Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America

The palaeomagnetic sudy was carried out in five sections cropping out in the Neuquén Basin, which are made up of hundreds metres-thick of ammonite-bearing sedimentary and subordinately, volcanic rocks of Early Jurassic age. These sections are located in the northern part of the basin along the Atuel...

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Detalles Bibliográficos
Autor principal: Iglesia Llanos, Maria Paula
Publicado: 2009
Materias:
Ammonites
Jurassic
Neuquén Basin
Palaeogeography
Palaeomagnetism
ammonite
apparent polar wander path
geomagnetism
magnetic reversal
magnetostratigraphy
paleogeography
paleomagnetism
petrography
Southern Hemisphere
stratigraphy
titanomagnetite
Argentina
Neuquen Basin
Ammonoidea
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v65_n2_p387_IglesiaLlanos
http://hdl.handle.net/20.500.12110/paper_00044822_v65_n2_p387_IglesiaLlanos
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_00044822_v65_n2_p387_IglesiaLlanos2023-06-08T14:26:18Z Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America Iglesia Llanos, Maria Paula Ammonites Jurassic Neuquén Basin Palaeogeography Palaeomagnetism ammonite apparent polar wander path geomagnetism Jurassic magnetic reversal magnetostratigraphy paleogeography paleomagnetism petrography Southern Hemisphere stratigraphy titanomagnetite Argentina Neuquen Basin Ammonoidea The palaeomagnetic sudy was carried out in five sections cropping out in the Neuquén Basin, which are made up of hundreds metres-thick of ammonite-bearing sedimentary and subordinately, volcanic rocks of Early Jurassic age. These sections are located in the northern part of the basin along the Atuel river (Hettangian to Toarcian), and the central part (Pliensbachian to Toarcian) of the basin. From paleomagnetic and petrographical studies two magnetic components carried by titanomagnetites were recognised, one soft bearing a direction that coincides with the local present-day field, and another harder interpreted as the original jurassic according to the palaeomagnetic field tests. Based on the polarities succession isolated in the five sections, a composite magnetostratigraphic scale was elaborated, which is the first of this age in the Southern Hemisphere. Eleven dominantly reversed (JR1 to JR11) and 12 dominantly normal (JN1 to JN12) polarity zones were identified, in relation with 19 ammonite zones from the Andean Region, which were in turn correlated with the international standard geomagnetic time scale. The good fit between the two scales allowed to date some stratigraphic levels with no diagnotic fossils, such as the Sinemurian-Pliensbachian boundary at Puesto Araya, and the Pliensbachian-Toarcian limit at Rapajalo. On the other hand, two palaeomagnetic poles were calculated, one for the Hettangian-Sinemurian (223°E, 51°S, A95= 6°, N = 25) and another for the Pliensbachian-Toarcian (67°E, 74°S, A95= 5°, N = 52). These poles, combined with others selected from the literature, led to the construction of a new apparent polar wander (APW) path of South America for the Late Triassic-Jurassic time interval, which turned out to be dissimilar from previous curves placing the continent in a stationary latitudinal position during most of the Mesozoic. The resultant APW path suggests that South America would have rotated clockwise while it was moving northward. The same shape and chronology is observed in the jurassic path of Eurasia. The latitudinal shifts derived from the palaeomagnetic data are supported by diverse marine faunas from both the southern and northern hemispheres. Fil:Iglesia Llanos, M.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v65_n2_p387_IglesiaLlanos http://hdl.handle.net/20.500.12110/paper_00044822_v65_n2_p387_IglesiaLlanos
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Ammonites
Jurassic
Neuquén Basin
Palaeogeography
Palaeomagnetism
ammonite
apparent polar wander path
geomagnetism
Jurassic
magnetic reversal
magnetostratigraphy
paleogeography
paleomagnetism
petrography
Southern Hemisphere
stratigraphy
titanomagnetite
Argentina
Neuquen Basin
Ammonoidea
spellingShingle Ammonites
Jurassic
Neuquén Basin
Palaeogeography
Palaeomagnetism
ammonite
apparent polar wander path
geomagnetism
Jurassic
magnetic reversal
magnetostratigraphy
paleogeography
paleomagnetism
petrography
Southern Hemisphere
stratigraphy
titanomagnetite
Argentina
Neuquen Basin
Ammonoidea
Iglesia Llanos, Maria Paula
Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America
topic_facet Ammonites
Jurassic
Neuquén Basin
Palaeogeography
Palaeomagnetism
ammonite
apparent polar wander path
geomagnetism
Jurassic
magnetic reversal
magnetostratigraphy
paleogeography
paleomagnetism
petrography
Southern Hemisphere
stratigraphy
titanomagnetite
Argentina
Neuquen Basin
Ammonoidea
description The palaeomagnetic sudy was carried out in five sections cropping out in the Neuquén Basin, which are made up of hundreds metres-thick of ammonite-bearing sedimentary and subordinately, volcanic rocks of Early Jurassic age. These sections are located in the northern part of the basin along the Atuel river (Hettangian to Toarcian), and the central part (Pliensbachian to Toarcian) of the basin. From paleomagnetic and petrographical studies two magnetic components carried by titanomagnetites were recognised, one soft bearing a direction that coincides with the local present-day field, and another harder interpreted as the original jurassic according to the palaeomagnetic field tests. Based on the polarities succession isolated in the five sections, a composite magnetostratigraphic scale was elaborated, which is the first of this age in the Southern Hemisphere. Eleven dominantly reversed (JR1 to JR11) and 12 dominantly normal (JN1 to JN12) polarity zones were identified, in relation with 19 ammonite zones from the Andean Region, which were in turn correlated with the international standard geomagnetic time scale. The good fit between the two scales allowed to date some stratigraphic levels with no diagnotic fossils, such as the Sinemurian-Pliensbachian boundary at Puesto Araya, and the Pliensbachian-Toarcian limit at Rapajalo. On the other hand, two palaeomagnetic poles were calculated, one for the Hettangian-Sinemurian (223°E, 51°S, A95= 6°, N = 25) and another for the Pliensbachian-Toarcian (67°E, 74°S, A95= 5°, N = 52). These poles, combined with others selected from the literature, led to the construction of a new apparent polar wander (APW) path of South America for the Late Triassic-Jurassic time interval, which turned out to be dissimilar from previous curves placing the continent in a stationary latitudinal position during most of the Mesozoic. The resultant APW path suggests that South America would have rotated clockwise while it was moving northward. The same shape and chronology is observed in the jurassic path of Eurasia. The latitudinal shifts derived from the palaeomagnetic data are supported by diverse marine faunas from both the southern and northern hemispheres.
author Iglesia Llanos, Maria Paula
author_facet Iglesia Llanos, Maria Paula
author_sort Iglesia Llanos, Maria Paula
title Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America
title_short Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America
title_full Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America
title_fullStr Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America
title_full_unstemmed Palaeomagnetic study of marine Jurassic strata from the Neuquén Basin: Magnetostratigraphic correlation of the Lower Jurassic and a new apparent polar wander path for South America
title_sort palaeomagnetic study of marine jurassic strata from the neuquén basin: magnetostratigraphic correlation of the lower jurassic and a new apparent polar wander path for south america
publishDate 2009
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v65_n2_p387_IglesiaLlanos
http://hdl.handle.net/20.500.12110/paper_00044822_v65_n2_p387_IglesiaLlanos
work_keys_str_mv AT iglesiallanosmariapaula palaeomagneticstudyofmarinejurassicstratafromtheneuquenbasinmagnetostratigraphiccorrelationofthelowerjurassicandanewapparentpolarwanderpathforsouthamerica
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