Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes
The assembly of eastern Gondwana involved the amalgamation of Indo-Antarctica and Australo-Antarctica along the Kuunga orogen. The location of the suture or sutures between Indo-Antarctica and Australo-Antarctica within the Kuunga orogen remains debated as key geological relationships are concealed...
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ftunivtasecite:oai:ecite.utas.edu.au:131213 2023-05-15T13:55:18+02:00 Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes Mulder, J Halpin, J Daczko, N Meffre, S Orth, K Thompson, J Morrissey, L 2018 application/pdf http://agcc.org.au/ http://ecite.utas.edu.au/131213 en eng . http://ecite.utas.edu.au/131213/1/AGCC_abstracts 362_Mulder2018.pdf Mulder, J and Halpin, J and Daczko, N and Meffre, S and Orth, K and Thompson, J and Morrissey, L, Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes, Australian Geoscience Council Convention Abstracts, 14-18 October 2018, Adelaide, South Australia, pp. 362. (2018) [Conference Extract] http://ecite.utas.edu.au/131213 Earth Sciences Geology Geochronology Conference Extract NonPeerReviewed 2018 ftunivtasecite 2019-12-13T22:29:08Z The assembly of eastern Gondwana involved the amalgamation of Indo-Antarctica and Australo-Antarctica along the Kuunga orogen. The location of the suture or sutures between Indo-Antarctica and Australo-Antarctica within the Kuunga orogen remains debated as key geological relationships are concealed beneath ice. The most recent interpretation identifies the Mirny Fault as a key suture between crust of Indo-Antarctic and Australo-Antarctic affinity. However, sparse exposure of bedrock in this region precludes traditional geological characterisation of the crust on both sides this structure. Here, we test the Mirny Fault as a key suture between Indo-Antarctica and Australo-Antarctica using Pb isotopes of detrital feldspars from offshore sediments referenced to new and compiled feldspar Pb isotopic data from onshore exposures of Indo-Antarctica and Australo-Antarctica. The feldspar Pb-isotope signature of Indo-Antarctica forms a broad population with ⁰⁷Pb/⁰⁴Pb ratios of 15.516.1 and ⁰⁶Pb/⁰⁴Pb of 1719. In contrast, Australo-Antarctica has a feldspar Pb-isotope signature characterised by a tight cluster of ⁰⁷Pb/⁰⁴Pb (15.515.8) and ⁰⁶Pb/⁰⁴Pb (16.517) ratios, which is distinct from Indo-Antarctica. Locally-derived Holocene sediments offshore of the Mirny region contain detrital feldspars with Pb-isotope compositions recording a contribution from both Indo-Antarctica and Australo-Antarctica. The presence of Australo-Antarctic and Indo-Antarctic crust near the Mirny Fault supports the interpretation of this structure as a fundamental terrane boundary. We interpret the Mirny Fault as the key suture between Indo-Antarctica and Australo-Antarctica and trace this boundary into the interior of East Antarctica to connect with an inferred Gondwanan-aged suture within the Gamburtsev Subglacial Mountains. Conference Object Antarc* Antarctic Antarctica East Antarctica eCite UTAS (University of Tasmania) Antarctic East Antarctica Gamburtsev Subglacial Mountains ENVELOPE(76.000,76.000,-80.500,-80.500) Mirny ENVELOPE(93.009,93.009,-66.553,-66.553) |
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Open Polar |
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eCite UTAS (University of Tasmania) |
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ftunivtasecite |
language |
English |
topic |
Earth Sciences Geology Geochronology |
spellingShingle |
Earth Sciences Geology Geochronology Mulder, J Halpin, J Daczko, N Meffre, S Orth, K Thompson, J Morrissey, L Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes |
topic_facet |
Earth Sciences Geology Geochronology |
description |
The assembly of eastern Gondwana involved the amalgamation of Indo-Antarctica and Australo-Antarctica along the Kuunga orogen. The location of the suture or sutures between Indo-Antarctica and Australo-Antarctica within the Kuunga orogen remains debated as key geological relationships are concealed beneath ice. The most recent interpretation identifies the Mirny Fault as a key suture between crust of Indo-Antarctic and Australo-Antarctic affinity. However, sparse exposure of bedrock in this region precludes traditional geological characterisation of the crust on both sides this structure. Here, we test the Mirny Fault as a key suture between Indo-Antarctica and Australo-Antarctica using Pb isotopes of detrital feldspars from offshore sediments referenced to new and compiled feldspar Pb isotopic data from onshore exposures of Indo-Antarctica and Australo-Antarctica. The feldspar Pb-isotope signature of Indo-Antarctica forms a broad population with ⁰⁷Pb/⁰⁴Pb ratios of 15.516.1 and ⁰⁶Pb/⁰⁴Pb of 1719. In contrast, Australo-Antarctica has a feldspar Pb-isotope signature characterised by a tight cluster of ⁰⁷Pb/⁰⁴Pb (15.515.8) and ⁰⁶Pb/⁰⁴Pb (16.517) ratios, which is distinct from Indo-Antarctica. Locally-derived Holocene sediments offshore of the Mirny region contain detrital feldspars with Pb-isotope compositions recording a contribution from both Indo-Antarctica and Australo-Antarctica. The presence of Australo-Antarctic and Indo-Antarctic crust near the Mirny Fault supports the interpretation of this structure as a fundamental terrane boundary. We interpret the Mirny Fault as the key suture between Indo-Antarctica and Australo-Antarctica and trace this boundary into the interior of East Antarctica to connect with an inferred Gondwanan-aged suture within the Gamburtsev Subglacial Mountains. |
format |
Conference Object |
author |
Mulder, J Halpin, J Daczko, N Meffre, S Orth, K Thompson, J Morrissey, L |
author_facet |
Mulder, J Halpin, J Daczko, N Meffre, S Orth, K Thompson, J Morrissey, L |
author_sort |
Mulder, J |
title |
Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes |
title_short |
Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes |
title_full |
Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes |
title_fullStr |
Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes |
title_full_unstemmed |
Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes |
title_sort |
locating hidden terrane boundaries in east antarctica with detrital feldspar pb isotopes |
publisher |
. |
publishDate |
2018 |
url |
http://agcc.org.au/ http://ecite.utas.edu.au/131213 |
long_lat |
ENVELOPE(76.000,76.000,-80.500,-80.500) ENVELOPE(93.009,93.009,-66.553,-66.553) |
geographic |
Antarctic East Antarctica Gamburtsev Subglacial Mountains Mirny |
geographic_facet |
Antarctic East Antarctica Gamburtsev Subglacial Mountains Mirny |
genre |
Antarc* Antarctic Antarctica East Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica |
op_relation |
http://ecite.utas.edu.au/131213/1/AGCC_abstracts 362_Mulder2018.pdf Mulder, J and Halpin, J and Daczko, N and Meffre, S and Orth, K and Thompson, J and Morrissey, L, Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes, Australian Geoscience Council Convention Abstracts, 14-18 October 2018, Adelaide, South Australia, pp. 362. (2018) [Conference Extract] http://ecite.utas.edu.au/131213 |
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1766261698037022720 |