Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia

Rare remnants of a Mesozoic subduction high pressure (HP) accretionary complex are exposed on Diego de Almagro Island in Chilean Patagonia. We herein focus on the Lazaro unit, a coherent slice of oceanic crust exposed on this island that has been first affected by high temperature (HT) metamorphism...

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Autores: Angiboust, Samuel, Hyppolito, Thais, Glodny, Johannes, Cambeses, Aitor, García-Casco, Antonio, Calderón, Mauricio, Juliani, Caetano
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2017
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/362140
Acceso en línea:http://hdl.handle.net/10261/362140
Access Level:acceso abierto
Palabra clave:Counter-clockwise P-T path
Hot subduction
Jurassic
Patagonia
Trondhjemite
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spelling Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean PatagoniaAngiboust, SamuelHyppolito, ThaisGlodny, JohannesCambeses, AitorGarcía-Casco, AntonioCalderón, MauricioJuliani, CaetanoCounter-clockwise P-T pathHot subductionJurassicPatagoniaTrondhjemiteRare remnants of a Mesozoic subduction high pressure (HP) accretionary complex are exposed on Diego de Almagro Island in Chilean Patagonia. We herein focus on the Lazaro unit, a coherent slice of oceanic crust exposed on this island that has been first affected by high temperature (HT) metamorphism followed by a lower temperature deformation event (LT). Its Pressure-Temperature-time (P-T-t) evolution is reconstructed using field and petrographic observations, phase relations, thermobarometry and geochronology. Remnants of a primary amphibolite to HP granulite-facies event in mafic rocks comprising garnet (with ilmenite exsolutions), diopside, trondhjemitic melt, pargasite, plagioclase ± epidote are reported for the first time in neosomes, indicating peak P-T conditions of 1.1–1.3 GPa and c. 750 °C. This peak T paragenesis has been thoroughly overprinted by a phengite-chlorite-actinolite assemblage during isobaric cooling down to c. 450 °C. U-Pb dating of zircon metamorphic rims from a metasedimentary rock yielded a homogeneous age population of 162 ± 2 Ma for the HT event. Sm-Nd dating of two peritectic garnet-bearing samples yield ages of 163 ± 2 Ma and 163 ± 18 Ma for the HT event. Multi-mineral Rb-Sr dating of a metasedimentary rock overprinted by LT deformation suggests retrograde shearing between 120 and 80 Ma. Our results show that the HT event in the Lazaro unit took place at around 160–165 Ma, shortly before the onset of Patagonian Batholith emplacement. Partial melting of subducted oceanic crust reported in the Lazaro unit is related to the early stages of hot subduction along the Gondwana western margin. The Lazaro unit remained at c. 40 km depth along the subduction interface for > 80 Ma, recording the deformation and long-term cooling of the subduction channel environment until the upper Cretaceous.Jesus Muñoz is acknowledged for field work assistance and discussions. Silvio Ferrero and Patrick O′Brien are acknowledged for insightful discussions and Philippe Yamato for sharing numerical modeling results. This project has been funded by a Deutsche Forschungsgemeinschaft (DFG) project to S.A. (AN1113-1), and São Paulo Research Foundation (FAPESP) (#2004/10203-7, #2012/01191-1) and received support for analytical costs at CIC from the University of Granada. T.H. acknowledges the grant #2014/23422-0 (FAPESP) for a post-doctoral fellowship and M.C. the Fondecyt grant #1161818. Arne Willner and Victor Ramos are fully acknowledged for insightful reviews on this manuscript. The journal editor Damian Nance is acknowledged for his careful editorial handling. This is IPGP contribution #3794. This is IBERSIMS publication n.36.Elsevier BVFundação de Amparo à Pesquisa do Estado de São PauloConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2024202420172024info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/362140reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1016/j.gr.2016.10.007Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3621402026-05-22T06:33:51Z
dc.title.none.fl_str_mv Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
title Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
spellingShingle Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
Angiboust, Samuel
Counter-clockwise P-T path
Hot subduction
Jurassic
Patagonia
Trondhjemite
title_short Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
title_full Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
title_fullStr Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
title_full_unstemmed Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
title_sort Hot subduction in the middle Jurassic and partial melting of oceanic crust in Chilean Patagonia
dc.creator.none.fl_str_mv Angiboust, Samuel
Hyppolito, Thais
Glodny, Johannes
Cambeses, Aitor
García-Casco, Antonio
Calderón, Mauricio
Juliani, Caetano
author Angiboust, Samuel
author_facet Angiboust, Samuel
Hyppolito, Thais
Glodny, Johannes
Cambeses, Aitor
García-Casco, Antonio
Calderón, Mauricio
Juliani, Caetano
author_role author
author2 Hyppolito, Thais
Glodny, Johannes
Cambeses, Aitor
García-Casco, Antonio
Calderón, Mauricio
Juliani, Caetano
author2_role author
author
author
author
author
author
dc.contributor.none.fl_str_mv Fundação de Amparo à Pesquisa do Estado de São Paulo
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Counter-clockwise P-T path
Hot subduction
Jurassic
Patagonia
Trondhjemite
topic Counter-clockwise P-T path
Hot subduction
Jurassic
Patagonia
Trondhjemite
description Rare remnants of a Mesozoic subduction high pressure (HP) accretionary complex are exposed on Diego de Almagro Island in Chilean Patagonia. We herein focus on the Lazaro unit, a coherent slice of oceanic crust exposed on this island that has been first affected by high temperature (HT) metamorphism followed by a lower temperature deformation event (LT). Its Pressure-Temperature-time (P-T-t) evolution is reconstructed using field and petrographic observations, phase relations, thermobarometry and geochronology. Remnants of a primary amphibolite to HP granulite-facies event in mafic rocks comprising garnet (with ilmenite exsolutions), diopside, trondhjemitic melt, pargasite, plagioclase ± epidote are reported for the first time in neosomes, indicating peak P-T conditions of 1.1–1.3 GPa and c. 750 °C. This peak T paragenesis has been thoroughly overprinted by a phengite-chlorite-actinolite assemblage during isobaric cooling down to c. 450 °C. U-Pb dating of zircon metamorphic rims from a metasedimentary rock yielded a homogeneous age population of 162 ± 2 Ma for the HT event. Sm-Nd dating of two peritectic garnet-bearing samples yield ages of 163 ± 2 Ma and 163 ± 18 Ma for the HT event. Multi-mineral Rb-Sr dating of a metasedimentary rock overprinted by LT deformation suggests retrograde shearing between 120 and 80 Ma. Our results show that the HT event in the Lazaro unit took place at around 160–165 Ma, shortly before the onset of Patagonian Batholith emplacement. Partial melting of subducted oceanic crust reported in the Lazaro unit is related to the early stages of hot subduction along the Gondwana western margin. The Lazaro unit remained at c. 40 km depth along the subduction interface for > 80 Ma, recording the deformation and long-term cooling of the subduction channel environment until the upper Cretaceous.
publishDate 2017
dc.date.none.fl_str_mv 2017
2024
2024
2024
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/362140
url http://hdl.handle.net/10261/362140
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1016/j.gr.2016.10.007
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier BV
publisher.none.fl_str_mv Elsevier BV
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,811543

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