The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica
The 1983–1984 season of the joint British Antarctic Survey‐U.S. Antarctic Research Program geology and geophysics project on the Ellsworth‐Whitmore Mountains crustal block (EWM) has yielded new observations and laboratory data relevant to the geological evolution of West Antarctica and its tectonic...
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American Geophysical Union
1987
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ftnerc:oai:nora.nerc.ac.uk:522684 2023-05-15T13:41:43+02:00 The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica Dalziel, I.W.D. Garrett, S.W. Grunow, A.M. Pankhurst, R.J. Storey, B.C. Vennum, W.R. McKenzie, Garry D. 1987 http://nora.nerc.ac.uk/id/eprint/522684/ https://doi.org/10.1029/GM040p0173 unknown American Geophysical Union Dalziel, I.W.D.; Garrett, S.W.; Grunow, A.M.; Pankhurst, R.J.; Storey, B.C.; Vennum, W.R. 1987 The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica. In: McKenzie, Garry D., (ed.) Gondwana Six: Structure, Tectonics, and Geophysics. Washington, D.C., American Geophysical Union, 173-182. (Geophysical Monograph, 40). Publication - Book Section PeerReviewed 1987 ftnerc https://doi.org/10.1029/GM040p0173 2023-02-04T19:48:01Z The 1983–1984 season of the joint British Antarctic Survey‐U.S. Antarctic Research Program geology and geophysics project on the Ellsworth‐Whitmore Mountains crustal block (EWM) has yielded new observations and laboratory data relevant to the geological evolution of West Antarctica and its tectonic relationship to the rest of Gondwanaland. This is a synthesis of results presented in companion papers in this volume. New paleomagnetic data favor a Jurassic reconstruction in which there has been little or no relative displacement between the EWM and the Antarctic Peninsula. They may be restored together, with a 15°–20° counterclockwise rotation and a northward translation of approximately 10° of latitude, to a position on the Pacific side of the Falkland Plateau‐Cape Fold Belt‐Coats Land junction. Orthogneiss exposed at Haag Nunataks represents a Proterozoic cratonization event, and aeromagnetic data demonstrate that related rocks occur beneath the ice from the northeastern edge of the Ellsworth Mountains as far as the base of the Antarctic Peninsula. Although this basement does not demonstrably extend beneath the EWM, retention of the present‐day relative positions of the Antarctic Peninsula, Haag Nunataks, and the EWM is geologically compatible with the above reconstruction. To the south of the block, the igneous and sedimentary rocks of the Thiel Mountains are recognized as part of the Precambrian basement and Phanerozoic successions of the Transantarctic Mountains, geologically and geophysically distinct from the folded sedimentary succession of the EWM. The latter are mostly lithologically correlative with the lower part of the thick Cambrian‐Permian Ellsworth Mountains succession, and throughout much of the area, share the same simple structural style and trend related to post‐Permian folding. Discordant and more complex structures are observed at separate localities on the margins of the EWM. The youngest exposed rocks in the EWM are a suite of Middle Jurassic peraluminous “S‐type” granites. These are ... Book Part Antarc* Antarctic Antarctic Peninsula Antarctica British Antarctic Survey West Antarctica Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Antarctic Peninsula West Antarctica Transantarctic Mountains Pacific Ellsworth Mountains ENVELOPE(-85.000,-85.000,-78.750,-78.750) Falkland Plateau ENVELOPE(-50.000,-50.000,-51.000,-51.000) Coats Land ENVELOPE(-27.500,-27.500,-77.000,-77.000) Haag ENVELOPE(-79.000,-79.000,-77.667,-77.667) Whitmore Mountains ENVELOPE(-104.000,-104.000,-82.500,-82.500) Thiel Mountains ENVELOPE(-91.000,-91.000,-85.250,-85.250) Haag Nunataks ENVELOPE(-78.400,-78.400,-77.000,-77.000) 173 182 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
The 1983–1984 season of the joint British Antarctic Survey‐U.S. Antarctic Research Program geology and geophysics project on the Ellsworth‐Whitmore Mountains crustal block (EWM) has yielded new observations and laboratory data relevant to the geological evolution of West Antarctica and its tectonic relationship to the rest of Gondwanaland. This is a synthesis of results presented in companion papers in this volume. New paleomagnetic data favor a Jurassic reconstruction in which there has been little or no relative displacement between the EWM and the Antarctic Peninsula. They may be restored together, with a 15°–20° counterclockwise rotation and a northward translation of approximately 10° of latitude, to a position on the Pacific side of the Falkland Plateau‐Cape Fold Belt‐Coats Land junction. Orthogneiss exposed at Haag Nunataks represents a Proterozoic cratonization event, and aeromagnetic data demonstrate that related rocks occur beneath the ice from the northeastern edge of the Ellsworth Mountains as far as the base of the Antarctic Peninsula. Although this basement does not demonstrably extend beneath the EWM, retention of the present‐day relative positions of the Antarctic Peninsula, Haag Nunataks, and the EWM is geologically compatible with the above reconstruction. To the south of the block, the igneous and sedimentary rocks of the Thiel Mountains are recognized as part of the Precambrian basement and Phanerozoic successions of the Transantarctic Mountains, geologically and geophysically distinct from the folded sedimentary succession of the EWM. The latter are mostly lithologically correlative with the lower part of the thick Cambrian‐Permian Ellsworth Mountains succession, and throughout much of the area, share the same simple structural style and trend related to post‐Permian folding. Discordant and more complex structures are observed at separate localities on the margins of the EWM. The youngest exposed rocks in the EWM are a suite of Middle Jurassic peraluminous “S‐type” granites. These are ... |
author2 |
McKenzie, Garry D. |
format |
Book Part |
author |
Dalziel, I.W.D. Garrett, S.W. Grunow, A.M. Pankhurst, R.J. Storey, B.C. Vennum, W.R. |
spellingShingle |
Dalziel, I.W.D. Garrett, S.W. Grunow, A.M. Pankhurst, R.J. Storey, B.C. Vennum, W.R. The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica |
author_facet |
Dalziel, I.W.D. Garrett, S.W. Grunow, A.M. Pankhurst, R.J. Storey, B.C. Vennum, W.R. |
author_sort |
Dalziel, I.W.D. |
title |
The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica |
title_short |
The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica |
title_full |
The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica |
title_fullStr |
The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica |
title_full_unstemmed |
The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica |
title_sort |
ellsworth-whitmore mountains crustal block: its role in the tectonic evolution of west antarctica |
publisher |
American Geophysical Union |
publishDate |
1987 |
url |
http://nora.nerc.ac.uk/id/eprint/522684/ https://doi.org/10.1029/GM040p0173 |
long_lat |
ENVELOPE(-85.000,-85.000,-78.750,-78.750) ENVELOPE(-50.000,-50.000,-51.000,-51.000) ENVELOPE(-27.500,-27.500,-77.000,-77.000) ENVELOPE(-79.000,-79.000,-77.667,-77.667) ENVELOPE(-104.000,-104.000,-82.500,-82.500) ENVELOPE(-91.000,-91.000,-85.250,-85.250) ENVELOPE(-78.400,-78.400,-77.000,-77.000) |
geographic |
Antarctic The Antarctic Antarctic Peninsula West Antarctica Transantarctic Mountains Pacific Ellsworth Mountains Falkland Plateau Coats Land Haag Whitmore Mountains Thiel Mountains Haag Nunataks |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula West Antarctica Transantarctic Mountains Pacific Ellsworth Mountains Falkland Plateau Coats Land Haag Whitmore Mountains Thiel Mountains Haag Nunataks |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica British Antarctic Survey West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica British Antarctic Survey West Antarctica |
op_relation |
Dalziel, I.W.D.; Garrett, S.W.; Grunow, A.M.; Pankhurst, R.J.; Storey, B.C.; Vennum, W.R. 1987 The Ellsworth-Whitmore Mountains crustal block: Its role in the tectonic evolution of West Antarctica. In: McKenzie, Garry D., (ed.) Gondwana Six: Structure, Tectonics, and Geophysics. Washington, D.C., American Geophysical Union, 173-182. (Geophysical Monograph, 40). |
op_doi |
https://doi.org/10.1029/GM040p0173 |
container_start_page |
173 |
op_container_end_page |
182 |
_version_ |
1766154442518822912 |