Erosion surfaces and Neogene landscape evolution in the NE Duero Basin (north-central Spain)

Abstract

We present a chronological model of erosion surface development in the Iberian and Cantabrian Ranges of north-central Spain. We map four erosion surfaces and interpret these to be related to Duero basin continental sediments and tectonic activity from Upper Oligocene to Plio-Pleistocene. The oldest erosion surface, SE1, formed across Upper Oligocene–Lower Miocene synorogenic deposits; while surface SE2 was contemporaneous with the Middle Miocene alluvial systems, ending with an uplift stage in the Astaracian. The two most recent erosion surfaces, SE3 and SE4, developed during extensional tectonic episodes and are associated with the deposition of Upper Páramo sedimentary units at the end of the Miocene (Upper Turolian) and alluvial fan deposits, known as rañas (Plio-Pleistocene). With the exception of SE1, which seems to be associated with a relatively wet climate, the surfaces formed during periods of marked aridity and generally warm temperatures. Through geostatistical reconstruction of the best preserved surface (SE2), applying ordinary kriging method to the topography (DEM) of the erosion surface and its correlating sedimentary plains, we identify the deformation processes which occurred on this surface after its formation.