El sinclinal de Santo Domingo de Silos: Estratigrafía y paleogeografía de los sedimentos continentales (borde Este de la Cuenca del Duero)

Abstract

The materials of continental origin (Upper Cretaceous to Miocene) which constitute the Eastern area of the Duero Basin and its contact with the northern branch of the Iberian Massif (Province of Burgos) (Fig. 1) define two large sedimentary cycles (Fig. 2) temporally separated by tectonic and erosive processes. These began in the Upper Cretaceous (Senonense) and are represented by three depositional sequences (closely related to episodes of Alpine orogeny): pre-, sin- and post-tectonic. In them have been defined 14 lithostratigraphic Units (POL, C. 1985), with are range of Formations (Fig. 3). The syncline of Santo Domingo de Silos constitutes one of best outcrops of the first depositional sequence, owing to the existence of a continuous Upper Cretaceous (Senonense)-Paleogene continental series resting by net contact on the shallow marine sediments (barlagoon) corresponding to the end of the marine cycle of the Upper Cretaceous. These materials of the first deposition sequence, represented by the seven units described (Figs. 4 and 5), are composed of sediments of fluvio-lacustrian-palustrian origin which define a large negative megasequence mainly characterized by its alluvial members. This in turn is composed of four minor alluvial/lacustrian megasequences. The alluvial systems come from the ? and NE and increase their proximity with time, pointing to several tectonic pulses. Among these detritic units there are generalized rapid installation carbonated lacustrian episodes throughout the area, indicating the intervals of greatest stability (Fig. 6-14).