Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics

New insights on the Paleozoic evolution of the continental crust in the North Patagonian Massif are presented based on the analysis of Sm-Nd systematics. New evidence is presented to constrain tectonic models for the origin of Patagonia and its relations with the South American crustal blocks. Geolo...

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Autores principales: Martínez Dopico, C.I., López de Luchi, M.G., Rapalini, A.E., Kleinhanns, I.C.
Formato: JOUR
Materias:
Argentina
Crustal units
Gondwana
North Patagonian Massif
Sm-Nd isotope systematics
collision zone
continental crust
isotopic composition
magmatism
Paleozoic
rifting
samarium-neodymium dating
tectonic evolution
tectonic structure
Patagonia
Antonia
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_08959811_v31_n2-3_p324_MartinezDopico
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_08959811_v31_n2-3_p324_MartinezDopico
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spelling todo:paper_08959811_v31_n2-3_p324_MartinezDopico2023-10-03T15:42:59Z Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics Martínez Dopico, C.I. López de Luchi, M.G. Rapalini, A.E. Kleinhanns, I.C. Argentina Crustal units Gondwana North Patagonian Massif Sm-Nd isotope systematics collision zone continental crust Gondwana isotopic composition magmatism Paleozoic rifting samarium-neodymium dating tectonic evolution tectonic structure Argentina Patagonia Antonia New insights on the Paleozoic evolution of the continental crust in the North Patagonian Massif are presented based on the analysis of Sm-Nd systematics. New evidence is presented to constrain tectonic models for the origin of Patagonia and its relations with the South American crustal blocks. Geologic, isotopic and tectonic characterization of the North Patagonian Massif and comparison of the Nd parameters lead us to conclude that: (1) The North Patagonian Massif is a crustal block with bulk crustal average ages between 2.1 and 1.6Ga TDM (Nd) and (2) At least three metamorphic episodes could be identified in the Paleozoic rocks of the North Patagonian Massif. In the northeastern corner, Famatinian metamorphism is widely identified. However field and petrographic evidence indicate a Middle to Late Cambrian metamorphism pre-dating the emplacement of the ca. 475Ma granitoids. In the southwestern area, are apparent 425-420Ma (?) and 380-360Ma metamorphic peaks. The latter episode might have resulted from the collision of the Antonia terrane; and (3) Early Paleozoic magmatism in the northeastern area is coeval with the Famatinian arc. Nd isotopic compositions reveal that Ordovician magmatism was associated with attenuated crust. On the southwestern border, the first magmatic recycling record is Devonian. Nd data shows a step by step melting of different levels of the continental crust in the Late Palaeozoic. Between 330 and 295Ma magmatism was likely the product of a crustal source with an average 1.5GaTDM (Nd). Widespread magmatism represented by the 295-260Ma granitoids involved a lower crustal mafic source, and continued with massive shallower-acid plutono volcanic complexes which might have recycled an upper crustal segment of the Proterozoic continental basement, resulting in a more felsic crust until the Triassic. (4) Sm-Nd parameters and detrital zircon age patterns of Early Paleozoic (meta)-sedimentary rocks from the North Patagonian Massif and those from the neighboring blocks, suggest crustal continuity between Eastern Sierras Pampeanas, southern Arequipa-Antofalla and the northeastern sector of the North Patagonian Massif by the Early Paleozoic. This evidence suggests that, at least, this corner of the North Patagonian Massif is not allochthonous to Gondwana. A Late Paleozoic frontal collision with the southwestern margin of Gondwana can be reconcilied in a para-autochthonous model including a rifting event from a similar or neighbouring position to its post-collision location. Possible Proterozoic or Early Paleozoic connections of the NPM with the Kalahari craton or the western Antartic blocks should be investigated. © 2010 Elsevier Ltd. Fil:Martínez Dopico, C.I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Rapalini, A.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_08959811_v31_n2-3_p324_MartinezDopico
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Argentina
Crustal units
Gondwana
North Patagonian Massif
Sm-Nd isotope systematics
collision zone
continental crust
Gondwana
isotopic composition
magmatism
Paleozoic
rifting
samarium-neodymium dating
tectonic evolution
tectonic structure
Argentina
Patagonia
Antonia
spellingShingle Argentina
Crustal units
Gondwana
North Patagonian Massif
Sm-Nd isotope systematics
collision zone
continental crust
Gondwana
isotopic composition
magmatism
Paleozoic
rifting
samarium-neodymium dating
tectonic evolution
tectonic structure
Argentina
Patagonia
Antonia
Martínez Dopico, C.I.
López de Luchi, M.G.
Rapalini, A.E.
Kleinhanns, I.C.
Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics
topic_facet Argentina
Crustal units
Gondwana
North Patagonian Massif
Sm-Nd isotope systematics
collision zone
continental crust
Gondwana
isotopic composition
magmatism
Paleozoic
rifting
samarium-neodymium dating
tectonic evolution
tectonic structure
Argentina
Patagonia
Antonia
description New insights on the Paleozoic evolution of the continental crust in the North Patagonian Massif are presented based on the analysis of Sm-Nd systematics. New evidence is presented to constrain tectonic models for the origin of Patagonia and its relations with the South American crustal blocks. Geologic, isotopic and tectonic characterization of the North Patagonian Massif and comparison of the Nd parameters lead us to conclude that: (1) The North Patagonian Massif is a crustal block with bulk crustal average ages between 2.1 and 1.6Ga TDM (Nd) and (2) At least three metamorphic episodes could be identified in the Paleozoic rocks of the North Patagonian Massif. In the northeastern corner, Famatinian metamorphism is widely identified. However field and petrographic evidence indicate a Middle to Late Cambrian metamorphism pre-dating the emplacement of the ca. 475Ma granitoids. In the southwestern area, are apparent 425-420Ma (?) and 380-360Ma metamorphic peaks. The latter episode might have resulted from the collision of the Antonia terrane; and (3) Early Paleozoic magmatism in the northeastern area is coeval with the Famatinian arc. Nd isotopic compositions reveal that Ordovician magmatism was associated with attenuated crust. On the southwestern border, the first magmatic recycling record is Devonian. Nd data shows a step by step melting of different levels of the continental crust in the Late Palaeozoic. Between 330 and 295Ma magmatism was likely the product of a crustal source with an average 1.5GaTDM (Nd). Widespread magmatism represented by the 295-260Ma granitoids involved a lower crustal mafic source, and continued with massive shallower-acid plutono volcanic complexes which might have recycled an upper crustal segment of the Proterozoic continental basement, resulting in a more felsic crust until the Triassic. (4) Sm-Nd parameters and detrital zircon age patterns of Early Paleozoic (meta)-sedimentary rocks from the North Patagonian Massif and those from the neighboring blocks, suggest crustal continuity between Eastern Sierras Pampeanas, southern Arequipa-Antofalla and the northeastern sector of the North Patagonian Massif by the Early Paleozoic. This evidence suggests that, at least, this corner of the North Patagonian Massif is not allochthonous to Gondwana. A Late Paleozoic frontal collision with the southwestern margin of Gondwana can be reconcilied in a para-autochthonous model including a rifting event from a similar or neighbouring position to its post-collision location. Possible Proterozoic or Early Paleozoic connections of the NPM with the Kalahari craton or the western Antartic blocks should be investigated. © 2010 Elsevier Ltd.
format JOUR
author Martínez Dopico, C.I.
López de Luchi, M.G.
Rapalini, A.E.
Kleinhanns, I.C.
author_facet Martínez Dopico, C.I.
López de Luchi, M.G.
Rapalini, A.E.
Kleinhanns, I.C.
author_sort Martínez Dopico, C.I.
title Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics
title_short Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics
title_full Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics
title_fullStr Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics
title_full_unstemmed Crustal segments in the North Patagonian Massif, Patagonia: An integrated perspective based on Sm-Nd isotope systematics
title_sort crustal segments in the north patagonian massif, patagonia: an integrated perspective based on sm-nd isotope systematics
url http://hdl.handle.net/20.500.12110/paper_08959811_v31_n2-3_p324_MartinezDopico
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AT rapaliniae crustalsegmentsinthenorthpatagonianmassifpatagoniaanintegratedperspectivebasedonsmndisotopesystematics
AT kleinhannsic crustalsegmentsinthenorthpatagonianmassifpatagoniaanintegratedperspectivebasedonsmndisotopesystematics
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