Abstract

METODIEV, D.; ROMAO, J.; DIAS, R.  and  RIBEIRO, A.. Vila Velha de Ródão syncline (Central-Iberian Zone, Portugal): lithostratigraphy, structure and evolutionary model of the Variscan tectonic. Comunicações Geológicas [online]. 2009, n.96, pp.5-18. ISSN 1647-581X.

The revision of the geological mapping (scale 1:25 000) of the Vila Velha de Ródão syncline revealed a succession whose data ranged from the early Ordovician to the lower Silurian, similarly to the D₃ Amêndoa-Carvoeiro sinform and new elements about the Variscan deformation. Early overthrusts, reactivated forethrusts with duplex geometry with NE facing, backthrusts and backfolds, folds with axial cleavage and linear structures were also observed; all of these deformation shows progressive character, in coaxial regime, resulted from the main phase D₁ of the Variscan orogeny. This deformation matches maximum NE-SW compression which can create thin-skinned décollement in depth and triangular structures of various scales. The syncline is located between two flower structures in regional scale and is affected by Variscan lateral ramps reactivated in dextral and sinistral strike-slip faults during the action of the late-Variscan episodes and of the Alpine orogeny.

Keywords : Lithostratigraphy; Ordovician; Silurian; Variscan deformation; forethrusts; backthrusts; triangular structure; late-Variscan strike-slip faults.

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