Speleothem climate capture of the Neanderthal demise

The Iberian Peninsula is a region of climatic and archaeological interest as it lies upon the boundary between the North Atlantic and Mediterranean climatic zones and was the last refuge of the Neanderthals. The influence of climate changes on Neanderthal populations remains a mystery due to the lack of independently-dated high-resolution terrestrial records of past climate and environmental change from the Iberian Peninsula. The primary aim of this project was to construct a palaeoclimate record using speleothems from Matienzo, northern Iberia, across the period encapsulating the Neanderthal demise. Contemporary cave monitoring of Cueva de las Perlas has demonstrated the potential for speleothems to be used as indicators of past climate and environmental conditions. Assessment of cave dynamics through a comprehensive monitoring programme has classified the karst hydrology, cave ventilation, processes influencing speleothem growth and proxies preserved within speleothem calcite. Three speleothems were used to develop records of past climate and environmental variability between 90,000 and 30,000 years ago. A long-term aridity trend was evident throughout the record which is interpreted as a response to orbital-forcing. Sub-orbital climate instability was superimposed onto this long-term trend as evidenced through wet-dry proxies (δ18O, δ13C, Mg and Sr). Millennial-scale events coincident with the timing of North Atlantic Heinrich Events have been identified and the sub-orbital climate variability resembles that of North Atlantic Dansgaard-Oeschger cycles. Therefore, evidence from the speleothems demonstrates a tight coupling of the North Atlantic Ocean-Atmosphere system throughout MIS3. The Cueva de las Perlas speleothems have established that the period of the Neanderthal demise was characterised by climate instability involving abrupt shifts and millennial-scale events, thereby adding climatic pressures at a time of anatomically modern human appearance