Models of geomagnetic secular variations on recent times for South America

Palaeosecular variations of the geomagnetic field obtained from palaeomagnetic and radiometric studies carried out on the bottom sediments from three lakes in southwestern Argentina (records extend back to about 6000 years by 14C dating) were compared with results from different theoretical models,...

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Autor principal: Sinito, A.M.
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00319201_v64_n2-4_p133_Sinito
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spelling todo:paper_00319201_v64_n2-4_p133_Sinito2023-10-03T14:43:32Z Models of geomagnetic secular variations on recent times for South America Sinito, A.M. Alldredge- Hurwitz model geomagnetic field palaeomagnetism secular variation Argentina Palaeosecular variations of the geomagnetic field obtained from palaeomagnetic and radiometric studies carried out on the bottom sediments from three lakes in southwestern Argentina (records extend back to about 6000 years by 14C dating) were compared with results from different theoretical models, which suggested the possible sources of the field. Attempts were then made to simulate long period secular variations using modified Alldredge and Hurwitz's models. The Alldredge and Hurwitz model uses a central dipole and eight radial dipoles, all at the same distance from the centre of the Earth, as a first approximation to the sources of the geomagnetic field. The modified models, which have been used to describe the northern hemisphere data, comprise eight radial dipoles, which oscillate sinusoidally and/or drift. The different parameters of the models were fitted to the palaeomagnetic data from southwestern Argentina. The best fit was obtained with a mixed model; between 6000 and 3000 years BP all radial dipoles oscillate and some of them drift as well. Later the drift rates become lower and, finally, between 1700 years BP and present times, all radial dipoles only oscillate. © 1990. Fil:Sinito, A.M. 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_00319201_v64_n2-4_p133_Sinito
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Alldredge- Hurwitz model
geomagnetic field
palaeomagnetism
secular variation
Argentina
spellingShingle Alldredge- Hurwitz model
geomagnetic field
palaeomagnetism
secular variation
Argentina
Sinito, A.M.
Models of geomagnetic secular variations on recent times for South America
topic_facet Alldredge- Hurwitz model
geomagnetic field
palaeomagnetism
secular variation
Argentina
description Palaeosecular variations of the geomagnetic field obtained from palaeomagnetic and radiometric studies carried out on the bottom sediments from three lakes in southwestern Argentina (records extend back to about 6000 years by 14C dating) were compared with results from different theoretical models, which suggested the possible sources of the field. Attempts were then made to simulate long period secular variations using modified Alldredge and Hurwitz's models. The Alldredge and Hurwitz model uses a central dipole and eight radial dipoles, all at the same distance from the centre of the Earth, as a first approximation to the sources of the geomagnetic field. The modified models, which have been used to describe the northern hemisphere data, comprise eight radial dipoles, which oscillate sinusoidally and/or drift. The different parameters of the models were fitted to the palaeomagnetic data from southwestern Argentina. The best fit was obtained with a mixed model; between 6000 and 3000 years BP all radial dipoles oscillate and some of them drift as well. Later the drift rates become lower and, finally, between 1700 years BP and present times, all radial dipoles only oscillate. © 1990.
format JOUR
author Sinito, A.M.
author_facet Sinito, A.M.
author_sort Sinito, A.M.
title Models of geomagnetic secular variations on recent times for South America
title_short Models of geomagnetic secular variations on recent times for South America
title_full Models of geomagnetic secular variations on recent times for South America
title_fullStr Models of geomagnetic secular variations on recent times for South America
title_full_unstemmed Models of geomagnetic secular variations on recent times for South America
title_sort models of geomagnetic secular variations on recent times for south america
url http://hdl.handle.net/20.500.12110/paper_00319201_v64_n2-4_p133_Sinito
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