Geophysics Early Archaean Hadean Basaltic Resurfacing Zircon Dating Nd-isotope Heterogeneity Old Detrital Zircons Rare-earth-elements Trace-element Southwest Greenland Continental-crust Supracrustal Belt Northern Canada Case-histories Liquid Water 260301 Geochronology and Isotope Geochemistry C1 780104 Earth sciences 0499 Other Earth Sciences |
spellingShingle |
Geochemistry & Geophysics Early Archaean Hadean Basaltic Resurfacing Zircon Dating Nd-isotope Heterogeneity Old Detrital Zircons Rare-earth-elements Trace-element Southwest Greenland Continental-crust Supracrustal Belt Northern Canada Case-histories Liquid Water 260301 Geochronology and Isotope Geochemistry C1 780104 Earth sciences 0499 Other Earth Sciences Kamber, B. S. Whitehouse, M. J. Bolhar, R. Moorbath, S. Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland |
topic_facet |
Geochemistry & Geophysics Early Archaean Hadean Basaltic Resurfacing Zircon Dating Nd-isotope Heterogeneity Old Detrital Zircons Rare-earth-elements Trace-element Southwest Greenland Continental-crust Supracrustal Belt Northern Canada Case-histories Liquid Water 260301 Geochronology and Isotope Geochemistry C1 780104 Earth sciences 0499 Other Earth Sciences |
description |
The oldest known bona fide succession of elastic metasediments Occurs in the Isua Greenstone Belt. SW Greenland and consists of a variety of mica schists and rare metaconglomerates. The metasediments are in direct contact with a felsic metavolcanic lithology that has previously been dated to 3.71 Ga. Based on trace element geochemical data for 30 metasediments, we selected the six samples with highest Zr concentrations for zircon extraction. These samples all yielded very few or no zircon, Those extracted from mica schists yielded ion probe U/Pb ages between 3.70 and 3,71 Ga. One metaconglomerate sample yielded just a single zircon of 3.74 Ga age. The mica schist hosted zircons have U/Pb ages. Th/U ratios, REE patterns and Eu anomalies indistinguishable from zircon in the adjacent 3.71 Ga felsic metavolcanic unit. Trace element modelling requires the bulk of material in the metasediments to be derived from variably weathered mafic lithologies but some metasediments contain substantial contribution from more evolved source lithologies. The paucity of zircon in the mica schists is thus explained by incorporation of material from largely zircon-free volcanic lithologies. The absence of older zircon in the mica schists and the preponderance of mafic source material imply intense, mainly basaltic resurfacing of the early Earth. The implications of this process are discussed, Thermal considerations suggest that horizontal growth of Hadean crust by addition of mafic ultramafic lavas must have triggered self-reorganisation of the protocrust by remelting. Reworking oft Hadean crust may have been aided by burial of hydrated (weathered) metabasalt due to semi-continuous addition of new voluminous basalt Outpouring,;, This process Causes a bias towards eruption of Zr-saturated partial melts at the surface with O-isotope corn posit ion,, potentially different from the mantle. The oldest zircons hosted in sediments would have been buried to substantial depth or formed in plutons that crystallised at some depth from which it took hundreds of millions of years for them to be exhumed and incorporated into much younger sediments. (C) 2005 Elsevier B.V.All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Kamber, B. S. Whitehouse, M. J. Bolhar, R. Moorbath, S. |
author_facet |
Kamber, B. S. Whitehouse, M. J. Bolhar, R. Moorbath, S. |
author_sort |
Kamber, B. S. |
title |
Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland |
title_short |
Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland |
title_full |
Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland |
title_fullStr |
Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland |
title_full_unstemmed |
Volcanic resurfacing and the early terrestrial crust: Zircon U-Pb and REE constraints from the Isua Greenstone Belt, southern West Greenland |
title_sort |
volcanic resurfacing and the early terrestrial crust: zircon u-pb and ree constraints from the isua greenstone belt, southern west greenland |
publisher |
Elsevier Science BV |
publishDate |
2005 |
url |
https://espace.library.uq.edu.au/view/UQ:78161 |
geographic |
Canada Greenland |
geographic_facet |
Canada Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_relation |
doi:10.1016/j.epsl.2005.09.037 issn:0012-821X |
op_doi |
https://doi.org/10.1016/j.epsl.2005.09.037 |
container_title |
Earth and Planetary Science Letters |
container_volume |
240 |
container_issue |
2 |
container_start_page |
276 |
op_container_end_page |
290 |
_version_ |
1766017834134011904 |