Paleomagnetic constrain for the age of the Matasiete Formation

The results of a paleomagnetic study performed over the Matasiete Formation, belonging to the Chubut Group, are presented. Alternating field and thermal demagnetization techniques were employed to analyze the stability of the magnetic remanence. The studied specimens have relatively high magnetic su...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autor principal: Mena, M.
Formato: JOUR
Materias:
Aptian
Cretaceous normal superchron
Matasiete Formation
Paleomagnetism
age determination
demagnetization
geomagnetic field
magnetic reversal
magnetite
magnetostratigraphy
paleomagnetism
principal component analysis
thermoremanent magnetization
virtual geomagnetic pole
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00044822_v66_n3_p380_Mena
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00044822_v66_n3_p380_Mena
record_format dspace
spelling todo:paper_00044822_v66_n3_p380_Mena2023-10-03T13:58:43Z Paleomagnetic constrain for the age of the Matasiete Formation Mena, M. Aptian Cretaceous normal superchron Matasiete Formation Paleomagnetism age determination Aptian demagnetization geomagnetic field magnetic reversal magnetite magnetostratigraphy paleomagnetism principal component analysis thermoremanent magnetization virtual geomagnetic pole The results of a paleomagnetic study performed over the Matasiete Formation, belonging to the Chubut Group, are presented. Alternating field and thermal demagnetization techniques were employed to analyze the stability of the magnetic remanence. The studied specimens have relatively high magnetic susceptibilities. They have soft viscous and low unblocking temperature components. These components are statistically coincident with each other and with the geocentric axial dipole field direction for the locality. The magnetic remanences were removed below 580°C, indicating that magnetite is the main remanence carrier. Characteristic remanent magnetization directions were determined by principal component analysis with a maximum angular deviation smaller than 5°. Given the similar attitudes of the strata, the fold-tests are indeterminate. When the structural correction is applied, the concentration of characteristic remanent magnetization directions increases. That increase suggests that these remanences are pretectonic. All virtual geomagnetic poles corresponding to the remanent magnetizations have a normal polarity. The paleomagnetic pole calculated in this study for the Matasiete Formation is located at 84.7°S, 161.2°E (n=34, k=17.51, A95=6.1). That position is statistically equivalent to those of the PPs from Cerro Barcino Formation (112-125 Ma) and Los Adobes Formation (112-130 Ma), outcropping at Central Patagonia. The coincidence of these paleomagnetic poles supports the Hauterivian?-Barremian-Aptian age assigned to the Matasiete Formation on the base of different fosiliferous associations. As the normal polarity of all virtual geomagnetic poles suggests that these rocks were deposited during the Cretaceous normal superchron, an Aptian age is proposed for the Matasiete Formation. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00044822_v66_n3_p380_Mena
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Aptian
Cretaceous normal superchron
Matasiete Formation
Paleomagnetism
age determination
Aptian
demagnetization
geomagnetic field
magnetic reversal
magnetite
magnetostratigraphy
paleomagnetism
principal component analysis
thermoremanent magnetization
virtual geomagnetic pole
spellingShingle Aptian
Cretaceous normal superchron
Matasiete Formation
Paleomagnetism
age determination
Aptian
demagnetization
geomagnetic field
magnetic reversal
magnetite
magnetostratigraphy
paleomagnetism
principal component analysis
thermoremanent magnetization
virtual geomagnetic pole
Mena, M.
Paleomagnetic constrain for the age of the Matasiete Formation
topic_facet Aptian
Cretaceous normal superchron
Matasiete Formation
Paleomagnetism
age determination
Aptian
demagnetization
geomagnetic field
magnetic reversal
magnetite
magnetostratigraphy
paleomagnetism
principal component analysis
thermoremanent magnetization
virtual geomagnetic pole
description The results of a paleomagnetic study performed over the Matasiete Formation, belonging to the Chubut Group, are presented. Alternating field and thermal demagnetization techniques were employed to analyze the stability of the magnetic remanence. The studied specimens have relatively high magnetic susceptibilities. They have soft viscous and low unblocking temperature components. These components are statistically coincident with each other and with the geocentric axial dipole field direction for the locality. The magnetic remanences were removed below 580°C, indicating that magnetite is the main remanence carrier. Characteristic remanent magnetization directions were determined by principal component analysis with a maximum angular deviation smaller than 5°. Given the similar attitudes of the strata, the fold-tests are indeterminate. When the structural correction is applied, the concentration of characteristic remanent magnetization directions increases. That increase suggests that these remanences are pretectonic. All virtual geomagnetic poles corresponding to the remanent magnetizations have a normal polarity. The paleomagnetic pole calculated in this study for the Matasiete Formation is located at 84.7°S, 161.2°E (n=34, k=17.51, A95=6.1). That position is statistically equivalent to those of the PPs from Cerro Barcino Formation (112-125 Ma) and Los Adobes Formation (112-130 Ma), outcropping at Central Patagonia. The coincidence of these paleomagnetic poles supports the Hauterivian?-Barremian-Aptian age assigned to the Matasiete Formation on the base of different fosiliferous associations. As the normal polarity of all virtual geomagnetic poles suggests that these rocks were deposited during the Cretaceous normal superchron, an Aptian age is proposed for the Matasiete Formation.
format JOUR
author Mena, M.
author_facet Mena, M.
author_sort Mena, M.
title Paleomagnetic constrain for the age of the Matasiete Formation
title_short Paleomagnetic constrain for the age of the Matasiete Formation
title_full Paleomagnetic constrain for the age of the Matasiete Formation
title_fullStr Paleomagnetic constrain for the age of the Matasiete Formation
title_full_unstemmed Paleomagnetic constrain for the age of the Matasiete Formation
title_sort paleomagnetic constrain for the age of the matasiete formation
url http://hdl.handle.net/20.500.12110/paper_00044822_v66_n3_p380_Mena
work_keys_str_mv AT menam paleomagneticconstrainfortheageofthematasieteformation
_version_ 1807316187123548160

Ejemplares similares