Stratigraphic signature of a terminal Early Cambrian regressive event in the Iberian Peninsula
In the Iberian Peninsula, the uppermost Lower Cambrian (early Bilbilian age) is represented by the deposition of conglomerates and sandstones, except in a northwestern region (the Cantabrian Mountains), where carbonate deposition took place. These coarse siliciclastic deposits indicate a regressive trend, called the Daroca regression. In its type area (the Iberian Chains, northeast Spain), this regressive episode represents a progradational highstand systems tract, which did not result in widespread subaerial exposure of the shelf. In addition, the absence of important stratigraphical gaps and the good biostratigraphical control based on trilobites and acritarchs in the Iberian Chains permit a correlation of this regressive trend with other neighboring areas, where the top of this trend is represented by a regional unconformity and a hiatus that began in the latest Early Cambrian and extended through early Middle Cambrian times.