Desarrollo simultáneo de pliegues, esquistosidad y cabalgamientos en el Eoceno inferior de Isaba (Valle del Roncal, Pirineo Navarro)

• Autores: Andrés Gil Imaz
• Localización: Geogaceta, ISSN 0213-683X, Nº. 40, 2006, págs. 31-34
• Idioma: español
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• Resumen

  • Geometric and kinematic analysis of Pyrenean folds, cleavage and thrusts is carried out in several exceptional outcrops of the Eocene flysch at Isaba (Navarra, Spain). Distribution, orientation and cross-cut relationships between these structures suggest that they are roughly coeval and co-genetic, the total deformation being distributed into different ductile and brittle mechanisms. The footwall of the Sierra de Arrigorrieta thrust shows a set of harmonic folds with axial-plane cleavage; an overall flattening ll= 0,7-0,85 has been estimated from their profile-section geometry. The hanging-wall shows more heterogeneous deformation: minor thrusts, complex duplexes, and non-harmonic folds with sharp changes in orientation and density of cleavage linked to thrust ramps. The structural position and the presence of some cuspate-lobate folds (mullions) in turbidite levels suggest an early deformation even previous to the Larra thrust system.