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Líneas de Investigación:

MATERIALES Y PROCESOS GEOLÓGICOS

El objetivo principal de esta línea de investigación persigue elaborar un modelo de evolución tectonomagmática y de las interacciones manto-corteza durante la transición del ciclo Varisco al ciclo Alpino en las Cadenas Pirenaica e Ibérica.

Para ello, se realizan estudios integrado de los datos petrológicos, geoquímicos y tectónicos de los magmatismos tardi-variscos y mesozoicos en las Cadena Pirenaica e Ibérica.

Resultados destacados:

Hydrothermal macroscopic Fe-sepiolite from Oujda Mounts (Middle Atlas, Eastern Morocco). E. Arranz, M. Lago, J. Bastida, C. Galé, J. Soriano and T. Ubide. Journal of African Earth, Sciences, 52 (3): 81-88 (2008).

Abstract: The Triassic–Jurassic series in the Oujda Mounts (Middle Atlas, NE Morocco) includes two basaltic units. The whole sequence is crosscut by veins filled with Fe-sepiolite + chalcedony + calcite + smectite and mixed layer talc-saponite. Fe-sepiolite occurs as macroscopic fibres and is one of the latest mineral phases in the filling sequence of the veins.

The compositional relationships and crystallographic parameters obtained on carefully selected samples of sepiolite are compared with previous data, and support the actual development of Mg–Fe substitution in this clay mineral, given the adequate hydrothermal conditions.

Genesis of this uncommon variety of sepiolite in veins is interpreted as the result of regional low temperature hydrothermalism that affected the Middle Atlas during the Jurassic. The Mg-rich hydrothermal solutions interacted with the basaltic sequences, previously affected by alteration processes, producing the mobilization of Fe and allowing for the precipitation of Fe-sepiolite as a late mineral in the veins. (-> artículo completo)

Permian magmatism and basin dynamics in the southern Pyrenees: a record of the transition from late Variscan transtension to early Alpine extension: M. Lago, E. Arranz, A. Pocoví, C. Galé and A. Gil-Imaz. Geological Society of London, Sp.publications, 223: 439-464 (2004).

Abstract: Permian magmatism in the Pyrenees is characterized by two compositionally different and temporally consecutive magmatic episodes: a calc-alkaline-transitional phase (andesites) and a midly alkaline phase (basalts and dolerites).

These two magmatic episodes were related to the attenuation of late Variscan transtensional tectonics and the onset of extension related to regional rifting.

The strike-slip fault systems that affected the Pyrenees in late Variscan times initially controlled the development and morphology of the sedimentary basins. These were periodically affected by phases of extension, which controlled the subsidence of the basins, and, in addition, the emplacement of magmas.

The whole-rock trace-element and isotopic signature of the andesites suggests that they were derived from the upper mantle and variably hybridized with late orogenic crustal melts, whereas the alkali basalts could have been derived from a lithospheric mantle source, enriched as a consequence of Variscan subduction processes with the contribution, in some areas, of an enriched (asthenospheric) component. (-> artículo completo)

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