Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes

Widespread clockwise rotations in Mesozoic and Lower Tertiary rocks of northern Chile have been interpreted as the sum of two rotational events separated in time: an early rotation related to local deformation plus a late rotation related to wholesale rotation of northern Chile linked to Late Cenozo...

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Detalles Bibliográficos
Autor principal: Somoza, Ruben
Publicado: 2002
Materias:
Central Andes
Chile
Paleomagnetism
Precordillera
Rotation
Cretaceous
forearc basin
paleomagnetism
tectonic rotation
Tertiary
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v194_n3-4_p369_Somoza
http://hdl.handle.net/20.500.12110/paper_0012821X_v194_n3-4_p369_Somoza
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_0012821X_v194_n3-4_p369_Somoza
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spelling paper:paper_0012821X_v194_n3-4_p369_Somoza2023-06-08T14:35:29Z Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes Somoza, Ruben Central Andes Chile Paleomagnetism Precordillera Rotation Cretaceous forearc basin paleomagnetism tectonic rotation Tertiary Chile Widespread clockwise rotations in Mesozoic and Lower Tertiary rocks of northern Chile have been interpreted as the sum of two rotational events separated in time: an early rotation related to local deformation plus a late rotation related to wholesale rotation of northern Chile linked to Late Cenozoic oroclinal bending in the Central Andes. In this paper we report new paleomagnetic data from Cretaceous, upper Oligocene and Miocene sedimentary rocks in the Precordillera of northern Chile. The results suggest that all these rocks acquired their remanence at or close to the time of deposition. The lack of rotation in undeformed lower Miocene strata clearly indicates that clockwise rotations found in underlying, faulted and folded Cretaceous rocks were completed before the Late Cenozoic. Results from nearby localities in deformed upper Oligocene strata would argue for little (∼ 5°) rotation since the late Oligocene. Data from widely separated Miocene localities covering an area of about 5000 km2 in the Calama basin strongly suggest that northern Chile did not undergo significant wholesale rotation during the Late Cenozoic. This, together with previous paleomagnetic evidence against Neogene rigid-body-like rotation of the southern Peruvian forearc, suggests that the curved shape of the Central Andean forearc was not significantly enhanced during the Late Cenozoic. By inference, all of the rotation in most Mesozoic and Lower Tertiary rocks of northern Chile was accomplished in the Cretaceous and/ or Early Cenozoic, when the locus of deformation in the Central Andes was localized in the present forearc region. © 2002 Elsevier Science B.V. All rights reserved. Fil:Somoza, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v194_n3-4_p369_Somoza http://hdl.handle.net/20.500.12110/paper_0012821X_v194_n3-4_p369_Somoza
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Central Andes
Chile
Paleomagnetism
Precordillera
Rotation
Cretaceous
forearc basin
paleomagnetism
tectonic rotation
Tertiary
Chile
spellingShingle Central Andes
Chile
Paleomagnetism
Precordillera
Rotation
Cretaceous
forearc basin
paleomagnetism
tectonic rotation
Tertiary
Chile
Somoza, Ruben
Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes
topic_facet Central Andes
Chile
Paleomagnetism
Precordillera
Rotation
Cretaceous
forearc basin
paleomagnetism
tectonic rotation
Tertiary
Chile
description Widespread clockwise rotations in Mesozoic and Lower Tertiary rocks of northern Chile have been interpreted as the sum of two rotational events separated in time: an early rotation related to local deformation plus a late rotation related to wholesale rotation of northern Chile linked to Late Cenozoic oroclinal bending in the Central Andes. In this paper we report new paleomagnetic data from Cretaceous, upper Oligocene and Miocene sedimentary rocks in the Precordillera of northern Chile. The results suggest that all these rocks acquired their remanence at or close to the time of deposition. The lack of rotation in undeformed lower Miocene strata clearly indicates that clockwise rotations found in underlying, faulted and folded Cretaceous rocks were completed before the Late Cenozoic. Results from nearby localities in deformed upper Oligocene strata would argue for little (∼ 5°) rotation since the late Oligocene. Data from widely separated Miocene localities covering an area of about 5000 km2 in the Calama basin strongly suggest that northern Chile did not undergo significant wholesale rotation during the Late Cenozoic. This, together with previous paleomagnetic evidence against Neogene rigid-body-like rotation of the southern Peruvian forearc, suggests that the curved shape of the Central Andean forearc was not significantly enhanced during the Late Cenozoic. By inference, all of the rotation in most Mesozoic and Lower Tertiary rocks of northern Chile was accomplished in the Cretaceous and/ or Early Cenozoic, when the locus of deformation in the Central Andes was localized in the present forearc region. © 2002 Elsevier Science B.V. All rights reserved.
author Somoza, Ruben
author_facet Somoza, Ruben
author_sort Somoza, Ruben
title Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes
title_short Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes
title_full Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes
title_fullStr Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes
title_full_unstemmed Paleomagnetism in the Precordillera of northern Chile (22°30'S): Implications for the history of tectonic rotations in the Central Andes
title_sort paleomagnetism in the precordillera of northern chile (22°30's): implications for the history of tectonic rotations in the central andes
publishDate 2002
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v194_n3-4_p369_Somoza
http://hdl.handle.net/20.500.12110/paper_0012821X_v194_n3-4_p369_Somoza
work_keys_str_mv AT somozaruben paleomagnetismintheprecordilleraofnorthernchile2230simplicationsforthehistoryoftectonicrotationsinthecentralandes
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