Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)

In the eastern part of the central Patagonian Cordillera (45°15-45°40S), northeast of the town of Coihaique, the chronology of volcanic sequences are documented by detailed field work and twelve new K-Ar dates that have established their Late Cretaceous-(?)Paleogene age. The oldest sequence corres...

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Autores principales:	Demant,Alain, Suárez,Manuel, De la Cruz,Rita
Lenguaje:	English
Publicado:	Servicio Nacional de Geología y Minería (SERNAGEOMIN) 2007
Materias:	Volcanism Patagonian Andes Upper Cretaceous K-Ar ages Petrochemistry
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082007000100001
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spelling	oai:scielo:S0716-020820070001000012007-04-19Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)Demant,AlainSuárez,ManuelDe la Cruz,Rita Volcanism Patagonian Andes Upper Cretaceous K-Ar ages Petrochemistry In the eastern part of the central Patagonian Cordillera (45°15-45°40S), northeast of the town of Coihaique, the chronology of volcanic sequences are documented by detailed field work and twelve new K-Ar dates that have established their Late Cretaceous-(?)Paleogene age. The oldest sequence corresponds to the rhyolitic and rhyodacitic domes of the Casa de Piedra Volcanic Complex, of Campanian age, which were emplaced on volcanic rocks of the Aptian-(?) Albian Divisadero Formation. The plagioclase and two pyroxenes andesitic to dacitic lavas of the El Toro Formation and the basalts from Morro Negro have a similar Maastritchian age. However, dacitic lavas with chemical signature similar to that of El Toro Formation crop out below the Morro Negro sequence showing that the basalts were the latest erupted lavas. Petrologic and geochemical data are used to characterize the three volcanic episodes. The Casa de Piedra volcanic rocks and the andesitic to dacitic lavas of the El Toro Formation have the mineralogy and geochemical signature of subduction-related magmas: enrichment in light rare earth elements (LREE), highly incompatible elements (Rb, Th, U and K), and strong depletion in Nb-Ta. Basalts from Morro Negro show distinct REE and multi-element patterns. Their geochemical signature is similar to that of the Murta Quaternary basalts, inferred to be related to slab window opening, but distinct from that of the Eocene Balmaceda basalts, more akin to within-plate volcanisminfo:eu-repo/semantics/openAccessServicio Nacional de Geología y Minería (SERNAGEOMIN)Revista geológica de Chile v.34 n.1 20072007-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082007000100001en10.4067/S0716-02082007000100001
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Volcanism Patagonian Andes Upper Cretaceous K-Ar ages Petrochemistry
spellingShingle	Volcanism Patagonian Andes Upper Cretaceous K-Ar ages Petrochemistry Demant,Alain Suárez,Manuel De la Cruz,Rita Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)
description	In the eastern part of the central Patagonian Cordillera (45°15-45°40S), northeast of the town of Coihaique, the chronology of volcanic sequences are documented by detailed field work and twelve new K-Ar dates that have established their Late Cretaceous-(?)Paleogene age. The oldest sequence corresponds to the rhyolitic and rhyodacitic domes of the Casa de Piedra Volcanic Complex, of Campanian age, which were emplaced on volcanic rocks of the Aptian-(?) Albian Divisadero Formation. The plagioclase and two pyroxenes andesitic to dacitic lavas of the El Toro Formation and the basalts from Morro Negro have a similar Maastritchian age. However, dacitic lavas with chemical signature similar to that of El Toro Formation crop out below the Morro Negro sequence showing that the basalts were the latest erupted lavas. Petrologic and geochemical data are used to characterize the three volcanic episodes. The Casa de Piedra volcanic rocks and the andesitic to dacitic lavas of the El Toro Formation have the mineralogy and geochemical signature of subduction-related magmas: enrichment in light rare earth elements (LREE), highly incompatible elements (Rb, Th, U and K), and strong depletion in Nb-Ta. Basalts from Morro Negro show distinct REE and multi-element patterns. Their geochemical signature is similar to that of the Murta Quaternary basalts, inferred to be related to slab window opening, but distinct from that of the Eocene Balmaceda basalts, more akin to within-plate volcanism
author	Demant,Alain Suárez,Manuel De la Cruz,Rita
author_facet	Demant,Alain Suárez,Manuel De la Cruz,Rita
author_sort	Demant,Alain
title	Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)
title_short	Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)
title_full	Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)
title_fullStr	Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)
title_full_unstemmed	Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)
title_sort	geochronology and petrochemistry of late cretaceous-(?)paleogene volcanic sequences from the eastern central patagonian cordillera (45°-45°40's)
publisher	Servicio Nacional de Geología y Minería (SERNAGEOMIN)
publishDate	2007
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082007000100001
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Geochronology and petrochemistry of Late Cretaceous-(?)Paleogene volcanic sequences from the eastern central Patagonian Cordillera (45°-45°40'S)

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