40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia

This paper presents the first argon dating of blueschists from the Jambaló area (Cauca Department) in the Central Cordillera of the Colombian Andes. Step-heating 40Ar/39Ar spectra were obtained for mica from several lenses of blueschists including greenschist facies rocks. The blueschists are mainly...

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Detalhes bibliográficos
Autores: Bustamante, Andrés, Juliani, Caetano, Hall, C. M., Essene, E. J.
Formato: artículo
Fecha de publicación:2011
País:España
Recursos:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:89014
Acesso em linha:https://ddd.uab.cat/record/89014
https://dx.doi.org/urn:doi:10.1344/105.000001697
Access Level:acceso abierto
Palavra-chave:Blueschists
Colombian Andes
Jambaló area
40Ar/39Ar geochronology
id ES_01d48959cd6eaeaa46cebd4ec182401e
oai_identifier_str oai:ddd.uab.cat:89014
network_acronym_str ES
network_name_str España
spelling 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia implications on the styles of accretion in the Northern Andes Bustamante, Andrés Juliani, Caetano Hall, C. M. Essene, E. J. Blueschists Colombian Andes Jambaló area 40Ar/39Ar geochronology This paper presents the first argon dating of blueschists from the Jambaló area (Cauca Department) in the Central Cordillera of the Colombian Andes. Step-heating 40Ar/39Ar spectra were obtained for mica from several lenses of blueschists including greenschist facies rocks. The blueschists are mainly constituted of preserved lenticular cores in strongly mylonitic rocks, which resulted from retrometamorphic processes that affected the high pressure rocks during their exhumation. The majority of 40Ar/39Ar data points to metamorphic ages close to 63±3Ma, but some ages are older than 71Ma. These Maastritchtian-Danian ages correspond to the timing of exhumation of the blueschists near metamorphic peak conditions, because the dated paragonite and phengite crystallized during development of the mylonitic foliation. The continuous exhumation of this blueschist belt between 71-63Ma reflects the flow on an accretionary system/subduction channel environment that was interrupted by the collision of an intra-oceanic arc with the continental margin. Regional geological correlations suggest that this arc-continent collision also took place in Ecuador. This collisional event, although synchronous with other arc-continent collisions in the Northern Andes, was apparently not related to the formation of the great Caribbean arc, but to an arc built in the southeastern margin of the Caribbean plate. https://ddd.uab.cat/record/89014 https://dx.doi.org/urn:doi:10.1344/105.000001697
title 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
spellingShingle 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
Bustamante, Andrés
Blueschists
Colombian Andes
Jambaló area
40Ar/39Ar geochronology
title_short 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
title_full 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
title_fullStr 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
title_full_unstemmed 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
title_sort 40Ar/39Ar ages from blueschists of the Jambaló region, Central Cordillera of Colombia
author Bustamante, Andrés
author_facet Bustamante, Andrés
Juliani, Caetano
Hall, C. M.
Essene, E. J.
author_role author
author2 Juliani, Caetano
Hall, C. M.
Essene, E. J.
author2_role author
author
author
topic Blueschists
Colombian Andes
Jambaló area
40Ar/39Ar geochronology
topic_facet Blueschists
Colombian Andes
Jambaló area
40Ar/39Ar geochronology
description This paper presents the first argon dating of blueschists from the Jambaló area (Cauca Department) in the Central Cordillera of the Colombian Andes. Step-heating 40Ar/39Ar spectra were obtained for mica from several lenses of blueschists including greenschist facies rocks. The blueschists are mainly constituted of preserved lenticular cores in strongly mylonitic rocks, which resulted from retrometamorphic processes that affected the high pressure rocks during their exhumation. The majority of 40Ar/39Ar data points to metamorphic ages close to 63±3Ma, but some ages are older than 71Ma. These Maastritchtian-Danian ages correspond to the timing of exhumation of the blueschists near metamorphic peak conditions, because the dated paragonite and phengite crystallized during development of the mylonitic foliation. The continuous exhumation of this blueschist belt between 71-63Ma reflects the flow on an accretionary system/subduction channel environment that was interrupted by the collision of an intra-oceanic arc with the continental margin. Regional geological correlations suggest that this arc-continent collision also took place in Ecuador. This collisional event, although synchronous with other arc-continent collisions in the Northern Andes, was apparently not related to the formation of the great Caribbean arc, but to an arc built in the southeastern margin of the Caribbean plate.
publishDate 2011
format article
url https://ddd.uab.cat/record/89014
https://dx.doi.org/urn:doi:10.1344/105.000001697
language eng
eu_rights_str_mv openAccess
institution Universitat Autònoma de Barcelona
collection Dipòsit Digital de Documents de la UAB
reponame_str Dipòsit Digital de Documents de la UAB
instname_str Universitat Autònoma de Barcelona
_version_ 1878430756284399616
publishDateSort 2011
author_browse Bustamante, Andrés
Essene, E. J.
Hall, C. M.
Juliani, Caetano
score 6,924472

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