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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Autores principales: Vilas, J.F., Valencio, D.A.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00168009_v55_n1_p143_Vilas
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spelling 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
institution 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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