Sedimentologia de la sucesión cretácica basal en el borde sur del Sistema Central (Madrid)

• Autores: José F. García-Hidalgo Pallarés, J. Gil, Manuel Segura Redondo
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 3, 2, 2001 (Ejemplar dedicado a: XIV Congreso Nacional de Sedimentología, IV Congreso del Cretácico de España), págs. 197-200
• Idioma: español
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• Resumen

  • 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.