Características estratigráficas y estructurales del margen noroccidental del Sinclinorio de Truchas: geología aplicada a la prospección y explotación de pizarras para techar

Resumo

A new geological map of the Molinaferrera and Silván areas has been built up. The asea is located on the northern boundary of the Truchas Synclinorium (Hesperian Massif, West Asturian-Leonese Zone, NW Spain). The mapping interpretation, together with the information from more than 5,000 m of wireline logs has allowed the characterization of Luarca Slates and Agüeira Fm. in the E and W sector of the study area, as well as the definition of the more suitable horizons for the roofing slate. The potential exploitation of these horizons is also conditioned by their structural setting in the normal limb of the Truchas Synclinorium. This limb is more vertical toward the northern boundary, where it is overturned. The consequent formation of horizontal kink-bands severely limit the commercial utility of the slate. Other structures that limit the utility of the potentially exploitable slate are: a) sub-vertical kink bands locally developed and superposed 011 the horizontal kink bands; b) a sub-vertical joint set that presents a strike N15E and variable separation; c) creep slope processes affecting depths in excess of 200 m , possibly related to paleo-relief of Tertiary age.