Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland
New and published major and trace element abundances of elastic metasediments (mainly garnet-biotite-plagioclase schists) from the similar to 3.8 Ga Isua Greenstone Belt (IGB), southern West Greenland, are used in an attempt to identify the compositional characteristics of the protoliths of these se...
Published in: | Geochimica et Cosmochimica Acta |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Elsevier Ltd.
2005
|
Subjects: | |
Online Access: | https://eprints.qut.edu.au/126169/ |
id |
ftqueensland:oai:eprints.qut.edu.au:126169 |
---|---|
record_format |
openpolar |
spelling |
ftqueensland:oai:eprints.qut.edu.au:126169 2024-04-28T08:21:36+00:00 Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland Bolhar, R. Kamber, B. S. Moorbath, S. Whitehouse, M. J. Collerson, K. D. 2005 https://eprints.qut.edu.au/126169/ unknown Elsevier Ltd. doi:10.1016/j.gca.2004.09.023 Bolhar, R., Kamber, B. S., Moorbath, S., Whitehouse, M. J., & Collerson, K. D. (2005) Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland. Geochimica et Cosmochimica Acta, 69(6), pp. 1555-1573. https://eprints.qut.edu.au/126169/ Science & Engineering Faculty; Australian Research Centre for Aerospace Automation Consult author(s) regarding copyright matters This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the document is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recognise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to qut.copyright@qut.edu.au Geochimica et Cosmochimica Acta archean crustal evolution nd-isotope heterogeneity u-pb ages supracrustal belt continental-crust sedimentary-rocks core formation metamorphosed sediments zr/hf fractionation detrital zircons Geochemistry & Geophysics Contribution to Journal 2005 ftqueensland https://doi.org/10.1016/j.gca.2004.09.023 2024-04-03T15:11:16Z New and published major and trace element abundances of elastic metasediments (mainly garnet-biotite-plagioclase schists) from the similar to 3.8 Ga Isua Greenstone Belt (IGB), southern West Greenland, are used in an attempt to identify the compositional characteristics of the protoliths of these sediments. Compositionally, the metasediments are heterogeneous with enrichment of LREE (La/Sm-chord = 1.1-3.9) and variable enrichment and depletion of HREE (Gd/Yb-chord = 0.8-4.3). Chondrite-normalized Eu is also variable, spanning a range from relative Eu depletion to enrichment (Eu/Eu* = 0.6-1.3). A series of geochemical and geological criteria provides conclusive evidence for a sedimentary origin, in disagreement with some previous studies that questioned the presence of genuine elastic metasediments. In particular, trace element systematics of IGB metasediments show strong resemblance to other well-documented Archaean clastic sediments, and are consistent with a provenance consisting of ultramafic, malic and felsic igneous rocks. Two schists, identified as metasomatized mafic igneous rocks from petrographic and field evidence, show distinct compositional differences to the metasediments. Major element systematics document incipient-to-moderate source weathering in the majority of metasediments, while signs of secondary K-addition are rare. Detailed inspection of Eu/Eu*, Fe2O3 and CIW (chemical index of weathering) relationships reveals that elevated iron contents (when compared to averages for continental crust) and strong relative enrichment in Eu may be due to precipitation of marine Fe-oxyhydroxides during deposition or diagenesis on the seafloor. Some of the IGB metasediments have yielded anomalous Nd-142 and W-182 isotopic compositions that were respectively interpreted in terms of early mantle differentiation processes and the presence of a meteorite component. Alternatively, W and possibly Nd isotopes could have been affected by thermal neutron capture on the Hadean surface. The latter process was tested in ... Article in Journal/Newspaper Greenland Queensland University of Technology: QUT ePrints Geochimica et Cosmochimica Acta 69 6 1555 1573 |
institution |
Open Polar |
collection |
Queensland University of Technology: QUT ePrints |
op_collection_id |
ftqueensland |
language |
unknown |
topic |
archean crustal evolution nd-isotope heterogeneity u-pb ages supracrustal belt continental-crust sedimentary-rocks core formation metamorphosed sediments zr/hf fractionation detrital zircons Geochemistry & Geophysics |
spellingShingle |
archean crustal evolution nd-isotope heterogeneity u-pb ages supracrustal belt continental-crust sedimentary-rocks core formation metamorphosed sediments zr/hf fractionation detrital zircons Geochemistry & Geophysics Bolhar, R. Kamber, B. S. Moorbath, S. Whitehouse, M. J. Collerson, K. D. Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland |
topic_facet |
archean crustal evolution nd-isotope heterogeneity u-pb ages supracrustal belt continental-crust sedimentary-rocks core formation metamorphosed sediments zr/hf fractionation detrital zircons Geochemistry & Geophysics |
description |
New and published major and trace element abundances of elastic metasediments (mainly garnet-biotite-plagioclase schists) from the similar to 3.8 Ga Isua Greenstone Belt (IGB), southern West Greenland, are used in an attempt to identify the compositional characteristics of the protoliths of these sediments. Compositionally, the metasediments are heterogeneous with enrichment of LREE (La/Sm-chord = 1.1-3.9) and variable enrichment and depletion of HREE (Gd/Yb-chord = 0.8-4.3). Chondrite-normalized Eu is also variable, spanning a range from relative Eu depletion to enrichment (Eu/Eu* = 0.6-1.3). A series of geochemical and geological criteria provides conclusive evidence for a sedimentary origin, in disagreement with some previous studies that questioned the presence of genuine elastic metasediments. In particular, trace element systematics of IGB metasediments show strong resemblance to other well-documented Archaean clastic sediments, and are consistent with a provenance consisting of ultramafic, malic and felsic igneous rocks. Two schists, identified as metasomatized mafic igneous rocks from petrographic and field evidence, show distinct compositional differences to the metasediments. Major element systematics document incipient-to-moderate source weathering in the majority of metasediments, while signs of secondary K-addition are rare. Detailed inspection of Eu/Eu*, Fe2O3 and CIW (chemical index of weathering) relationships reveals that elevated iron contents (when compared to averages for continental crust) and strong relative enrichment in Eu may be due to precipitation of marine Fe-oxyhydroxides during deposition or diagenesis on the seafloor. Some of the IGB metasediments have yielded anomalous Nd-142 and W-182 isotopic compositions that were respectively interpreted in terms of early mantle differentiation processes and the presence of a meteorite component. Alternatively, W and possibly Nd isotopes could have been affected by thermal neutron capture on the Hadean surface. The latter process was tested in ... |
format |
Article in Journal/Newspaper |
author |
Bolhar, R. Kamber, B. S. Moorbath, S. Whitehouse, M. J. Collerson, K. D. |
author_facet |
Bolhar, R. Kamber, B. S. Moorbath, S. Whitehouse, M. J. Collerson, K. D. |
author_sort |
Bolhar, R. |
title |
Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland |
title_short |
Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland |
title_full |
Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland |
title_fullStr |
Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland |
title_full_unstemmed |
Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland |
title_sort |
chemical characterization of earth's most ancient clastic metasediments from the isua greenstone belt, southern west greenland |
publisher |
Elsevier Ltd. |
publishDate |
2005 |
url |
https://eprints.qut.edu.au/126169/ |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Geochimica et Cosmochimica Acta |
op_relation |
doi:10.1016/j.gca.2004.09.023 Bolhar, R., Kamber, B. S., Moorbath, S., Whitehouse, M. J., & Collerson, K. D. (2005) Chemical characterization of earth's most ancient clastic metasediments from the Isua Greenstone Belt, southern West Greenland. Geochimica et Cosmochimica Acta, 69(6), pp. 1555-1573. https://eprints.qut.edu.au/126169/ Science & Engineering Faculty; Australian Research Centre for Aerospace Automation |
op_rights |
Consult author(s) regarding copyright matters This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the document is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recognise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to qut.copyright@qut.edu.au |
op_doi |
https://doi.org/10.1016/j.gca.2004.09.023 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
69 |
container_issue |
6 |
container_start_page |
1555 |
op_container_end_page |
1573 |
_version_ |
1797583860884570112 |