Evolución paleogeográfica miocena en el sureste de la Depresión del Duero

Laburpena

The evolution of sedimentary environment during the Middle and Upper Miocene times at the southeastern region of the Duero Basin (Fig. 1) is dominated by the interrelation in space and time of three groups of facies: ALLUVIAL FANS attached to the mountainous Honrubia socle. FLUVIATILE placed just northwards from the former and LACUSTRINE-PALUDAL made up of carbonate sediments and placed at the edges of the two former facies (Fig. 2). The analysis of the distribution of fades leads to the distinction of three paleogeographic situations considered as end members and intermediate stages. Stage A (Fig. 3) shows the maximum extent of the alluvial and fluviatile realms related to the paleoreliefs placed toward the south and east respectively. Stage  (Fig. 4) represents the implantation of a lacustrine realm between the coalescent alluvial fans and the fluvial system that, consequently, is displaced towards the north. Stage C (Fig. 5) represents the maximum extension of the lacustrine realms that onlap the adjacent ones. These different models result from the variations of the balance between the surrection of the edges of the basin and the subsidence of the basin. Additional effects result from climatic gradients, affecting the erosional, depositional and postsedimentary processes.