Estuarine facies in the LateAlbian ofCabo Quintres (Cantabria, Basque-Cantabrian Región)

The Late Albian siliciclastic series of Cabo Quintres (Bielba'Formation) display an internal stratigraphic architecture made up of lithosomes of sandstones and silty mudstones up to ten metres thick and more than one hundred metres wide. They are arranged in coarsening and thickening upward successions bounded by marine flooding surfaces, representing the advance and return of estuarine channels on estuary-mouth subtidal areas. Croups of these successions are bounded by marine flooding surfaces (characteristics of parasequences) which present hardground development and high grade of bioturbation. Those groups are considered to have formed in response to events of transgression and regression. The Rio Miera palaeogeographic deep-structure, situated to the west of the studied area, was responsible for a greater subsidence to the east (Cabo Quintres), and possibly caused relative sea-level rising pulses in the area, which were in the origin of the parasequence