Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology
40Ar/39Ar and U–Pb data from five structural domains constrain the late Neoproterozoic – early Palaeozoic tectonothermal history of the eastern part of the East African–Antarctic Orogen in Sør Rondane. A total of 27 new Ar/Ar ages span 570–474 Ma, roughly corresponding to the age range of three gene...
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Online Access: | https://hdl.handle.net/11250/2756540 https://doi.org/10.1017/S0016756820000746 |
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ftunivbergen:oai:bora.uib.no:11250/2756540 2023-05-15T13:40:58+02:00 Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology Ruppel, Antonia S. Jacobs, Joachim Läufer, Andreas Ratschbacher, Lothar 2020 application/pdf https://hdl.handle.net/11250/2756540 https://doi.org/10.1017/S0016756820000746 eng eng Cambridge University Press urn:issn:0016-7568 https://hdl.handle.net/11250/2756540 https://doi.org/10.1017/S0016756820000746 cristin:1873576 Geological Magazine. 2020 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2020 The Authors Geological Magazine Journal article Peer reviewed 2020 ftunivbergen https://doi.org/10.1017/S0016756820000746 2023-03-14T17:44:46Z 40Ar/39Ar and U–Pb data from five structural domains constrain the late Neoproterozoic – early Palaeozoic tectonothermal history of the eastern part of the East African–Antarctic Orogen in Sør Rondane. A total of 27 new Ar/Ar ages span 570–474 Ma, roughly corresponding to the age range of three generations of syn- to post-tectonic granitoids. The ages are distinct for the five structural domains. The oldest cooling ages come from the weakly deformed southern part of the SW Terrane of Sør Rondane (SW Terrane S), a sliver of a Tonian island arc, which escaped much of the late Neoproterozoic accretionary deformation. This terrane was intruded by the oldest and largest granitoid complex at c. 640–620 Ma. The oldest Ar/Ar amphibole and biotite ages of 570–524 Ma are from the Main Shear Zone, along the northern margin of the SW Terrane S sliver. It hosts granites of age c. 584–570 Ma strung out along the shear zone. Two younger granitoid phases are recorded in the adjacent four terranes to the west, north and east of the SW Terrane S, and correlate with the younger group of Ar/Ar biotite ages spanning 513–474 Ma. We interpret the magmatic and cooling history of duration > 150 Ma to reflect repeated phases of accretion, magmatism and reactivation, that is, collage-style tectonism, partly pre-dating the incorporation of Sør Rondane into Gondwana. The study area first accreted to the cryptic Valkyrie Craton in Tonian times, was then ‘sandwiched’ between the Kalahari and Indo-Antarctica cratons, and experienced extensional tectonics and elevated heat flux due to lithospheric delamination, which resulted in slow cooling during the Pan-African Orogeny. publishedVersion Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica University of Bergen: Bergen Open Research Archive (BORA-UiB) Antarctic East Antarctica Sør-Rondane ENVELOPE(25.000,25.000,-72.000,-72.000) Valkyrie ENVELOPE(162.317,162.317,-77.550,-77.550) Geological Magazine 158 4 635 655 |
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Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
40Ar/39Ar and U–Pb data from five structural domains constrain the late Neoproterozoic – early Palaeozoic tectonothermal history of the eastern part of the East African–Antarctic Orogen in Sør Rondane. A total of 27 new Ar/Ar ages span 570–474 Ma, roughly corresponding to the age range of three generations of syn- to post-tectonic granitoids. The ages are distinct for the five structural domains. The oldest cooling ages come from the weakly deformed southern part of the SW Terrane of Sør Rondane (SW Terrane S), a sliver of a Tonian island arc, which escaped much of the late Neoproterozoic accretionary deformation. This terrane was intruded by the oldest and largest granitoid complex at c. 640–620 Ma. The oldest Ar/Ar amphibole and biotite ages of 570–524 Ma are from the Main Shear Zone, along the northern margin of the SW Terrane S sliver. It hosts granites of age c. 584–570 Ma strung out along the shear zone. Two younger granitoid phases are recorded in the adjacent four terranes to the west, north and east of the SW Terrane S, and correlate with the younger group of Ar/Ar biotite ages spanning 513–474 Ma. We interpret the magmatic and cooling history of duration > 150 Ma to reflect repeated phases of accretion, magmatism and reactivation, that is, collage-style tectonism, partly pre-dating the incorporation of Sør Rondane into Gondwana. The study area first accreted to the cryptic Valkyrie Craton in Tonian times, was then ‘sandwiched’ between the Kalahari and Indo-Antarctica cratons, and experienced extensional tectonics and elevated heat flux due to lithospheric delamination, which resulted in slow cooling during the Pan-African Orogeny. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Ruppel, Antonia S. Jacobs, Joachim Läufer, Andreas Ratschbacher, Lothar |
spellingShingle |
Ruppel, Antonia S. Jacobs, Joachim Läufer, Andreas Ratschbacher, Lothar Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology |
author_facet |
Ruppel, Antonia S. Jacobs, Joachim Läufer, Andreas Ratschbacher, Lothar |
author_sort |
Ruppel, Antonia S. |
title |
Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology |
title_short |
Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology |
title_full |
Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology |
title_fullStr |
Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology |
title_full_unstemmed |
Protracted late Neoproterozic – early Palaeozoic deformation and cooling history of Sør Rondane, East Antarctica, from 40Ar/39Ar and U–Pb geochronology |
title_sort |
protracted late neoproterozic – early palaeozoic deformation and cooling history of sør rondane, east antarctica, from 40ar/39ar and u–pb geochronology |
publisher |
Cambridge University Press |
publishDate |
2020 |
url |
https://hdl.handle.net/11250/2756540 https://doi.org/10.1017/S0016756820000746 |
long_lat |
ENVELOPE(25.000,25.000,-72.000,-72.000) ENVELOPE(162.317,162.317,-77.550,-77.550) |
geographic |
Antarctic East Antarctica Sør-Rondane Valkyrie |
geographic_facet |
Antarctic East Antarctica Sør-Rondane Valkyrie |
genre |
Antarc* Antarctic Antarctica East Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica |
op_source |
Geological Magazine |
op_relation |
urn:issn:0016-7568 https://hdl.handle.net/11250/2756540 https://doi.org/10.1017/S0016756820000746 cristin:1873576 Geological Magazine. 2020 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2020 The Authors |
op_doi |
https://doi.org/10.1017/S0016756820000746 |
container_title |
Geological Magazine |
container_volume |
158 |
container_issue |
4 |
container_start_page |
635 |
op_container_end_page |
655 |
_version_ |
1766143907325804544 |