El sinforme de Alcañices en la transversal de Manzanal del Barco

Abstract

The stratigraphy and structure of the Alcañices synform are described in the cross section of the Esla valley. The sedimentary succesion, ranging from the Lower Ordovician to the Devonian, has been divided in six formations, to which local denominations have been assigned. The structure is a rather complex one, resulting from the superimposition of four deformation phases of hercynian age and of a tardi-hercynian faulting stage. The first phase gave rise to large recumbent folds, the second was responsible for the appearance of subhorizontal shear zones and thrust faults, the third produced steep folds approximately homoaxial with the first ones, and the fourth generated a swarm of sinistral wrench faults trending NW-SE. The tardihercynian stage of faulting produced a new fault system trending NE-SW as well as new movements of the faults of the previous phase as dextral wrench ones.