Resumen de Depósitos arenosos de un delta tipo Gilbert en el Urgoniano de Laga (Bizkaia): Facies y procesos sedimentarios.
Luis M. Agirrezabala Mundiñano, Joaquín García Mondéjar
Sand andsilt deposits of a fluvial-dominated Gilbert type delta corresponding to an Urgonian mixed platform are described and interpreted. Their outcrop in Laga beach (Bizkaia) allows the recognition of 10 sedimentary facies and the construction of a 70 m long and 77.5 m high detailed cross-section, showing the typical tripartite depositional geometry. Topset deposits are horizontally bedded fluvial sandstones with internal trough cross-stratification. Foreset deposits, up to 28° dip, are composed of interbedded sandstones and fallout siltstones; sandstones were deposited by supercritic flows (chutes-and-pools, antidunes and plane beds) and gravity flows (sand flows, slumps, slides and creep?). Bottomset deposits, up to 5° dip, are composed of fallout siltstones and turbiditic sandstones. The development of the delta was related with active tilting.
