Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt
A combined petrological and geochronological study was carried out on mafic granulites and associated felsic gneisses from the McKaskle Hills, eastern Amery Ice Shelf, East Antarctica. Garnet-bearing mafic granulites exhibit reaction textures and exsolution textures that indicate two-stage metamorph...
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fthighwire:oai:open-archive.highwire.org:petrology:48/8/1443 2023-05-15T13:22:06+02:00 Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt Liu, Xiaochun Zhao, Yue Zhao, Guochun Jian, Ping Xu, Gang 2007-08-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/48/8/1443 https://doi.org/10.1093/petrology/egm024 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/48/8/1443 http://dx.doi.org/10.1093/petrology/egm024 Copyright (C) 2007, Oxford University Press Original Papers TEXT 2007 fthighwire https://doi.org/10.1093/petrology/egm024 2013-05-27T22:45:27Z A combined petrological and geochronological study was carried out on mafic granulites and associated felsic gneisses from the McKaskle Hills, eastern Amery Ice Shelf, East Antarctica. Garnet-bearing mafic granulites exhibit reaction textures and exsolution textures that indicate two-stage metamorphic evolution. Thermobarometric estimates from matrix and symplectite assemblages yield peak and retrograde P – T conditions of 9·0–9·5 kbar and 880–950°C and 6·6–7·2 kbar and 700–750°C, respectively. Similar but slightly scattered peak P – T estimates of 7·9–10·1 kbar and 820–980°C are obtained from the core compositions of minerals from felsic para- and orthogneisses. Evidence for the prograde history is provided by muscovite inclusions in garnet from a paragneiss. Sensitive high-resolution ion microprobe U–Pb zircon dating reveals an evolutionary history for the granulites, including a mafic and felsic igneous intrusion at 1174–1019 Ma, sedimentation after 932–916 Ma, and a high-grade metamorphism at 533–529 Ma. In contrast, Sm–Nd mineral–whole-rock dating mainly yields a single age population at ∼500 Ma. This suggests that the McKaskle Hills form part of the Prydz Belt, and that the relatively high peak P – T conditions and a decompression-dominated P – T path for the rocks resulted from a single Cambrian metamorphic cycle, rather than two distinct metamorphic events as formerly inferred for the granulites from Prydz Bay. The age data also indicate that the Precambrian history of the McKaskle Hills is not only distinct from that of the early Neoproterozoic terrane in the northern Prince Charles Mountains, but also different from that of other parts of the Prydz Belt. The existence of multiple basement terranes, together with considerable crustal thickening followed by tectonic uplift and unroofing indicated by the clockwise P – T – t evolution, suggests that the Prydz Belt may represent a collisional orogen that resulted in the assembly of Gondwana during the Cambrian period. Text Amery Ice Shelf Antarc* Antarctica East Antarctica Ice Shelf Prince Charles Mountains Prydz Bay HighWire Press (Stanford University) Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) East Antarctica McKaskle Hills ENVELOPE(72.500,72.500,-70.000,-70.000) Prince Charles Mountains ENVELOPE(67.246,67.246,-71.427,-71.427) Prydz Bay Journal of Petrology 48 8 1443 1470 |
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Open Polar |
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HighWire Press (Stanford University) |
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fthighwire |
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English |
topic |
Original Papers |
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Original Papers Liu, Xiaochun Zhao, Yue Zhao, Guochun Jian, Ping Xu, Gang Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt |
topic_facet |
Original Papers |
description |
A combined petrological and geochronological study was carried out on mafic granulites and associated felsic gneisses from the McKaskle Hills, eastern Amery Ice Shelf, East Antarctica. Garnet-bearing mafic granulites exhibit reaction textures and exsolution textures that indicate two-stage metamorphic evolution. Thermobarometric estimates from matrix and symplectite assemblages yield peak and retrograde P – T conditions of 9·0–9·5 kbar and 880–950°C and 6·6–7·2 kbar and 700–750°C, respectively. Similar but slightly scattered peak P – T estimates of 7·9–10·1 kbar and 820–980°C are obtained from the core compositions of minerals from felsic para- and orthogneisses. Evidence for the prograde history is provided by muscovite inclusions in garnet from a paragneiss. Sensitive high-resolution ion microprobe U–Pb zircon dating reveals an evolutionary history for the granulites, including a mafic and felsic igneous intrusion at 1174–1019 Ma, sedimentation after 932–916 Ma, and a high-grade metamorphism at 533–529 Ma. In contrast, Sm–Nd mineral–whole-rock dating mainly yields a single age population at ∼500 Ma. This suggests that the McKaskle Hills form part of the Prydz Belt, and that the relatively high peak P – T conditions and a decompression-dominated P – T path for the rocks resulted from a single Cambrian metamorphic cycle, rather than two distinct metamorphic events as formerly inferred for the granulites from Prydz Bay. The age data also indicate that the Precambrian history of the McKaskle Hills is not only distinct from that of the early Neoproterozoic terrane in the northern Prince Charles Mountains, but also different from that of other parts of the Prydz Belt. The existence of multiple basement terranes, together with considerable crustal thickening followed by tectonic uplift and unroofing indicated by the clockwise P – T – t evolution, suggests that the Prydz Belt may represent a collisional orogen that resulted in the assembly of Gondwana during the Cambrian period. |
format |
Text |
author |
Liu, Xiaochun Zhao, Yue Zhao, Guochun Jian, Ping Xu, Gang |
author_facet |
Liu, Xiaochun Zhao, Yue Zhao, Guochun Jian, Ping Xu, Gang |
author_sort |
Liu, Xiaochun |
title |
Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt |
title_short |
Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt |
title_full |
Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt |
title_fullStr |
Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt |
title_full_unstemmed |
Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt |
title_sort |
petrology and geochronology of granulites from the mckaskle hills, eastern amery ice shelf, antarctica, and implications for the evolution of the prydz belt |
publisher |
Oxford University Press |
publishDate |
2007 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/48/8/1443 https://doi.org/10.1093/petrology/egm024 |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) ENVELOPE(72.500,72.500,-70.000,-70.000) ENVELOPE(67.246,67.246,-71.427,-71.427) |
geographic |
Amery Amery Ice Shelf East Antarctica McKaskle Hills Prince Charles Mountains Prydz Bay |
geographic_facet |
Amery Amery Ice Shelf East Antarctica McKaskle Hills Prince Charles Mountains Prydz Bay |
genre |
Amery Ice Shelf Antarc* Antarctica East Antarctica Ice Shelf Prince Charles Mountains Prydz Bay |
genre_facet |
Amery Ice Shelf Antarc* Antarctica East Antarctica Ice Shelf Prince Charles Mountains Prydz Bay |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/48/8/1443 http://dx.doi.org/10.1093/petrology/egm024 |
op_rights |
Copyright (C) 2007, Oxford University Press |
op_doi |
https://doi.org/10.1093/petrology/egm024 |
container_title |
Journal of Petrology |
container_volume |
48 |
container_issue |
8 |
container_start_page |
1443 |
op_container_end_page |
1470 |
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1766363272309637120 |