El colapso BURATO ERGAP: Un rasgo morfo-tectónico de primera magnitud en el Banco de Galicia

Abstract

Multibeam and seismic data acquired during the ERGAP 1 and ERGAP 2 allowed the recognition and study of three big depressions which are located in the continental slope southeast of the Galicia Bank. These depressions correspond to collapses circular in shape that reach 370 m depth and whose size range between 2000 y 5000 m. Among them the so called BURATO ERGAPhave been analysed in detail. Seismic records from this depression indicate its erosive character, the occurrence of a diapirunderneath related to a shale layer, numerous faults that extend from the seafloor to the shale layer at both sides of the depression and finally and transparent seismic facies that could be associated to fluid venting. The genesis of this collapses must be explain in the framework of the Cenozoic Pyrenean compressive events, where faulting of the sedimentary cover over a viscous shale layer among other factors can be invoked to explain this outstanding features.