Resumen de Sedimentologia de la sucesión cretácica basal en el borde sur del Sistema Central (Madrid)
José F. García-Hidalgo Pallarés, J. Gil, Manuel Segura Redondo
Terrigenous sediments forming the base of the Cretaceous succession at the south of the Central System (central Spain) form a transgressive-regressive cycle, that can be divided into three depositional sequences. The base o f the Atienza sequence is composed offluvialf-coastal deposits, an erosion surface separates these sediments from the overlying low-energy coastal association bearing root traces (rhizolites), which probably reflect the presence of emersion processes at the sequence boundary. Patones sequence is composed of 5 shallowing-upwards parasequences, formed mainly by shoreface-offshore facies associations in which alternate low-energy (offshore grey to black, glauconite-rich, muds) and high-energy deposits (cross-bedded sands with hummocky cross stratification). Finally, the Molar sequence is composed of three parasequences; the main facies associations are a shoreface association where cross-bedded and massive sands of beach aspect, prevails, a shoreface-offshore association, and a tidal association with stromatolitic dolostones and burrowed clays bearing rhizoliths suggesting the presence of emersion events related to the top of the T-R cycle.
