Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina
Summary. Palaeomagnetic data from 71 hand samples of igneous rocks of Late Ordovician age exposed in western Argentina (31.3°S, 69.4°W, Alcaparrosa Formation) are given. Stable remanent magnetization was isolated in the majority of samples; they yield a palaeomagnetic pole at 56°S 33°E (N= 8, α95= 1...
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todo:paper_00168009_v55_n1_p143_Vilas2023-10-03T14:14:50Z Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina Vilas, J.F. Valencio, D.A. Summary. Palaeomagnetic data from 71 hand samples of igneous rocks of Late Ordovician age exposed in western Argentina (31.3°S, 69.4°W, Alcaparrosa Formation) are given. Stable remanent magnetization was isolated in the majority of samples; they yield a palaeomagnetic pole at 56°S 33°E (N= 8, α95= 16°). Whole rock K‐Ar age determinations yield an age of 416 ± 10 Myr for a pillow lava of the Alcaparrosa Formation. Palaeomagnetic data for South America, Africa, Australia, Antarctica and India suggest that Gondwana was a unit at least as far back as 1000 Myr. The palaeomagnetic data define a rapid polar migration for Gondwana in Ordovician time which is consistent with the widespread occurrences of Late Ordovician glacial deposits across this supercontinent. Copyright © 1978, Wiley Blackwell. All rights reserved Fil:Vilas, J.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Valencio, D.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00168009_v55_n1_p143_Vilas |
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Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-134 |
collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
description |
Summary. Palaeomagnetic data from 71 hand samples of igneous rocks of Late Ordovician age exposed in western Argentina (31.3°S, 69.4°W, Alcaparrosa Formation) are given. Stable remanent magnetization was isolated in the majority of samples; they yield a palaeomagnetic pole at 56°S 33°E (N= 8, α95= 16°). Whole rock K‐Ar age determinations yield an age of 416 ± 10 Myr for a pillow lava of the Alcaparrosa Formation. Palaeomagnetic data for South America, Africa, Australia, Antarctica and India suggest that Gondwana was a unit at least as far back as 1000 Myr. The palaeomagnetic data define a rapid polar migration for Gondwana in Ordovician time which is consistent with the widespread occurrences of Late Ordovician glacial deposits across this supercontinent. Copyright © 1978, Wiley Blackwell. All rights reserved |
format |
JOUR |
author |
Vilas, J.F. Valencio, D.A. |
spellingShingle |
Vilas, J.F. Valencio, D.A. Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina |
author_facet |
Vilas, J.F. Valencio, D.A. |
author_sort |
Vilas, J.F. |
title |
Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina |
title_short |
Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina |
title_full |
Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina |
title_fullStr |
Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina |
title_full_unstemmed |
Palaeomagnetism and K—Ar age of the Upper Ordovician Alcaparrosa Formation, Argentina |
title_sort |
palaeomagnetism and k—ar age of the upper ordovician alcaparrosa formation, argentina |
url |
http://hdl.handle.net/20.500.12110/paper_00168009_v55_n1_p143_Vilas |
work_keys_str_mv |
AT vilasjf palaeomagnetismandkarageoftheupperordovicianalcaparrosaformationargentina AT valencioda palaeomagnetismandkarageoftheupperordovicianalcaparrosaformationargentina |
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1807318034109431808 |