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Article: Petrology and geochronology of granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and implications for the evolution of the Prydz Belt

TitlePetrology and geochronology of granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and implications for the evolution of the Prydz Belt
Authors
KeywordsCambrian metamorphism
East Antarctica
Mesoproterozoic basement
P-T path
Prydz Belt
Issue Date2007
PublisherOxford University Press. The Journal's web site is located at http://petrology.oxfordjournals.org/
Citation
Journal Of Petrology, 2007, v. 48 n. 8, p. 1443-1470 How to Cite?
AbstractA 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. © The Author 2007. Published by Oxford University Press. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/72993
ISSN
2015 Impact Factor: 3.768
2015 SCImago Journal Rankings: 2.992
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLiu, Xen_HK
dc.contributor.authorZhao, Yen_HK
dc.contributor.authorZhao, Gen_HK
dc.contributor.authorJian, Pen_HK
dc.contributor.authorXu, Gen_HK
dc.date.accessioned2010-09-06T06:47:02Z-
dc.date.available2010-09-06T06:47:02Z-
dc.date.issued2007en_HK
dc.identifier.citationJournal Of Petrology, 2007, v. 48 n. 8, p. 1443-1470en_HK
dc.identifier.issn0022-3530en_HK
dc.identifier.urihttp://hdl.handle.net/10722/72993-
dc.description.abstractA 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. © The Author 2007. Published by Oxford University Press. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherOxford University Press. The Journal's web site is located at http://petrology.oxfordjournals.org/en_HK
dc.relation.ispartofJournal of Petrologyen_HK
dc.rightsJournal of Petrology. Copyright © Oxford University Press.en_HK
dc.subjectCambrian metamorphismen_HK
dc.subjectEast Antarcticaen_HK
dc.subjectMesoproterozoic basementen_HK
dc.subjectP-T pathen_HK
dc.subjectPrydz Belten_HK
dc.titlePetrology and geochronology of granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and implications for the evolution of the Prydz Belten_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-3530&volume=48&spage=1443&epage=1470&date=2007&atitle=Petrology+and+geochronology+of+granulites+from+the+McKaskle+Hills,+Eastern+Amery+Ice+Shelf,+Antarctica,+and+implications+for+the+evolution+of+the+Prydz+Belten_HK
dc.identifier.emailZhao, G:gzhao@hkucc.hku.hken_HK
dc.identifier.authorityZhao, G=rp00842en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1093/petrology/egm024en_HK
dc.identifier.scopuseid_2-s2.0-34547805979en_HK
dc.identifier.hkuros144324en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-34547805979&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume48en_HK
dc.identifier.issue8en_HK
dc.identifier.spage1443en_HK
dc.identifier.epage1470en_HK
dc.identifier.isiWOS:000248148700001-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridLiu, X=7409282590en_HK
dc.identifier.scopusauthoridZhao, Y=33768195200en_HK
dc.identifier.scopusauthoridZhao, G=7403296321en_HK
dc.identifier.scopusauthoridJian, P=7003645708en_HK
dc.identifier.scopusauthoridXu, G=36038689100en_HK

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