Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin

The first magnetostratigraphic study of a Pliensbachian-Toarcian succession from the Neuquén Basin is presented. The study was carried out in the Chacay Melehue area (province of Neuquén), in the Rajapalo-Chacay Melehue (RP-CM) section, where a 450m thick marine sedimentary and volcanic sequence is...

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Autor principal: Iglesia Llanos, M.P.
Formato: JOUR
Materias:
Jurassic
magnetostratigraphy
palaeomagnetism
palaeopole position
Pliensbachian
Toarcian
Argentina, Neuquen Province, Neuquen Basin
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00044822_v51_n4_p339_IglesiaLlanos
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00044822_v51_n4_p339_IglesiaLlanos2023-10-03T13:57:17Z Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin Iglesia Llanos, M.P. Jurassic magnetostratigraphy palaeomagnetism palaeopole position Pliensbachian Toarcian Argentina, Neuquen Province, Neuquen Basin The first magnetostratigraphic study of a Pliensbachian-Toarcian succession from the Neuquén Basin is presented. The study was carried out in the Chacay Melehue area (province of Neuquén), in the Rajapalo-Chacay Melehue (RP-CM) section, where a 450m thick marine sedimentary and volcanic sequence is exposed. This section is well exposed and well dated biostratigraphically. For the study, 163 hand samples were collected from 54 sites, corresponding to the late Early Pliensbachian-Middle Toarcian interval. The primary origin of the remanent magnetization isolated in RP-CM was proved by palaeomagnetic field tests. The ages of the polarities represented at each site were assigned on the basis of the ammonite zones of the East Pacific Realm. The correlation between the local magnetostratigraphic scale and the international Magnetic Polarity Time Scale for the Pliensbachian-Toarcian interval shows that almost all the polarity reversals proposed exist in the RP-CM section. In addition, this correlation strengthened that of the ammonite zones of the East Pacific Realm with those of Europe, as well as allowing a better definition of the chronostratigraphical units of the RP-CM section (i.e the Pliensbachian-Toarcian boundary). The palaeomagnetic data yielded a high quality (Q=7) palaeomagnetic pole (PP): Long=82°E, Lat=73,9°S, N=57, A95 =3°, K=36°. This PP also includes the palaeomagnetic directions of the Puesto Araya section (province of Mendoza), which pass the tilt test when considered together with those from the RP-CM section. The position of this PP supports the hypothesis of a south-north movement for South America during the Pliensbachian-Toarcian, as opposed to the static period proposed by many authors for the continent throughout the Jurassic. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00044822_v51_n4_p339_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 Jurassic
magnetostratigraphy
palaeomagnetism
palaeopole position
Pliensbachian
Toarcian
Argentina, Neuquen Province, Neuquen Basin
spellingShingle Jurassic
magnetostratigraphy
palaeomagnetism
palaeopole position
Pliensbachian
Toarcian
Argentina, Neuquen Province, Neuquen Basin
Iglesia Llanos, M.P.
Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin
topic_facet Jurassic
magnetostratigraphy
palaeomagnetism
palaeopole position
Pliensbachian
Toarcian
Argentina, Neuquen Province, Neuquen Basin
description The first magnetostratigraphic study of a Pliensbachian-Toarcian succession from the Neuquén Basin is presented. The study was carried out in the Chacay Melehue area (province of Neuquén), in the Rajapalo-Chacay Melehue (RP-CM) section, where a 450m thick marine sedimentary and volcanic sequence is exposed. This section is well exposed and well dated biostratigraphically. For the study, 163 hand samples were collected from 54 sites, corresponding to the late Early Pliensbachian-Middle Toarcian interval. The primary origin of the remanent magnetization isolated in RP-CM was proved by palaeomagnetic field tests. The ages of the polarities represented at each site were assigned on the basis of the ammonite zones of the East Pacific Realm. The correlation between the local magnetostratigraphic scale and the international Magnetic Polarity Time Scale for the Pliensbachian-Toarcian interval shows that almost all the polarity reversals proposed exist in the RP-CM section. In addition, this correlation strengthened that of the ammonite zones of the East Pacific Realm with those of Europe, as well as allowing a better definition of the chronostratigraphical units of the RP-CM section (i.e the Pliensbachian-Toarcian boundary). The palaeomagnetic data yielded a high quality (Q=7) palaeomagnetic pole (PP): Long=82°E, Lat=73,9°S, N=57, A95 =3°, K=36°. This PP also includes the palaeomagnetic directions of the Puesto Araya section (province of Mendoza), which pass the tilt test when considered together with those from the RP-CM section. The position of this PP supports the hypothesis of a south-north movement for South America during the Pliensbachian-Toarcian, as opposed to the static period proposed by many authors for the continent throughout the Jurassic.
format JOUR
author Iglesia Llanos, M.P.
author_facet Iglesia Llanos, M.P.
author_sort Iglesia Llanos, M.P.
title Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin
title_short Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin
title_full Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin
title_fullStr Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin
title_full_unstemmed Palaeomagnetism and magnetostratigraphy of the Pliensbachian-Toarcian (Jurassic) of the Neuquén Basin
title_sort palaeomagnetism and magnetostratigraphy of the pliensbachian-toarcian (jurassic) of the neuquén basin
url http://hdl.handle.net/20.500.12110/paper_00044822_v51_n4_p339_IglesiaLlanos
work_keys_str_mv AT iglesiallanosmp palaeomagnetismandmagnetostratigraphyofthepliensbachiantoarcianjurassicoftheneuquenbasin
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