Anatomy of the Kuunga Orogen in East Antarctica
The Kuunga Orogen in East Antarctica essentially lies buried below the ice sheet, and therefore remains the most poorly exposed and enigmatic Gondwana-forming orogen. Paleomagnetic constraints from India and Australia imply that a Neoproterozoic plate boundary bisecting East Antarctica accommodated...
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ftunivtasecite:oai:ecite.utas.edu.au:131214 2023-05-15T13:55:18+02:00 Anatomy of the Kuunga Orogen in East Antarctica Halpin, J Daczko, N Fitzsimons, I Whittaker, J Mulder, J 2018 application/pdf http://agcc.org.au/ http://ecite.utas.edu.au/131214 en eng . http://ecite.utas.edu.au/131214/1/AGCC_abstracts 473_Halpin2018.pdf Halpin, J and Daczko, N and Fitzsimons, I and Whittaker, J and Mulder, J, Anatomy of the Kuunga Orogen in East Antarctica, Australian Geoscience Council Convention Abstracts, 14-18 October 2018, Adelaide, South Australia, pp. 473. (2018) [Conference Extract] http://ecite.utas.edu.au/131214 Earth Sciences Geology Geochronology Conference Extract NonPeerReviewed 2018 ftunivtasecite 2019-12-13T22:29:08Z The Kuunga Orogen in East Antarctica essentially lies buried below the ice sheet, and therefore remains the most poorly exposed and enigmatic Gondwana-forming orogen. Paleomagnetic constraints from India and Australia imply that a Neoproterozoic plate boundary bisecting East Antarctica accommodated some 3000-5000 km of relative plate motion. However, evidence for typical plate boundary processes in the Antarctic geological record (e.g., arc/subduction-related magmatism, high-P metamorphism) during this time remains equivocal. Here we explore the spatial extent and timing of Neoproterozoic-Cambrian tectonics associated with the amalgamation of eastern Gondwana using new and published geological datasets. We suggest the boundary between crust originally of Indian and Australian affinity can be resolved into two plate-boundary segments in East Antarctica, representing two contrasting tectonic regimes: (1) a strike-slip/transpressional margin delineated by a series of NNW-trending lineaments in Queen Mary-Wilhelm II-Wilkes lands, and (2) a near-orthogonal convergent margin that consumed the Mawson Ocean basin, now recorded by significantly thickened (60 km) crust and lithosphere (200 km) through the Antarctic interior, incorporating the Gamburtsev Subglacial Mountains region. We suggest that, based on key changes in Hf-isotopic character of detrital zircon, cryptic Neoproterozoic arc magmatism in the interior of Antarctica commenced from c. 720 Ma, continent-continent collision was underway by c. 620-600 Ma, and that the plethora of c. 550-500 Ma U-Pb ages mostly mark the final stages of collision, slab break-off failure and orogenic collapse. These new constraints provide an opportunity for improved plate models for the Neoproterozoic and the transition from the supercontinent Rodinia to Gondwana. Conference Object Antarc* Antarctic Antarctica East Antarctica Ice Sheet eCite UTAS (University of Tasmania) Antarctic The Antarctic East Antarctica Indian Gamburtsev Subglacial Mountains ENVELOPE(76.000,76.000,-80.500,-80.500) |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Geology Geochronology |
spellingShingle |
Earth Sciences Geology Geochronology Halpin, J Daczko, N Fitzsimons, I Whittaker, J Mulder, J Anatomy of the Kuunga Orogen in East Antarctica |
topic_facet |
Earth Sciences Geology Geochronology |
description |
The Kuunga Orogen in East Antarctica essentially lies buried below the ice sheet, and therefore remains the most poorly exposed and enigmatic Gondwana-forming orogen. Paleomagnetic constraints from India and Australia imply that a Neoproterozoic plate boundary bisecting East Antarctica accommodated some 3000-5000 km of relative plate motion. However, evidence for typical plate boundary processes in the Antarctic geological record (e.g., arc/subduction-related magmatism, high-P metamorphism) during this time remains equivocal. Here we explore the spatial extent and timing of Neoproterozoic-Cambrian tectonics associated with the amalgamation of eastern Gondwana using new and published geological datasets. We suggest the boundary between crust originally of Indian and Australian affinity can be resolved into two plate-boundary segments in East Antarctica, representing two contrasting tectonic regimes: (1) a strike-slip/transpressional margin delineated by a series of NNW-trending lineaments in Queen Mary-Wilhelm II-Wilkes lands, and (2) a near-orthogonal convergent margin that consumed the Mawson Ocean basin, now recorded by significantly thickened (60 km) crust and lithosphere (200 km) through the Antarctic interior, incorporating the Gamburtsev Subglacial Mountains region. We suggest that, based on key changes in Hf-isotopic character of detrital zircon, cryptic Neoproterozoic arc magmatism in the interior of Antarctica commenced from c. 720 Ma, continent-continent collision was underway by c. 620-600 Ma, and that the plethora of c. 550-500 Ma U-Pb ages mostly mark the final stages of collision, slab break-off failure and orogenic collapse. These new constraints provide an opportunity for improved plate models for the Neoproterozoic and the transition from the supercontinent Rodinia to Gondwana. |
format |
Conference Object |
author |
Halpin, J Daczko, N Fitzsimons, I Whittaker, J Mulder, J |
author_facet |
Halpin, J Daczko, N Fitzsimons, I Whittaker, J Mulder, J |
author_sort |
Halpin, J |
title |
Anatomy of the Kuunga Orogen in East Antarctica |
title_short |
Anatomy of the Kuunga Orogen in East Antarctica |
title_full |
Anatomy of the Kuunga Orogen in East Antarctica |
title_fullStr |
Anatomy of the Kuunga Orogen in East Antarctica |
title_full_unstemmed |
Anatomy of the Kuunga Orogen in East Antarctica |
title_sort |
anatomy of the kuunga orogen in east antarctica |
publisher |
. |
publishDate |
2018 |
url |
http://agcc.org.au/ http://ecite.utas.edu.au/131214 |
long_lat |
ENVELOPE(76.000,76.000,-80.500,-80.500) |
geographic |
Antarctic The Antarctic East Antarctica Indian Gamburtsev Subglacial Mountains |
geographic_facet |
Antarctic The Antarctic East Antarctica Indian Gamburtsev Subglacial Mountains |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet |
op_relation |
http://ecite.utas.edu.au/131214/1/AGCC_abstracts 473_Halpin2018.pdf Halpin, J and Daczko, N and Fitzsimons, I and Whittaker, J and Mulder, J, Anatomy of the Kuunga Orogen in East Antarctica, Australian Geoscience Council Convention Abstracts, 14-18 October 2018, Adelaide, South Australia, pp. 473. (2018) [Conference Extract] http://ecite.utas.edu.au/131214 |
_version_ |
1766261698208989184 |