A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen
The East African–Antarctic orogen is one of the largest orogenic belts on the planet. It resulted from the collision of various parts of proto–East and West Gondwana during late Neoproterozoic–early Paleozoic time (between 650 and 500 Ma). We propose that the southern part of this Himalayan-type oro...
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ftnerc:oai:nora.nerc.ac.uk:5586 2024-06-09T07:40:08+00:00 A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen Jacobs, J. Thomas, Robert James 2004 http://nora.nerc.ac.uk/id/eprint/5586/ http://geology.geoscienceworld.org/content/vol31/issue8/ unknown Geological Society of America Jacobs, J.; Thomas, Robert James. 2004 A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen. Geology, 32 (8). 721-724. https://doi.org/10.1130/G20516.1 <https://doi.org/10.1130/G20516.1> Earth Sciences Publication - Article PeerReviewed 2004 ftnerc https://doi.org/10.1130/G20516.1 2024-05-15T08:49:44Z The East African–Antarctic orogen is one of the largest orogenic belts on the planet. It resulted from the collision of various parts of proto–East and West Gondwana during late Neoproterozoic–early Paleozoic time (between 650 and 500 Ma). We propose that the southern part of this Himalayan-type orogen can be interpreted in terms of a lateral-escape tectonic model. Modern Gondwana reconstructions show that the southern part of the East African– Antarctic orogen can best be reassembled when a number of microplates (the Falkland, Ellsworth-Haag, and Filchner blocks) are positioned between southern Africa and East Antarctica. This microplate assemblage is unusual. The microplates probably represent shear-zone–bounded blocks, produced by tectonic translation during lateral escape, similar to those currently evolving in Southeast Asia. One of the escape-related shear zones is exposed as the 20-km-wide Heimefront transpression zone in western Dronning Maud Land. Coats Land, a crustal block within the orogen, probably represents a block of older crust that was not subjected to tectonometamorphic reworking ca. 500 Ma by lateral tectonic escape. The southern part of the orogen is also typified by very large volumes of late-tectonic A2-type granitoids, intruded ca. 530–490 Ma, probably as a consequence of delamination of the orogenic root and the subsequent influx of hot asthenospheric mantle during tectonic escape. Erosional unroofing of the orogen is documented by the remnants of originally massive areas covered by Cambrian– Ordovician molasse-type sedimentary rocks throughout Africa, Arabia, and Antarctica, testifying to the past extent and size of this largest of orogens. Article in Journal/Newspaper Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Natural Environment Research Council: NERC Open Research Archive Antarctic East Antarctica Dronning Maud Land Coats Land ENVELOPE(-27.500,-27.500,-77.000,-77.000) Haag ENVELOPE(-79.000,-79.000,-77.667,-77.667) Geology 32 8 721 |
institution |
Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Jacobs, J. Thomas, Robert James A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen |
topic_facet |
Earth Sciences |
description |
The East African–Antarctic orogen is one of the largest orogenic belts on the planet. It resulted from the collision of various parts of proto–East and West Gondwana during late Neoproterozoic–early Paleozoic time (between 650 and 500 Ma). We propose that the southern part of this Himalayan-type orogen can be interpreted in terms of a lateral-escape tectonic model. Modern Gondwana reconstructions show that the southern part of the East African– Antarctic orogen can best be reassembled when a number of microplates (the Falkland, Ellsworth-Haag, and Filchner blocks) are positioned between southern Africa and East Antarctica. This microplate assemblage is unusual. The microplates probably represent shear-zone–bounded blocks, produced by tectonic translation during lateral escape, similar to those currently evolving in Southeast Asia. One of the escape-related shear zones is exposed as the 20-km-wide Heimefront transpression zone in western Dronning Maud Land. Coats Land, a crustal block within the orogen, probably represents a block of older crust that was not subjected to tectonometamorphic reworking ca. 500 Ma by lateral tectonic escape. The southern part of the orogen is also typified by very large volumes of late-tectonic A2-type granitoids, intruded ca. 530–490 Ma, probably as a consequence of delamination of the orogenic root and the subsequent influx of hot asthenospheric mantle during tectonic escape. Erosional unroofing of the orogen is documented by the remnants of originally massive areas covered by Cambrian– Ordovician molasse-type sedimentary rocks throughout Africa, Arabia, and Antarctica, testifying to the past extent and size of this largest of orogens. |
format |
Article in Journal/Newspaper |
author |
Jacobs, J. Thomas, Robert James |
author_facet |
Jacobs, J. Thomas, Robert James |
author_sort |
Jacobs, J. |
title |
A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen |
title_short |
A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen |
title_full |
A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen |
title_fullStr |
A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen |
title_full_unstemmed |
A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen |
title_sort |
himalayan-type indentor-escape tectonics model for the southern part of the late neoproterozoic-early paleozoic east african-antarctic orogen |
publisher |
Geological Society of America |
publishDate |
2004 |
url |
http://nora.nerc.ac.uk/id/eprint/5586/ http://geology.geoscienceworld.org/content/vol31/issue8/ |
long_lat |
ENVELOPE(-27.500,-27.500,-77.000,-77.000) ENVELOPE(-79.000,-79.000,-77.667,-77.667) |
geographic |
Antarctic East Antarctica Dronning Maud Land Coats Land Haag |
geographic_facet |
Antarctic East Antarctica Dronning Maud Land Coats Land Haag |
genre |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica |
op_relation |
Jacobs, J.; Thomas, Robert James. 2004 A Himalayan-type indentor-escape tectonics model for the southern part of the Late Neoproterozoic-Early Paleozoic East African-Antarctic Orogen. Geology, 32 (8). 721-724. https://doi.org/10.1130/G20516.1 <https://doi.org/10.1130/G20516.1> |
op_doi |
https://doi.org/10.1130/G20516.1 |
container_title |
Geology |
container_volume |
32 |
container_issue |
8 |
container_start_page |
721 |
_version_ |
1801383617288470528 |