Insights into the structural evolution of the pre-Variscan rocks of the Eastern Pyrenees from La Molina quartz veins; constraints on chlorite and fluid inclusion thermometry
González-Esverit, E. (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Canals i Sabaté, Àngels (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Casas Tuset, Josep Maria (Universitat de Barcelona. Departament de Dinàmica de la Terra i de l'Oceà)
Nieto García, Fernando Javier (Universidad de Granada. Departamento de Mineralogía y Petrología)

Date:	2020
Abstract:	Quartz veins hosted in the infra and overlying series to the (Sardic) Upper Ordovician Unconformity provide new insights into the structural and thermal evolution of the pre-Variscan rocks of the Eastern Pyrenees. In the La Molina area (Canigó massif), two generations of metric quartz veins (V1 and V2) are distinguished by their distribution patterns and their relationships to the deformational macro, meso, and microstructures. P-T formation conditions are obtained by combining chlorite geothermometry and fluid inclusion microthermometry data. Discrepancy on formation temperature for chlorites located at different positions within the veins are discussed, concluding that veins grew in a low fluid/rock ratio regime. V1 veins can be related to the Late Ordovician syn-sedimentary faulting episode as revealed by their distribution patterns, formation mechanisms, and fluid-rock interactions. We propose an Alpine age for the V2 veins, based on their structure and the emplacement conditions of 318 ± 12°C and 2. 4 ± 0. 2kbar, with an estimated geothermal gradient of 34°C∙km-1 and a burial depth of ca. 9km. Results obtained here are compared with other quartz veins spread throughout the Paleozoic basement of the Eastern Pyrenees.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Quartz veins ; Pyrenees ; P-t conditions ; Chlorite
Published in:	Geologica acta, Vol. 18 (2020) , p. 1-XVIII (Articles) , ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/376973
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2020.18.18
DOI: 10.1344/GeologicaActa2020.18.18

38 p, 6.8 MB

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