Earth's oldest mantle fabrics indicate Eoarchaean subduction
The extension of subduction processes into the Eoarchaean era (4.0-3.6 Ga) is controversial. The oldest reported terrestrial olivine, from two dunite lenses within the ~3,720 Ma Isua supracrustal belt in Greenland, record a shape-preferred orientation of olivine crystals defining a weak foliation an...
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ftunivwollongong:oai:ro.uow.edu.au:smhpapers-4827 2023-05-15T16:29:05+02:00 Earth's oldest mantle fabrics indicate Eoarchaean subduction Kaczmarek, Mary-Alix Reddy, Steven Nutman, Allen Phillip Friend, Clark R. L Bennett, Vickie C 2016-01-01T08:00:00Z application/pdf https://ro.uow.edu.au/smhpapers/3804 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4827&context=smhpapers unknown Research Online https://ro.uow.edu.au/smhpapers/3804 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4827&context=smhpapers Faculty of Science, Medicine and Health - Papers: part A Medicine and Health Sciences Social and Behavioral Sciences article 2016 ftunivwollongong 2020-02-25T11:26:37Z The extension of subduction processes into the Eoarchaean era (4.0-3.6 Ga) is controversial. The oldest reported terrestrial olivine, from two dunite lenses within the ~3,720 Ma Isua supracrustal belt in Greenland, record a shape-preferred orientation of olivine crystals defining a weak foliation and a well-defined lattice-preferred orientation (LPO). [001] parallel to the maximum finite elongation direction and (010) perpendicular to the foliation plane define a B-type LPO. In the modern Earth such fabrics are associated with deformation of mantle rocks in the hanging wall of subduction systems; an interpretation supported by experiments. Here we show that the presence of B-type fabrics in the studied Isua dunites is consistent with a mantle origin and a supra-subduction mantle wedge setting, the latter supported by compositional data from nearby mafic rocks. Our results provide independent microstructural data consistent with the operation of Eoarchaean subduction and indicate that microstructural analyses of ancient ultramafic rocks provide a valuable record of Archaean geodynamics. Article in Journal/Newspaper Greenland University of Wollongong, Australia: Research Online Greenland |
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University of Wollongong, Australia: Research Online |
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ftunivwollongong |
language |
unknown |
topic |
Medicine and Health Sciences Social and Behavioral Sciences |
spellingShingle |
Medicine and Health Sciences Social and Behavioral Sciences Kaczmarek, Mary-Alix Reddy, Steven Nutman, Allen Phillip Friend, Clark R. L Bennett, Vickie C Earth's oldest mantle fabrics indicate Eoarchaean subduction |
topic_facet |
Medicine and Health Sciences Social and Behavioral Sciences |
description |
The extension of subduction processes into the Eoarchaean era (4.0-3.6 Ga) is controversial. The oldest reported terrestrial olivine, from two dunite lenses within the ~3,720 Ma Isua supracrustal belt in Greenland, record a shape-preferred orientation of olivine crystals defining a weak foliation and a well-defined lattice-preferred orientation (LPO). [001] parallel to the maximum finite elongation direction and (010) perpendicular to the foliation plane define a B-type LPO. In the modern Earth such fabrics are associated with deformation of mantle rocks in the hanging wall of subduction systems; an interpretation supported by experiments. Here we show that the presence of B-type fabrics in the studied Isua dunites is consistent with a mantle origin and a supra-subduction mantle wedge setting, the latter supported by compositional data from nearby mafic rocks. Our results provide independent microstructural data consistent with the operation of Eoarchaean subduction and indicate that microstructural analyses of ancient ultramafic rocks provide a valuable record of Archaean geodynamics. |
format |
Article in Journal/Newspaper |
author |
Kaczmarek, Mary-Alix Reddy, Steven Nutman, Allen Phillip Friend, Clark R. L Bennett, Vickie C |
author_facet |
Kaczmarek, Mary-Alix Reddy, Steven Nutman, Allen Phillip Friend, Clark R. L Bennett, Vickie C |
author_sort |
Kaczmarek, Mary-Alix |
title |
Earth's oldest mantle fabrics indicate Eoarchaean subduction |
title_short |
Earth's oldest mantle fabrics indicate Eoarchaean subduction |
title_full |
Earth's oldest mantle fabrics indicate Eoarchaean subduction |
title_fullStr |
Earth's oldest mantle fabrics indicate Eoarchaean subduction |
title_full_unstemmed |
Earth's oldest mantle fabrics indicate Eoarchaean subduction |
title_sort |
earth's oldest mantle fabrics indicate eoarchaean subduction |
publisher |
Research Online |
publishDate |
2016 |
url |
https://ro.uow.edu.au/smhpapers/3804 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4827&context=smhpapers |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Faculty of Science, Medicine and Health - Papers: part A |
op_relation |
https://ro.uow.edu.au/smhpapers/3804 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4827&context=smhpapers |
_version_ |
1766018770082463744 |