U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex
Ion microprobe U-Pb zircon geochronology of an orthopyroxene-bearing felsic orthogneiss from central Tonagh Island, Enderby Land, East Antarctica provides insight into the chronological-metamorphic evolution of the Archaean Napier Complex, the details of which have been the source of debate for over...
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Language: | English |
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2002
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Online Access: | https://hdl.handle.net/1983/fc98788c-f6ac-406f-9515-7a34b6725371 https://research-information.bris.ac.uk/en/publications/fc98788c-f6ac-406f-9515-7a34b6725371 https://doi.org/10.1016/S0301-9268(02)00023-2 http://www.scopus.com/inward/record.url?scp=0037096353&partnerID=8YFLogxK |
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ftubristolcris:oai:research-information.bris.ac.uk:publications/fc98788c-f6ac-406f-9515-7a34b6725371 2024-02-11T09:57:23+01:00 U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex Carson, C. J. Ague, J. J. Coath, C. D. 2002-06-15 https://hdl.handle.net/1983/fc98788c-f6ac-406f-9515-7a34b6725371 https://research-information.bris.ac.uk/en/publications/fc98788c-f6ac-406f-9515-7a34b6725371 https://doi.org/10.1016/S0301-9268(02)00023-2 http://www.scopus.com/inward/record.url?scp=0037096353&partnerID=8YFLogxK eng eng info:eu-repo/semantics/restrictedAccess Carson , C J , Ague , J J & Coath , C D 2002 , ' U-Pb geochronology from Tonagh Island, East Antarctica : Implications for the timing of ultra-high temperature metamorphism of the Napier Complex ' , Precambrian Research , vol. 116 , no. 3-4 , pp. 237-263 . https://doi.org/10.1016/S0301-9268(02)00023-2 East Antarctica Ion probe Napier Complex U-Pb geochronology Zircon article 2002 ftubristolcris https://doi.org/10.1016/S0301-9268(02)00023-2 2024-01-25T23:28:58Z Ion microprobe U-Pb zircon geochronology of an orthopyroxene-bearing felsic orthogneiss from central Tonagh Island, Enderby Land, East Antarctica provides insight into the chronological-metamorphic evolution of the Archaean Napier Complex, the details of which have been the source of debate for over two decades. The orthogneiss crystallised at 2626 ± 28 Ma, predating peak, ultra-high temperature (UHT) metamorphism and development of an intense regional S 1 gneissosity. Two subsequent episodes of zircon growth/resetting can be identified. A minor period of zircon growth occurred at 2546 ± 13 Ma, the regional significance and geological nature of which is unclear. This was followed by an episode of abundant zircon growth, as mantles on ∼ 2626 Ma cores and as anhedral grains, partly characterised by high Th/U (> 1.2), at ∼ 2450-2480 Ma. This age coincides with both lower and upper concordia intercept ages from other U-Pb zircon studies, and several Rb-Sr and Sm-Nd whole-rock isochron ages from the Napier Complex. We conclude that UHT metamorphism occurred at ∼ 2450-2480 Ma, and find no compelling evidence that UHT occurred much earlier as has been postulated. The zircon U-Pb data from this study also indicates a lower intercept age of ∼ 500 Ma, which coincides with the emplacement of Early Palaeozoic pegmatite swarms and synchronous infiltration of aqueous fluids into the southwestern regions of the Napier Complex. Article in Journal/Newspaper Antarc* Antarctica East Antarctica Enderby Land Tonagh Island University of Bristol: Bristol Research East Antarctica Napier ENVELOPE(-58.440,-58.440,-62.167,-62.167) Tonagh Island ENVELOPE(50.333,50.333,-67.117,-67.117) Precambrian Research 116 3-4 237 263 |
institution |
Open Polar |
collection |
University of Bristol: Bristol Research |
op_collection_id |
ftubristolcris |
language |
English |
topic |
East Antarctica Ion probe Napier Complex U-Pb geochronology Zircon |
spellingShingle |
East Antarctica Ion probe Napier Complex U-Pb geochronology Zircon Carson, C. J. Ague, J. J. Coath, C. D. U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex |
topic_facet |
East Antarctica Ion probe Napier Complex U-Pb geochronology Zircon |
description |
Ion microprobe U-Pb zircon geochronology of an orthopyroxene-bearing felsic orthogneiss from central Tonagh Island, Enderby Land, East Antarctica provides insight into the chronological-metamorphic evolution of the Archaean Napier Complex, the details of which have been the source of debate for over two decades. The orthogneiss crystallised at 2626 ± 28 Ma, predating peak, ultra-high temperature (UHT) metamorphism and development of an intense regional S 1 gneissosity. Two subsequent episodes of zircon growth/resetting can be identified. A minor period of zircon growth occurred at 2546 ± 13 Ma, the regional significance and geological nature of which is unclear. This was followed by an episode of abundant zircon growth, as mantles on ∼ 2626 Ma cores and as anhedral grains, partly characterised by high Th/U (> 1.2), at ∼ 2450-2480 Ma. This age coincides with both lower and upper concordia intercept ages from other U-Pb zircon studies, and several Rb-Sr and Sm-Nd whole-rock isochron ages from the Napier Complex. We conclude that UHT metamorphism occurred at ∼ 2450-2480 Ma, and find no compelling evidence that UHT occurred much earlier as has been postulated. The zircon U-Pb data from this study also indicates a lower intercept age of ∼ 500 Ma, which coincides with the emplacement of Early Palaeozoic pegmatite swarms and synchronous infiltration of aqueous fluids into the southwestern regions of the Napier Complex. |
format |
Article in Journal/Newspaper |
author |
Carson, C. J. Ague, J. J. Coath, C. D. |
author_facet |
Carson, C. J. Ague, J. J. Coath, C. D. |
author_sort |
Carson, C. J. |
title |
U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex |
title_short |
U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex |
title_full |
U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex |
title_fullStr |
U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex |
title_full_unstemmed |
U-Pb geochronology from Tonagh Island, East Antarctica:Implications for the timing of ultra-high temperature metamorphism of the Napier Complex |
title_sort |
u-pb geochronology from tonagh island, east antarctica:implications for the timing of ultra-high temperature metamorphism of the napier complex |
publishDate |
2002 |
url |
https://hdl.handle.net/1983/fc98788c-f6ac-406f-9515-7a34b6725371 https://research-information.bris.ac.uk/en/publications/fc98788c-f6ac-406f-9515-7a34b6725371 https://doi.org/10.1016/S0301-9268(02)00023-2 http://www.scopus.com/inward/record.url?scp=0037096353&partnerID=8YFLogxK |
long_lat |
ENVELOPE(-58.440,-58.440,-62.167,-62.167) ENVELOPE(50.333,50.333,-67.117,-67.117) |
geographic |
East Antarctica Napier Tonagh Island |
geographic_facet |
East Antarctica Napier Tonagh Island |
genre |
Antarc* Antarctica East Antarctica Enderby Land Tonagh Island |
genre_facet |
Antarc* Antarctica East Antarctica Enderby Land Tonagh Island |
op_source |
Carson , C J , Ague , J J & Coath , C D 2002 , ' U-Pb geochronology from Tonagh Island, East Antarctica : Implications for the timing of ultra-high temperature metamorphism of the Napier Complex ' , Precambrian Research , vol. 116 , no. 3-4 , pp. 237-263 . https://doi.org/10.1016/S0301-9268(02)00023-2 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/S0301-9268(02)00023-2 |
container_title |
Precambrian Research |
container_volume |
116 |
container_issue |
3-4 |
container_start_page |
237 |
op_container_end_page |
263 |
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1790609683129565184 |