Una visión actualizada de la distribución de los materiales preordovícicos de la Zona Centro Ibérica meridional

The southern boundary of the Central Iberían Zone is discussed and undoubtedly located in the "Los Pedroches" axis for Precambrian and Cambrian times. We have studied the pre-Ordovician rocks on a 200 km long band immedíately bounding thís axis and 60 km wide differentiating three main units below the Armorican Quartzite: Lower Alcudian, Upper Alcudian and Basal Ordovician. Our work is mainly focussed on Upper Alcudían subdívided in three units separated by unconformities and discontinuities. The first one AS1 is entirely uppermost Proterozoic, AS2 corresponds to the Lowermost Cambrian and AS3 is a well-dated Lower Cambrian. The purpose of this work is to review every zone where the Upper Alcudian rocks outcrop beca use many of them were absolutely unknown, some other were considered as Ordovician in the existing maps, and the age of the well-known outcrops is discussed. Their distribution is depicted on an actualized map