Resumen
The southern foothills of the Fuegian Andes are bounded by the Beagle Channel (BC), a conspicuous
E-W longitudinal basin, controlled by a large transcurrent fault system, which extends from the Atlantic to the Pacific
Ocean. The northern shore of the Beagle Channel?s central segment is characterized by several E-W oriented valleys,
parallel to the main basin, which are interspersed with a series of oblique NW trending lineaments that extend across the
mountain belt. A geoelectrical survey was carried out in order to investigate the shallow architecture of such sets of linear
morphologies. The principal E-W lineament system was characterized by conspicuous sub-vertical resistivity contrasts,
interpreted as fractured zones associated with fault strands of the main strike-slip Beagle Channel system, whereas the
oblique NW-SE trending set of lineaments revealed slightly different resistivity patterns, with vertical displacements
and less abrupt contrasts. These resistivity patterns, in combination with the widespread occurrence of normal faulting
in the area, allowed to infer an extensional control over the oblique depressions. These morphological features were
related to oblique transverse faults that segment two sub parallel E-W fault systems. The oblique faults were probably
developed along inherited structural anisotropies and can be extended well beyond the BC shoreline to the NW. Both
geophysical and field evidence suggest a post-glacial deformation along the area