Artículo
High-pressure/low-temperature metamorphism in the collision zone between the Chilenia and Cuyania microcontinents (western Precordillera, Argentina)
Fecha de publicación:
12/2016
Editorial:
Pergamon-Elsevier Science Ltd
Revista:
Journal of South American Earth Sciences
ISSN:
0895-9811
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
In central-western Argentina, an Early Paleozoic belt including mafic-ultramafic bodies, marine metasedimentary rocks and high-pressure rocks occur along the western margin of the Precordillera and in the Frontal Cordillera. First pressure-temperature estimates are presented here for low-grade rocks of the southern sector of this belt based on two metasedimentary and one metabasaltic sample from the Peñasco Formation. Peak metamorphic conditions resulted within the range of 345–395 °C and 7.0–9.3 kbar within the high-pressure greenschist facies. The corresponding low metamorphic gradient of 13 °C/km is comparable with subduction related geothermal gradients. Comparison between these results and data from other localities of the same collision zone (Guarguaraz and Colohuincul complexes) confirms a collision between Chilenia and the composite margin of western Gondwana and suggests a stronger crustal thickening in the south of the belt, causing exhumation of more deeply buried sequences. During the Early Paleozoic a long-lived marine sedimentation coupled with the intrusion of MORB-like basalts occurred along a stable margin before the collision event. This contrasts with the almost contemporaneous sedimentation registered during accretion in accretionary prism settings and additionally proves the development of a collision zone along western Precordillera and the eastern Frontal Cordillera as well as the existence of Chilenia as a separate microcontinent.
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Articulos(IDEAN)
Articulos de INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Articulos de INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Citación
Boedo, Florencia Lucila; Willner, A. P.; Vujovich, Graciela Irene; Massonne, H. J.; High-pressure/low-temperature metamorphism in the collision zone between the Chilenia and Cuyania microcontinents (western Precordillera, Argentina); Pergamon-Elsevier Science Ltd; Journal of South American Earth Sciences; 72; 12-2016; 227-240
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