Speleothems and palaeoclimate variability in western Iberia during the Last Glacial

<p>Large-scale and abrupt climate oscillations in the Northern Hemisphere, such as Heinrich Stadials and Dansgaard-Oeschger events, during the last glacial period have long been substantiated by marine and ice core records. Their effects on the continental setting however, specifically the Iberian Peninsula, are more ambiguous, as terrestrial records are sparse and / or discontinuous. The Iberian Peninsula is a key site for proposed late survival of Neanderthals in Europe and replacement by H. Sapiens. Many researchers have used marine records to suggest that the climatic fluctuations of Marine Isotope Stage 3 (MIS-3), specifically Heinrich Stadial 4 (HS-4), caused Neanderthal extinction ~38 ka. To further investigate the climatic aspect of Neanderthal demise, more local climate archives need to be employed. Our sites are situated on the Atlantic coast and central Portugal and should be sensitive to marine responses, such as sea surface temperature (SST) or source water composition. We employ speleothem based palaeoclimate reconstruction from two Portuguese sites with three specimens from Gruta Figueira Brava (Arrabida, Portugal) and two specimens from Almonda (Torres Novas, Portugal), spanning 68-22 ka. We create a high-resolution multi-proxy terrestrial palaeoclimate record that allows us to explore this time interval for extremes in climate transition / fluctuation. We find the transitional boundary between MIS-4 and MIS-3 via stable isotope and trace element data and identify dry phases of reduced precipitation coinciding with Heinrich Stadials. However, no extreme aridity events can be observed. We suggest that for our coastal site, moisture availability is unlikely to have played a major role in Neanderthal extinction during MIS-3.</p>