Late Quaternary landscapes of the Portuguese Estremadura: environmental change during Marine Isotope Stages 3 and 2.
Presentation
Overview
Overview
Description
Evidence from the Estremadura coast of central Portugal shows widespread landscape instability coincident with Neanderthal occupation during Marine Isotope Stage 3 (MIS3). Two sea level high stands during this period are preserved in uplifted coastal sediments in various tectonic settings between Peniche and São Pedro de Muel. The beach deposits, dated by radiocarbon and luminescence methods, likely correlate with the Denekamp and Hengelo interstadials found elsewhere in northern and western Europe. Mousterian artifacts including stone tools, flakes, and cores are found within the lower beach complex, in foredune or tidal flat sands in close lateral association with organic-rich lagoon and channel fill deposits (~41,000 BP). The artifact-bearing sands are topped by overwash storm deposits and cross-bedded beach sand facies related to the second high stand (~33,000 BP). The coastal sequences are buried by an aeolian sand sheet that extends up to 15 km inland. Luminescence ages imply that the sand sheet was emplaced by ~27,000 BP. Thick fills in coastal-draining river floodplains and a diapiric valley paralleling the coast suggest very high rates of upland erosion around the same time. Following deposition, the valley fills were reworked by aeolian activity and later trenched during the sea level low stand of the glacial maximum (MIS2). These findings highlight the magnitude of geomorphic response to climatic instability during MIS3, which was probably responsible for as much landscape change as the more commonly-cited extreme aridity during the glacial maximum. They also provide paleoenvironmental context for the newly-discovered Mousterian sites in the region.
