The Aptian mixed carbonate and siliciclastic ramp of Castro Urdíales (Cantabria, Northern Spain)

Detailed geologic mapping and facies analysis of the Lower Aptian succession in the Castro Urdiales area led to the establishment of a mixed depositional system built of three different carbonate ramp units interlayered with two siliciclastic intraplatform trough units. Carbonate ramps characterized relative calm tectonic stages,whereas siliciclastic troughs developed during more active tectonic stages. Internally the analyzed interval contains two major sedimentary breaks, caused probably by relative sea-level falls of tectonic origi