Publication: Revisión de la geocronología U-Pb de las carbonatitas del NW de Fuerteventura: nuevos datos e implicaciones geológicas
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2016
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Sociedad Geológica de España.
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Abstract
En este trabajo se presentan nuevas edades U-Pb en circones de carbonatitas del sector NW de Fuerteventura. Los circones presentan características tanto texturales como composicionales que indican su origen ígneo y su cristalización a partir de magmas carbonatíticos. La edad obtenida, 24.2 ± 0.3Ma, es algo más joven que la existente para las carbonatitas del sector centro-occidental de la isla, por lo que se propone que habrían existido al menos dos intrusiones alcalino-carbonatíticas con cierta migración temporal en el sentido SW-NE, dentro de una zona de rift. Esta edad, además, restringe el episodio magmático alcalino-carbonatítico de la isla a prácticamente 1 Ma de duración. Sin embargo, este lapso temporal es significativo, en cuanto que representa la consecuencia de los cambios que ha sufrido la placa africana en su movimiento de divergencia con respecto a América del Sur y de convergencia con Eurasia.
In this work, new U-Pb zircon ages in carbonatites from the NW sector of Fuerteventura are presented. The zircons show textural and compositional characteristics indicating its igneous origin and its crystallization from carbonatitic magmas. The obtained age, 24.2 ± 0.3 Ma, is slightly younger than the existing age for carbonatites in the central-western sector of the island. Therefore, we propose that at least two alkaline- carbonatitic intrusions would have been emplaced in a rift zone, with a certain degree of time migration from SW to NE. In addition, this age constrains the alkaline-carbonatitic magmatic episode in the island to an almost virtually 1 Ma span. However, this time lapse is meaningful, as it represents the consequence to the changes underwent by the African plate in its divergent movement with respect to South America and its convergence with Eurasia.
In this work, new U-Pb zircon ages in carbonatites from the NW sector of Fuerteventura are presented. The zircons show textural and compositional characteristics indicating its igneous origin and its crystallization from carbonatitic magmas. The obtained age, 24.2 ± 0.3 Ma, is slightly younger than the existing age for carbonatites in the central-western sector of the island. Therefore, we propose that at least two alkaline- carbonatitic intrusions would have been emplaced in a rift zone, with a certain degree of time migration from SW to NE. In addition, this age constrains the alkaline-carbonatitic magmatic episode in the island to an almost virtually 1 Ma span. However, this time lapse is meaningful, as it represents the consequence to the changes underwent by the African plate in its divergent movement with respect to South America and its convergence with Eurasia.