Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton
The nunataks of Heimefrontfjella in Dronning Maud Land (Antarctica) are dominantly composed of juvenile late Mesoproterozoic rocks that were metamorphosed and deformed at about 1080 and 500 Ma. Three discontinuity-bound terranes have been identified, namely the Kottas, Sivorg and Vardeklettane terra...
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/75420 2024-01-14T10:01:50+01:00 Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton Bauer, Wolfgang Jacobs, Jeffrey Bruce Fanning, Christopher Schmidt, R http://hdl.handle.net/1885/75420 unknown Elsevier 1342-937X http://hdl.handle.net/1885/75420 Gondwana Research Keywords: geochemistry geochronology metamorphic rock paleogeography petrography Proterozoic SHRIMP dating tectonic setting volcanism Antarctica East Antarctica Geochemistry Heimefrontfjella Late Mesoproterozoic Journal article ftanucanberra 2023-12-15T09:33:33Z The nunataks of Heimefrontfjella in Dronning Maud Land (Antarctica) are dominantly composed of juvenile late Mesoproterozoic rocks that were metamorphosed and deformed at about 1080 and 500 Ma. Three discontinuity-bound terranes have been identified, namely the Kottas, Sivorg and Vardeklettane terranes. In the Sivorg terrane the basement is mainly made up of fine-grained banded felsic and mafic gneisses, representing a metamorphosed bimodal volcanic sequence. In contrast, the basement in the Kottas terrane is composed of banded gneisses of tonalitic to dioritic composition and calc-alkaline metaplutonic rocks. The metamorphic rocks of the Vardeklettane terrane are granulites of supra- to infracrustal origin. Geochemical data characterize the protoliths of the bimodal sequence in the Sivorg terrane as tholeiitic basalts with MORB signature, alternating with high-k rhyolites derived from a highly fractionated granitic magma. Four U-Pb zircon SHRIMP ages prove a magmatic acrivity in the Sivorg terrane at least from ∼1160 to 1090 Ma. The orthogneisses from the Kottas terrane plot in the field of volcanic arc granites. Their protoliths may be derived from a calc-alkaline magmatic suite. According to recent reconstructions of the Kalahari continent the basement of the Kottas terrane is an Antarctic counterpart of the Mzumbe terrane in Natal. Our data allow a reconstruction of a subduction-related volcanic arc (Kottas Arc) along a southerly directed subduction zone which existed train ∼1200 to 1100 Ma, finally colliding with the southeastern margin of the Kaapvaal-Grunehogna craton. South of the volcanic arc, a back-arc basin (Sivorg terrane) developed during latest Mesoproterozoic times. Undeformed calc-alkaline granites in the northernmost Heimefrontfjella point to a final northward directed subduction of the oceanic lithosphere of the back-arc basin which led to the collision of the Coats Land block with the Kaapvaal-Grunehogna craton. Article in Journal/Newspaper Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Australian National University: ANU Digital Collections Antarctic East Antarctica Dronning Maud Land Coats Land ENVELOPE(-27.500,-27.500,-77.000,-77.000) Heimefrontfjella ENVELOPE(-11.000,-11.000,-74.667,-74.667) Grunehogna ENVELOPE(-2.750,-2.750,-72.033,-72.033) Vardeklettane ENVELOPE(-12.867,-12.867,-75.008,-75.008) |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
unknown |
topic |
Keywords: geochemistry geochronology metamorphic rock paleogeography petrography Proterozoic SHRIMP dating tectonic setting volcanism Antarctica East Antarctica Geochemistry Heimefrontfjella Late Mesoproterozoic |
spellingShingle |
Keywords: geochemistry geochronology metamorphic rock paleogeography petrography Proterozoic SHRIMP dating tectonic setting volcanism Antarctica East Antarctica Geochemistry Heimefrontfjella Late Mesoproterozoic Bauer, Wolfgang Jacobs, Jeffrey Bruce Fanning, Christopher Schmidt, R Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton |
topic_facet |
Keywords: geochemistry geochronology metamorphic rock paleogeography petrography Proterozoic SHRIMP dating tectonic setting volcanism Antarctica East Antarctica Geochemistry Heimefrontfjella Late Mesoproterozoic |
description |
The nunataks of Heimefrontfjella in Dronning Maud Land (Antarctica) are dominantly composed of juvenile late Mesoproterozoic rocks that were metamorphosed and deformed at about 1080 and 500 Ma. Three discontinuity-bound terranes have been identified, namely the Kottas, Sivorg and Vardeklettane terranes. In the Sivorg terrane the basement is mainly made up of fine-grained banded felsic and mafic gneisses, representing a metamorphosed bimodal volcanic sequence. In contrast, the basement in the Kottas terrane is composed of banded gneisses of tonalitic to dioritic composition and calc-alkaline metaplutonic rocks. The metamorphic rocks of the Vardeklettane terrane are granulites of supra- to infracrustal origin. Geochemical data characterize the protoliths of the bimodal sequence in the Sivorg terrane as tholeiitic basalts with MORB signature, alternating with high-k rhyolites derived from a highly fractionated granitic magma. Four U-Pb zircon SHRIMP ages prove a magmatic acrivity in the Sivorg terrane at least from ∼1160 to 1090 Ma. The orthogneisses from the Kottas terrane plot in the field of volcanic arc granites. Their protoliths may be derived from a calc-alkaline magmatic suite. According to recent reconstructions of the Kalahari continent the basement of the Kottas terrane is an Antarctic counterpart of the Mzumbe terrane in Natal. Our data allow a reconstruction of a subduction-related volcanic arc (Kottas Arc) along a southerly directed subduction zone which existed train ∼1200 to 1100 Ma, finally colliding with the southeastern margin of the Kaapvaal-Grunehogna craton. South of the volcanic arc, a back-arc basin (Sivorg terrane) developed during latest Mesoproterozoic times. Undeformed calc-alkaline granites in the northernmost Heimefrontfjella point to a final northward directed subduction of the oceanic lithosphere of the back-arc basin which led to the collision of the Coats Land block with the Kaapvaal-Grunehogna craton. |
format |
Article in Journal/Newspaper |
author |
Bauer, Wolfgang Jacobs, Jeffrey Bruce Fanning, Christopher Schmidt, R |
author_facet |
Bauer, Wolfgang Jacobs, Jeffrey Bruce Fanning, Christopher Schmidt, R |
author_sort |
Bauer, Wolfgang |
title |
Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton |
title_short |
Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton |
title_full |
Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton |
title_fullStr |
Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton |
title_full_unstemmed |
Late Mesoproterozoic Arc and Back-arc Volcanism in the Heimefrontfjella (East Antarctica) and Implications for the Palaeogeography at the Southeastern Margin of the Kaapvaal-Grunehogna Craton |
title_sort |
late mesoproterozoic arc and back-arc volcanism in the heimefrontfjella (east antarctica) and implications for the palaeogeography at the southeastern margin of the kaapvaal-grunehogna craton |
publisher |
Elsevier |
url |
http://hdl.handle.net/1885/75420 |
long_lat |
ENVELOPE(-27.500,-27.500,-77.000,-77.000) ENVELOPE(-11.000,-11.000,-74.667,-74.667) ENVELOPE(-2.750,-2.750,-72.033,-72.033) ENVELOPE(-12.867,-12.867,-75.008,-75.008) |
geographic |
Antarctic East Antarctica Dronning Maud Land Coats Land Heimefrontfjella Grunehogna Vardeklettane |
geographic_facet |
Antarctic East Antarctica Dronning Maud Land Coats Land Heimefrontfjella Grunehogna Vardeklettane |
genre |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica |
op_source |
Gondwana Research |
op_relation |
1342-937X http://hdl.handle.net/1885/75420 |
_version_ |
1788056558443167744 |