Artículo
Dating the Triassic continental rift in the southern Andes: the Potrerillos Formation, Cuyo Basin, Argentina
Fecha de publicación:
09/2008
Editorial:
Universidad de Barcelona
Revista:
Geologica Acta
ISSN:
1695-6133
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
The Triassic successions of western Argentina commonly show thin pyroclastic levels intercalated within thick fluvial and lacustrine terrigenous deposits. The Potrerillos Formation is the thickest Triassic unit in the Cuyo Basin. It is composed of alternating cycles of gravelly- sandy- and muddy-dominated intervals, in which several laterally-continuous tuff horizons occur. U-Pb SHRIMP ages were determined on zircon grains from three tuff levels located between the lowermost and the middle sections of the Potrerillos Formation. The ages for the time of deposition of the tuffs are 239.2 ± 4.5 Ma, 239.7 ± 2.2 Ma and 230.3 ± 2.3 Ma (Middle Triassic). Chemical data indicate that these acid to intermediate volcaniclastic rocks are derived from coeval basic magmas displaying tholeiitic to slightly alkaline signatures. They are associated with the rift stage that followed the extensive post-orogenic volcanism of the Choiyoi Group, that in turn has been ascribed to slab break-off in neighbouring areas. Two of the studied samples also record a subpopulation of inherited zircon grains with crystallisation ages of 260-270 Ma. The latter are considered to be an indirect measurement for the age of the Choiyoi Group in the Cuyo basin. The rift-related Triassic event represents the culmination of the Gondwanian magmatic cycle, and is interpreted as the result of subduction cessation and anomalous heating of the upper mantle previous to the western Gondwana break-up.
Palabras clave:
Triassic
,
Cuyo Basin
,
Argentina
,
U-Pb Zircon Dating
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - LA PLATA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos(CIG)
Articulos de CENTRO DE INVEST.GEOLOGICAS (I)
Articulos de CENTRO DE INVEST.GEOLOGICAS (I)
Citación
Spalletti, Luis Antonio; Fanning, Christopher Mark; Rapela, Carlos Washington; Dating the Triassic continental rift in the southern Andes: the Potrerillos Formation, Cuyo Basin, Argentina; Universidad de Barcelona; Geologica Acta; 6; 3; 9-2008; 267-283
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