A multidisciplinary overview of the lower Miño River terrace system (NW Iberian Peninsula)

Abstract

The Miño River basin represents one of the main fluvial catchments draining the Atlantic side of the Iberian Peninsula. The extensive sedimentary deposits of this basin have been documented since the 19th century, but limited research has been undertaken on these features historically, and the Quaternary record of the basin has remained understudied until recently. Research carried out over the last decade on the Spanish margin of the Miño River has enabled more detailed classification and mapping of the main fluvial landforms, as well as numerical (luminescence, electron spin resonance, cosmogenic) dating of some of the deposits associated with Palaeolithic archaeological sites. Here we synthesise the existing Quaternary fluvial record for the basin, and present new geospatial and chronological analyses for the lower catchment area. Our latest examination has enabled the identification of nine fluvial terrace levels and other regionally significant sedimentary features (e.g., alluvial fans) formed in response to tectonics, eustatic changes and associated global climate changes. The chronological data and calculated incision rates indicate that the various fluvial terraces were formed during the Early to Late Pleistocene. Numerous Palaeolithic sites have been found in association with the middle terrace levels (between +40 and +13 m above present-day river level). Primarily, these archaeological sites preserve assemblages that feature large flake Acheulean (LFA) tools, though a number of Middle Palaeolithic sites have also been documented. Direct dating of these sites, together with morphostratigraphic correlations across the terrace system, suggest that the basin has been extensively occupied by human populations during the last 300 thousand years.