Corte geológico y análisis estructural de pliegues relacionados con cabalgamientos de escala métrica en la Zona Cantábrica, NO de la Península Ibérica

Abstract

The studied structures are located in the northern limb of the Villasecino anticline (Cantabrian Zone). They are metre-scale structures developed in carboniferous limestone beds and its outcrop is set in a road slope. We applied a photogrammetric method to construct a geological cross-section without distortion and perpendicular to the structures. For this, we had to take 3 stereoscopic pairs of photographs, to obtain accurate coordinates of several control points on the outcrop photographed, to rectify the photographs in order to obtain stereoscopic pairs, to draw the geological interpretation of the 3D images and, lastly, to project the three-dimensional coordinates of the interpretation on a geological cross-section perpendicular to the folds axis and parallel to the tectonic transport direction. The outcrop shows faults sub-parallel to bedding and associated folds, as well as faults sub-perpendicular to bedding. We rotated the geological cross-section using the Villasecino anticline axis as the rotation axis and then we established a sequence of structures. Initially normal faults were originated, subsequently thrusts and related ramp folds were developed and, finally, the whole set was rotated and the normal faults worked as faults with a significant strike-slip component.