Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis
Eoarchaean crust in West Greenland (the Itsaq Gneiss Complex, 3870-3600 Ma) is >80% by volume orthogneisses derived from plutonic tonalite-trondhjemite-granodiorite (TTG) suites,3850, c. 3810 and c. 3710 Mahave some compositional similarities to modern island arc basalts (IAB), suggesting their o...
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ftunivwollongong:oai:ro.uow.edu.au:scipapers-1923 2023-05-15T16:27:54+02:00 Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis Nutman, Allen P Bennett, Vickie C Friend, Clark R L Jenner, Frances Wan, Yusheng Liu, Dunyi 2009-01-01T08:00:00Z application/pdf https://ro.uow.edu.au/scipapers/884 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1923&context=scipapers unknown Research Online https://ro.uow.edu.au/scipapers/884 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1923&context=scipapers Faculty of Science - Papers (Archive) greenland west growth synthesis review area anshan china crustal northeastern eoarchaean complex gneiss itsaq GeoQUEST Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences article 2009 ftunivwollongong 2020-02-25T10:56:40Z Eoarchaean crust in West Greenland (the Itsaq Gneiss Complex, 3870-3600 Ma) is >80% by volume orthogneisses derived from plutonic tonalite-trondhjemite-granodiorite (TTG) suites,3850, c. 3810 and c. 3710 Mahave some compositional similarities to modern island arc basalts (IAB), suggesting their origin by hydrous fluxing of a suprasubduction-zone upper mantle wedge. Most of the Eoarchaean tonalites match in composition high-silica, low-magnesian adakites, whose petrogenesis is dominated by partial melting of garnetiferous mafic rocks at high pressure. However, associated with the tonalites are volumetrically minor more magnesian quartz diorites, whose genesis probably involved melting of depleted mantle to which some slab-derived component had been added. This assemblage is evocative of suites of magmas produced at Phanerozoic convergent plate boundaries in the case where subducted crust is young and hot. Thus, Eoarchaean 'subduction' first gave rise to short-lived episodes of mantle wedge melting by hydrous fluxing, yielding IAB-like basalts ± boninites. In the hotter Eoarchaean Earth, flux-dominated destructive plate boundary magma generation quickly switched to slab melting of ('subducted') oceanic crust. This latter process produced the voluminous tonalites that were intruded into the slightly older sequences consisting of tectonically imbricated assemblages of IAB-like pillow lavas + sedimentary rocks, gabbros and upper mantle peridotite slivers. Zircon datingshows that Eoarchaean TTG production in the Itsaq Gneiss Complex was episodic (3870, 3850-3840, 3820-3810, 3795, 3760-3740, 3710-3695 and 3660 Ma). In each case, emplacement of small volumes of magma was probably followed by 10-40 Maquiescence, which allowed the associated thermal pulse to dissipate. This explains why Greenland Eoarchaean crustal growth did not have granulite-facies metamorphismdirectly associated with it. Instead, 3660-3600 Ma granulite-facies metamorphism(s) in the Itsaq Gneiss Complex were consequential to collisional orogeny and underplating, upon termination of crustal growth. Similar Eoarchaean crustal history is recorded in the Anshan area of China, where a few well-preserved rocks as old as 3800 Ma have been found including high-MgO quartz diorites. For 3800 Ma rocks, this is a rare, if not unique, situation outside of the Itsaq Gneiss Complex. The presence of volumetrically minor 3800 Mamantle-derived high-MgO quartz diorites in both the Itsaq Gneiss Complex and the Anshan area indicates either that Eoarchaean 'subduction' zones were overlain by a narrow mantlewedge or that the shallow subduction trapped slivers of upper mantle between the conserved and consumed plates. © The Geological Society of London 2009. Article in Journal/Newspaper Greenland University of Wollongong, Australia: Research Online Greenland |
institution |
Open Polar |
collection |
University of Wollongong, Australia: Research Online |
op_collection_id |
ftunivwollongong |
language |
unknown |
topic |
greenland west growth synthesis review area anshan china crustal northeastern eoarchaean complex gneiss itsaq GeoQUEST Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences |
spellingShingle |
greenland west growth synthesis review area anshan china crustal northeastern eoarchaean complex gneiss itsaq GeoQUEST Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences Nutman, Allen P Bennett, Vickie C Friend, Clark R L Jenner, Frances Wan, Yusheng Liu, Dunyi Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis |
topic_facet |
greenland west growth synthesis review area anshan china crustal northeastern eoarchaean complex gneiss itsaq GeoQUEST Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences |
description |
Eoarchaean crust in West Greenland (the Itsaq Gneiss Complex, 3870-3600 Ma) is >80% by volume orthogneisses derived from plutonic tonalite-trondhjemite-granodiorite (TTG) suites,3850, c. 3810 and c. 3710 Mahave some compositional similarities to modern island arc basalts (IAB), suggesting their origin by hydrous fluxing of a suprasubduction-zone upper mantle wedge. Most of the Eoarchaean tonalites match in composition high-silica, low-magnesian adakites, whose petrogenesis is dominated by partial melting of garnetiferous mafic rocks at high pressure. However, associated with the tonalites are volumetrically minor more magnesian quartz diorites, whose genesis probably involved melting of depleted mantle to which some slab-derived component had been added. This assemblage is evocative of suites of magmas produced at Phanerozoic convergent plate boundaries in the case where subducted crust is young and hot. Thus, Eoarchaean 'subduction' first gave rise to short-lived episodes of mantle wedge melting by hydrous fluxing, yielding IAB-like basalts ± boninites. In the hotter Eoarchaean Earth, flux-dominated destructive plate boundary magma generation quickly switched to slab melting of ('subducted') oceanic crust. This latter process produced the voluminous tonalites that were intruded into the slightly older sequences consisting of tectonically imbricated assemblages of IAB-like pillow lavas + sedimentary rocks, gabbros and upper mantle peridotite slivers. Zircon datingshows that Eoarchaean TTG production in the Itsaq Gneiss Complex was episodic (3870, 3850-3840, 3820-3810, 3795, 3760-3740, 3710-3695 and 3660 Ma). In each case, emplacement of small volumes of magma was probably followed by 10-40 Maquiescence, which allowed the associated thermal pulse to dissipate. This explains why Greenland Eoarchaean crustal growth did not have granulite-facies metamorphismdirectly associated with it. Instead, 3660-3600 Ma granulite-facies metamorphism(s) in the Itsaq Gneiss Complex were consequential to collisional orogeny and underplating, upon termination of crustal growth. Similar Eoarchaean crustal history is recorded in the Anshan area of China, where a few well-preserved rocks as old as 3800 Ma have been found including high-MgO quartz diorites. For 3800 Ma rocks, this is a rare, if not unique, situation outside of the Itsaq Gneiss Complex. The presence of volumetrically minor 3800 Mamantle-derived high-MgO quartz diorites in both the Itsaq Gneiss Complex and the Anshan area indicates either that Eoarchaean 'subduction' zones were overlain by a narrow mantlewedge or that the shallow subduction trapped slivers of upper mantle between the conserved and consumed plates. © The Geological Society of London 2009. |
format |
Article in Journal/Newspaper |
author |
Nutman, Allen P Bennett, Vickie C Friend, Clark R L Jenner, Frances Wan, Yusheng Liu, Dunyi |
author_facet |
Nutman, Allen P Bennett, Vickie C Friend, Clark R L Jenner, Frances Wan, Yusheng Liu, Dunyi |
author_sort |
Nutman, Allen P |
title |
Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis |
title_short |
Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis |
title_full |
Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis |
title_fullStr |
Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis |
title_full_unstemmed |
Eoarchaean crustal growth in West Greenland (Itsaq Gneiss Complex) and in northeastern China (Anshan area): review and synthesis |
title_sort |
eoarchaean crustal growth in west greenland (itsaq gneiss complex) and in northeastern china (anshan area): review and synthesis |
publisher |
Research Online |
publishDate |
2009 |
url |
https://ro.uow.edu.au/scipapers/884 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1923&context=scipapers |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Faculty of Science - Papers (Archive) |
op_relation |
https://ro.uow.edu.au/scipapers/884 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1923&context=scipapers |
_version_ |
1766017461193277440 |