The external high that separates the Colorado basin from the Argentine Basin has significant exploratory potential. In 2005, a 2.000 km2 3D seismic cube was recorded, covering a part of it. The interpretation of this cube revealed a polygonal fault system (PFS) that affects a discrete stratigraphic interval of Upper Cretaceous age (Campanian-Maastrichtian) exceeding the area of the cube, which suggests a great lateral continuity beyond the seismic data analyzed. This PFS affects a transgressive wedge in slope position, correlated with the Pedro Luro Formation defined at depth further west, it is characterized by a high density of normal faults with scarce displacement or slip with an almost isotropic orientation. In plant It has a polygonal honeycomb pattern with an average radius of 700 meters. Although it is superimposed on the regional faulting deformation regime that affects the sedimentary column in the area since the Upper Triassic, its origin seems not to be linked to tectonic processes. The upper limit of the zone affected by the PFS is a net contact, close to the Cretaceous-Cenozoic limit, with a stratigraphic interval composed of mass-transported sediment deposits (MTD) by gravitational processes and not affected by faulting. On the other hand, the lower limit is transitional since the thickness affected by the PFS varies between 100 and 250 meters and is not conditioned by variations in seismofacies or discrepancies. Moreover, there seems to be a direct correlation between the sedimentation rate associated with the pulses of the MTDs that overlay it and the thickness of the sedimentary column affected by the PFS. Other characteristics that seem to be necessary for its genesis (grain size and lithology) would be present in the sediments that host this PFS, Pedro Luro Formation, mainly composed of more than 350 meters of shales from a marine environment. Understanding the origin of this type of faulting can be key in certain petroleum systems as it could influence the geometry of the reservoirs, fluid distribution and efficiency of the seals. Its stratigraphic value as a correlation tool is also recognized for covering large areas and for the conditions necessary for its formation.