Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica
Extensive high-grade polydeformed metamorphic provinces surrounding Archaean cratonic nuclei in the East Antarctic Shield record two tectono-thermal episodes in late Mesoproterozoic and late Neoproterozoic-Cambrian times. In Western Dronning Maud Land, the high-grade Mesoproterozoic Maud Belt is jux...
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ftanucanberra:oai:digitalcollections.anu.edu.au:1885/79206 2023-05-15T13:56:44+02:00 Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica Board, W.S. Frimmel, H E Armstrong, Richard 2015-12-13T22:43:26Z http://hdl.handle.net/1885/79206 unknown Oxford University Press 0022-3530 http://hdl.handle.net/1885/79206 Journal of Petrology Keywords: deformation metamorphic rock P-T-t path Proterozoic tectonic evolution Antarctica Arctic and Antarctic East Antarctica Queen Maud Land World Archaea Laurentia East Antarctica Geochronology Maud Belt Pan-African orogeny Journal article 2015 ftanucanberra 2015-12-21T23:51:54Z Extensive high-grade polydeformed metamorphic provinces surrounding Archaean cratonic nuclei in the East Antarctic Shield record two tectono-thermal episodes in late Mesoproterozoic and late Neoproterozoic-Cambrian times. In Western Dronning Maud Land, the high-grade Mesoproterozoic Maud Belt is juxtaposed against the Archaean Grunehogna Province and has traditionally been interpreted as a Grenvillian mobile belt that was thermally overprinted during the Early Palaeozoic. Integration of new U-Pb sensitive high-resolution ion microprobe and conventional single zircon and monazite age data, and Ar-Ar data on hornblende and biotite, with thermobarometric calculations on rocks from the H.U. Sverdrupfjella, northern Maud Belt, resulted in a more complex P-T-t evolution than previousyl assumed. A c. 540 Ma monazite, hosted by an upper ampibolite-facies mineral assemblage defining a regionally dominant top-to-NW shear fabric, provides strong evidence for the penetrative deformation in the area being of Pan-African age and not of Grenvillian age as previously reported. Relics of an eclogite-facies garnet-omphacite assemblage within strain-protected mafic boudins indicate that the peak metamorphic conditions recorded by most rocks in the area (T = 687-758°C, P = 9·4-11·3 kbar) were attained subsequent to decompression from P > 12·9 kbar. By analogy with limited U-Pb single zircon age data and on circumstantial textural grounds, this earlier eclogite-facies metamorphism is ascribed to subduction and accretion around 565 Ma. Post-peak metamorphic K-metasomatism under amphibolite-facies conditions is ascribed to the intrusion of post-orogenic granite at c. 480 Ma. The recognition of extensive Pan-African tectonism in the Maud Belt casts doubts on previous Rodinia reconstructions, in which this belt takes a pivotal position between East Antarctica, the Kalahari Craton and Laurentia. Evidence of late Mesoproterozoic high-grade metamorphism during the formation of the Maud Belt exists in the form of c. 1035 Ma zircon overgrowths that are probably related to relics of granulite-facies metamorphism recorded from other parts of the Maud Belt. The polymetamorphic rocks are largely derived from a c. 1140 Ma volcanic arc and 1072 ± 10 Ma granite. Article in Journal/Newspaper Antarc* Antarctic Antarctica Arctic Dronning Maud Land East Antarctica Queen Maud Land Australian National University: ANU Digital Collections Antarctic Arctic Dronning Maud Land East Antarctica Grunehogna ENVELOPE(-2.750,-2.750,-72.033,-72.033) Queen Maud Land ENVELOPE(12.000,12.000,-72.500,-72.500) Sverdrupfjella ENVELOPE(0.583,0.583,-72.700,-72.700) |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
unknown |
topic |
Keywords: deformation metamorphic rock P-T-t path Proterozoic tectonic evolution Antarctica Arctic and Antarctic East Antarctica Queen Maud Land World Archaea Laurentia East Antarctica Geochronology Maud Belt Pan-African orogeny |
spellingShingle |
Keywords: deformation metamorphic rock P-T-t path Proterozoic tectonic evolution Antarctica Arctic and Antarctic East Antarctica Queen Maud Land World Archaea Laurentia East Antarctica Geochronology Maud Belt Pan-African orogeny Board, W.S. Frimmel, H E Armstrong, Richard Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica |
topic_facet |
Keywords: deformation metamorphic rock P-T-t path Proterozoic tectonic evolution Antarctica Arctic and Antarctic East Antarctica Queen Maud Land World Archaea Laurentia East Antarctica Geochronology Maud Belt Pan-African orogeny |
description |
Extensive high-grade polydeformed metamorphic provinces surrounding Archaean cratonic nuclei in the East Antarctic Shield record two tectono-thermal episodes in late Mesoproterozoic and late Neoproterozoic-Cambrian times. In Western Dronning Maud Land, the high-grade Mesoproterozoic Maud Belt is juxtaposed against the Archaean Grunehogna Province and has traditionally been interpreted as a Grenvillian mobile belt that was thermally overprinted during the Early Palaeozoic. Integration of new U-Pb sensitive high-resolution ion microprobe and conventional single zircon and monazite age data, and Ar-Ar data on hornblende and biotite, with thermobarometric calculations on rocks from the H.U. Sverdrupfjella, northern Maud Belt, resulted in a more complex P-T-t evolution than previousyl assumed. A c. 540 Ma monazite, hosted by an upper ampibolite-facies mineral assemblage defining a regionally dominant top-to-NW shear fabric, provides strong evidence for the penetrative deformation in the area being of Pan-African age and not of Grenvillian age as previously reported. Relics of an eclogite-facies garnet-omphacite assemblage within strain-protected mafic boudins indicate that the peak metamorphic conditions recorded by most rocks in the area (T = 687-758°C, P = 9·4-11·3 kbar) were attained subsequent to decompression from P > 12·9 kbar. By analogy with limited U-Pb single zircon age data and on circumstantial textural grounds, this earlier eclogite-facies metamorphism is ascribed to subduction and accretion around 565 Ma. Post-peak metamorphic K-metasomatism under amphibolite-facies conditions is ascribed to the intrusion of post-orogenic granite at c. 480 Ma. The recognition of extensive Pan-African tectonism in the Maud Belt casts doubts on previous Rodinia reconstructions, in which this belt takes a pivotal position between East Antarctica, the Kalahari Craton and Laurentia. Evidence of late Mesoproterozoic high-grade metamorphism during the formation of the Maud Belt exists in the form of c. 1035 Ma zircon overgrowths that are probably related to relics of granulite-facies metamorphism recorded from other parts of the Maud Belt. The polymetamorphic rocks are largely derived from a c. 1140 Ma volcanic arc and 1072 ± 10 Ma granite. |
format |
Article in Journal/Newspaper |
author |
Board, W.S. Frimmel, H E Armstrong, Richard |
author_facet |
Board, W.S. Frimmel, H E Armstrong, Richard |
author_sort |
Board, W.S. |
title |
Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica |
title_short |
Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica |
title_full |
Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica |
title_fullStr |
Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica |
title_full_unstemmed |
Pan-African Tectonism in the Western Maud Belt: P-T-t Path for High-grade Gneisses in the H.U. Sverdrupfjella, East Antarctica |
title_sort |
pan-african tectonism in the western maud belt: p-t-t path for high-grade gneisses in the h.u. sverdrupfjella, east antarctica |
publisher |
Oxford University Press |
publishDate |
2015 |
url |
http://hdl.handle.net/1885/79206 |
long_lat |
ENVELOPE(-2.750,-2.750,-72.033,-72.033) ENVELOPE(12.000,12.000,-72.500,-72.500) ENVELOPE(0.583,0.583,-72.700,-72.700) |
geographic |
Antarctic Arctic Dronning Maud Land East Antarctica Grunehogna Queen Maud Land Sverdrupfjella |
geographic_facet |
Antarctic Arctic Dronning Maud Land East Antarctica Grunehogna Queen Maud Land Sverdrupfjella |
genre |
Antarc* Antarctic Antarctica Arctic Dronning Maud Land East Antarctica Queen Maud Land |
genre_facet |
Antarc* Antarctic Antarctica Arctic Dronning Maud Land East Antarctica Queen Maud Land |
op_source |
Journal of Petrology |
op_relation |
0022-3530 http://hdl.handle.net/1885/79206 |
_version_ |
1766264318117019648 |