The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy

Summary. In this paper we show that: (1) The positions of the Cretaceous palaeomagnetic poles (PP) for South America and Africa exhibit elongated distributions that are due to rapid movement of these continents from the south pole. (2) The positions of the Middle—late Jurassic virtual geomagnetic po...

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Publicado: 1983
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00168009_v73_n1_p135_Valencio
http://hdl.handle.net/20.500.12110/paper_00168009_v73_n1_p135_Valencio
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00168009_v73_n1_p135_Valencio
record_format dspace
spelling paper:paper_00168009_v73_n1_p135_Valencio2023-06-08T14:38:58Z The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy Summary. In this paper we show that: (1) The positions of the Cretaceous palaeomagnetic poles (PP) for South America and Africa exhibit elongated distributions that are due to rapid movement of these continents from the south pole. (2) The positions of the Middle—late Jurassic virtual geomagnetic poles for South America exhibit an elongated distribution along the meridians 20–200° E; it is suggested that this is due to a rapid shift of South America in Middle—late Jurassic time. (3) The late early—early late Cretaceous sections of the apparent polar wandering paths for South America and Africa are consistent with South Atlantic seafloor spreading data. On the basis of the comparison of the reliable late Palaeozoic—late Cretaceous PPs for South America and Africa, taking into account the restrictions established by geological, palaeontological and seafloor spreading data, it is suggested that minor movements could have occurred within Western Gondwana in middle—late Jurassic time along a narrow zone which later became the South Atlantic divergent boundary. Four ‘hairpins’ are defined in the late Palaeozoic—late Cretaceous section of the apparent polar wandering path for South America; the two youngest of these can be correlated with the origin of the South Atlantic Ocean basin and the onset of the Andean Orogeny, respectively. The magnetostratigraphy for the Serra Geral lava flow sequence suggests that some of these flows were poured out rapidly without significant interruption. Copyright © 1983, Wiley Blackwell. All rights reserved 1983 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00168009_v73_n1_p135_Valencio http://hdl.handle.net/20.500.12110/paper_00168009_v73_n1_p135_Valencio
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. In this paper we show that: (1) The positions of the Cretaceous palaeomagnetic poles (PP) for South America and Africa exhibit elongated distributions that are due to rapid movement of these continents from the south pole. (2) The positions of the Middle—late Jurassic virtual geomagnetic poles for South America exhibit an elongated distribution along the meridians 20–200° E; it is suggested that this is due to a rapid shift of South America in Middle—late Jurassic time. (3) The late early—early late Cretaceous sections of the apparent polar wandering paths for South America and Africa are consistent with South Atlantic seafloor spreading data. On the basis of the comparison of the reliable late Palaeozoic—late Cretaceous PPs for South America and Africa, taking into account the restrictions established by geological, palaeontological and seafloor spreading data, it is suggested that minor movements could have occurred within Western Gondwana in middle—late Jurassic time along a narrow zone which later became the South Atlantic divergent boundary. Four ‘hairpins’ are defined in the late Palaeozoic—late Cretaceous section of the apparent polar wandering path for South America; the two youngest of these can be correlated with the origin of the South Atlantic Ocean basin and the onset of the Andean Orogeny, respectively. The magnetostratigraphy for the Serra Geral lava flow sequence suggests that some of these flows were poured out rapidly without significant interruption. Copyright © 1983, Wiley Blackwell. All rights reserved
title The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy
spellingShingle The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy
title_short The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy
title_full The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy
title_fullStr The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy
title_full_unstemmed The significance of the pdaeomagnetism of Jurassic—Cretaceous rocks from South America: predrift movements, hairpins and magnetostratigraphy
title_sort significance of the pdaeomagnetism of jurassic—cretaceous rocks from south america: predrift movements, hairpins and magnetostratigraphy
publishDate 1983
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00168009_v73_n1_p135_Valencio
http://hdl.handle.net/20.500.12110/paper_00168009_v73_n1_p135_Valencio
_version_ 1768541828854841344

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