Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence

A paleomagnetic study of Eocene volcanic rocks in Patagonia yields high unblocking temperature and high-coercivity magnetizations. Combining these results with those of a previous study on Patagonian Eocene basalts yields a high-precision, high-quality pole located at latitude 81°S, longitude 337.4°...

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Autor principal: Somoza, R.
Formato: JOUR
Materias:
Cenozoic
Cretaceous
Eocene
fold and thrust belt
forearc basin
magnetic fabric
magnetization
paleogeography
paleomagnetism
seafloor
tectonic reconstruction
volcanic rock
Drake Passage
South America
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_21699313_v112_n3_p_Somoza
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_21699313_v112_n3_p_Somoza2023-10-03T16:39:56Z Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence Somoza, R. Cenozoic Cretaceous Eocene fold and thrust belt forearc basin magnetic fabric magnetization paleogeography paleomagnetism seafloor tectonic reconstruction volcanic rock Drake Passage South America A paleomagnetic study of Eocene volcanic rocks in Patagonia yields high unblocking temperature and high-coercivity magnetizations. Combining these results with those of a previous study on Patagonian Eocene basalts yields a high-precision, high-quality pole located at latitude 81°S, longitude 337.4°E, A95 = 5.7°. Critically, this paleopole is indistinguishable from that of the Late Cretaceous (circa 85-65 Ma) pole position of South America, indicating that the plate was essentially motionless with respect to the spin axis for a period of ∼45 m.y. The pole position places South America at higher (∼5°) than present-day latitudes during the Eocene, indicating that northward continental motion toward present-day latitudes must have been accomplished sometime since the late Eocene. Paleomagnetic and tectonic correlation admits the hypothesis that Cenozoic northward drift was associated with Oligocene-Miocene extension in the southern continental edge, leading to the opening of the Drake Passage, and it agrees with the timing of foredeep formation and development of fold-thrust belts in the northern continental edge. This positive correlation between the paleomagnetically predicted drift of a major continent with extension at its trailing edge and convergence at its leading edge during times for which seafloor tectonic fabric and the geological record are particularly well preserved illustrates the utility of paleomagnetism in constraining paleogeographic and tectonic reconstructions for pre-Cretaceous times. Copyright 2007 by the American Geophysical Union. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_21699313_v112_n3_p_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 Cenozoic
Cretaceous
Eocene
fold and thrust belt
forearc basin
magnetic fabric
magnetization
paleogeography
paleomagnetism
seafloor
tectonic reconstruction
volcanic rock
Drake Passage
South America
spellingShingle Cenozoic
Cretaceous
Eocene
fold and thrust belt
forearc basin
magnetic fabric
magnetization
paleogeography
paleomagnetism
seafloor
tectonic reconstruction
volcanic rock
Drake Passage
South America
Somoza, R.
Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence
topic_facet Cenozoic
Cretaceous
Eocene
fold and thrust belt
forearc basin
magnetic fabric
magnetization
paleogeography
paleomagnetism
seafloor
tectonic reconstruction
volcanic rock
Drake Passage
South America
description A paleomagnetic study of Eocene volcanic rocks in Patagonia yields high unblocking temperature and high-coercivity magnetizations. Combining these results with those of a previous study on Patagonian Eocene basalts yields a high-precision, high-quality pole located at latitude 81°S, longitude 337.4°E, A95 = 5.7°. Critically, this paleopole is indistinguishable from that of the Late Cretaceous (circa 85-65 Ma) pole position of South America, indicating that the plate was essentially motionless with respect to the spin axis for a period of ∼45 m.y. The pole position places South America at higher (∼5°) than present-day latitudes during the Eocene, indicating that northward continental motion toward present-day latitudes must have been accomplished sometime since the late Eocene. Paleomagnetic and tectonic correlation admits the hypothesis that Cenozoic northward drift was associated with Oligocene-Miocene extension in the southern continental edge, leading to the opening of the Drake Passage, and it agrees with the timing of foredeep formation and development of fold-thrust belts in the northern continental edge. This positive correlation between the paleomagnetically predicted drift of a major continent with extension at its trailing edge and convergence at its leading edge during times for which seafloor tectonic fabric and the geological record are particularly well preserved illustrates the utility of paleomagnetism in constraining paleogeographic and tectonic reconstructions for pre-Cretaceous times. Copyright 2007 by the American Geophysical Union.
format JOUR
author Somoza, R.
author_facet Somoza, R.
author_sort Somoza, R.
title Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence
title_short Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence
title_full Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence
title_fullStr Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence
title_full_unstemmed Eocene paleomagnetic pole for South America: Northward continental motion in the Cenozoic, opening of Drake Passage and Caribbean convergence
title_sort eocene paleomagnetic pole for south america: northward continental motion in the cenozoic, opening of drake passage and caribbean convergence
url http://hdl.handle.net/20.500.12110/paper_21699313_v112_n3_p_Somoza
work_keys_str_mv AT somozar eocenepaleomagneticpoleforsouthamericanorthwardcontinentalmotioninthecenozoicopeningofdrakepassageandcaribbeanconvergence
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