Abstract

Climatic change in the western Mediterranean basin over the last 140 ka has been investigated from sediment and soil sequences along the coast of the northeastern part of Mallorca, Spain. Palaeoclimate and palaeoenvironments are reconstructed from sediment and soil structures, marine and terrestrial molluscan fauna, grain size distributions, mineral magnetics, sediment and soil chemistry, SEM and oxygen isotope values. Dating is by OSL and amino acid geochronometry along with marine molluscan faunal assemblages. All Oxygen Isotope stages and substages from OIS 6 to 1 are recorded. Mean annual temperatures (m.a.t.) of c. 19.2°C for the climatic optimum of the Last Interglacial compare with c. 17.3°C for the present, and are associated with high sea level, extensive woodland and stable soils, although wide temperature ranges are detected during this stage with values as low as c. 10.3°C. Through OIS 5d to 5a m.a.t. fluctuated from 8.2°C to 17.9°C. Low sea level, open vegetation, effective river activity and aeolian sand and dust deposition characterize 5d and 5b while relatively high sea-level and soil development on stable landscapes dominate OIS 5c and 5a. OIS 4 is represented by m.a.t. of c. 4.9°C with aeolian sand and loess deposition, limited river activity and weak soil development. Loess deposition persisted into OIS 3, but at this time the m.a.t. was c. 13°C and with higher humidity and vegetation growth. During the LGM (OIS 2) m.a.t. was c. 8.1°C and effective river, slope and aeolian processes, along with associated with limited vegetation cover, were responsible for the most extensive changes in the landscape. Major rates of change occur during periods of climatic deterioration when the high levels of geomorphic energy were imposed on a landscape undergoing a breakdown of vegetation cover.