Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)

Geomagnetic directions recorded in a lower Jurassic stratigraphic sequence that outcrops at the Breggia Gorge are analyzed. A new method to identify directions suitable for calculating a time-averaged dipolar geomagnetic direction has been applied to calculate a hypothetical early Jurassic geocentri...

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Detalles Bibliográficos
Autores principales: Vizán, H., Van Zele, M.A.
Formato: JOUR
Materias:
Alps
Early jurassic
Geomagnetism
Polarity reversals
Switzerland
Jurassic
magnetic reversal
paleomagnetism
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00319201_v125_n1-4_p19_Vizan
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00319201_v125_n1-4_p19_Vizan
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spelling todo:paper_00319201_v125_n1-4_p19_Vizan2023-10-03T14:43:27Z Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland) Vizán, H. Van Zele, M.A. Alps Early jurassic Geomagnetism Polarity reversals Switzerland Jurassic magnetic reversal paleomagnetism Switzerland Geomagnetic directions recorded in a lower Jurassic stratigraphic sequence that outcrops at the Breggia Gorge are analyzed. A new method to identify directions suitable for calculating a time-averaged dipolar geomagnetic direction has been applied to calculate a hypothetical early Jurassic geocentric axial dipole. The data were separated to identify normal/reverse directions, corresponding to periods of stable field, and intermediate directions. From an analysis of the data in the palaeogeographic coordinates of the Breggia Gorge at the time of the acquisition of the remanence, it is suggested that polarity transitions in the early Jurassic behaved in a similar manner to that described for late Cenozoic reversals, with the VGPs preferentially following longitudinal paths. The preferred paths coincide with a time-averaged location of the Jurassic subduction area of Pangea. This agreement could indicate a connection between the geometry of the reversals and the subduction zones. An analysis to test whether both N/R and intermediate directions have similar preferred distributions suggests that the underlying structure of the early Jurassic geomagnetic field was similar to that observed for the late Cenozoic. The dispersion of directions with inclinations around O° is higher than those belonging to N/R polarity directions, suggesting that there was an enhancement of fluctuations of the geomagnetic field during intermediate states in the early Jurassic. © 2001 Elsevier Science B.V. Fil:Vizán, H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Van Zele, M.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_00319201_v125_n1-4_p19_Vizan
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Alps
Early jurassic
Geomagnetism
Polarity reversals
Switzerland
Jurassic
magnetic reversal
paleomagnetism
Switzerland
spellingShingle Alps
Early jurassic
Geomagnetism
Polarity reversals
Switzerland
Jurassic
magnetic reversal
paleomagnetism
Switzerland
Vizán, H.
Van Zele, M.A.
Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)
topic_facet Alps
Early jurassic
Geomagnetism
Polarity reversals
Switzerland
Jurassic
magnetic reversal
paleomagnetism
Switzerland
description Geomagnetic directions recorded in a lower Jurassic stratigraphic sequence that outcrops at the Breggia Gorge are analyzed. A new method to identify directions suitable for calculating a time-averaged dipolar geomagnetic direction has been applied to calculate a hypothetical early Jurassic geocentric axial dipole. The data were separated to identify normal/reverse directions, corresponding to periods of stable field, and intermediate directions. From an analysis of the data in the palaeogeographic coordinates of the Breggia Gorge at the time of the acquisition of the remanence, it is suggested that polarity transitions in the early Jurassic behaved in a similar manner to that described for late Cenozoic reversals, with the VGPs preferentially following longitudinal paths. The preferred paths coincide with a time-averaged location of the Jurassic subduction area of Pangea. This agreement could indicate a connection between the geometry of the reversals and the subduction zones. An analysis to test whether both N/R and intermediate directions have similar preferred distributions suggests that the underlying structure of the early Jurassic geomagnetic field was similar to that observed for the late Cenozoic. The dispersion of directions with inclinations around O° is higher than those belonging to N/R polarity directions, suggesting that there was an enhancement of fluctuations of the geomagnetic field during intermediate states in the early Jurassic. © 2001 Elsevier Science B.V.
format JOUR
author Vizán, H.
Van Zele, M.A.
author_facet Vizán, H.
Van Zele, M.A.
author_sort Vizán, H.
title Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)
title_short Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)
title_full Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)
title_fullStr Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)
title_full_unstemmed Analysis of the early Jurassic geomagnetic data recorded at the Breggia Gorge (Ticino, Switzerland)
title_sort analysis of the early jurassic geomagnetic data recorded at the breggia gorge (ticino, switzerland)
url http://hdl.handle.net/20.500.12110/paper_00319201_v125_n1-4_p19_Vizan
work_keys_str_mv AT vizanh analysisoftheearlyjurassicgeomagneticdatarecordedatthebreggiagorgeticinoswitzerland
AT vanzelema analysisoftheearlyjurassicgeomagneticdatarecordedatthebreggiagorgeticinoswitzerland
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