Devonian of the Aran Valley Synclinorium, Central Pyrenees, Spain: stratigraphical and paleontological data

Abstract

In the Aran Valley Synclinorium, situated in the Axial Zone of the Pyrenees, a Devonian succession crops out. This succession has been studied in three localities, two on its southern limb and one on the northern one. These series can be correlated and show the sharp lithological changes occurring in the Devonian of this area, with a predominance of sandstones towards the North and an important development of limestones towards the South. The paleontological study has allowed, on the basis of conodonts, to date several  levels in the two sections on the southern limb; in one of them the Middle- Upper Devonian boundary has been traced fairly accurately. Anomalous faunal distributions have been detected in some of the successions and it is suggested that they are related to the existence of thrusts. However, other processes such as folding or sedimentary reworking, cannot be rejected.