Résumé
Marine palynomorph data paired with other indicators of sea-surface hydrography (planktic foraminiferal assemblages and oxygen isotopes) were used to decipher the impact of cold events on the northern Aegean region during the last glacial to interglacial transition. The data, which were derived from marine sediment cores GeoTu SL152 and GeoTu SL148, point to a strong impact of the Heinrich 1 and Younger Dryas cold events on surface-water conditions in the northern Aegean Sea. Shifts in marine palynomorph assemblages correlate with changes in terrestrial vegetation and climate (i.e. precipitation and temperature reconstructions based on pollen assemblages) in the northern borderlands of the Aegean Sea. The climate responses of the Aegean region to Heinrich event 1 (H1, ca. 17.5 to ca. 15.7 cal ka BP) and Younger Dryas (ca. 12.6 to ca. 11.7 cal ka BP) events appear similar in magnitude (with mean annual temperatures between similar to 6 and 10 degrees C and mean annual precipitation between similar to 300 and similar to 450 mm). However, the annual temperature decline during the H1 relative to the preceding already cold conditions was minor (<3 degrees C). The transition from the relatively warm and humid local equivalent of the Allerod interstadial to the Younger Dryas, on the other hand, witnessed an annual temperature decline of 6 C and an annual precipitation decrease of 300 mm, the latter occurring abruptly within only ca. 150 a. The return to warmer conditions in the northern Aegean region after the Younger Dryas was completed at ca. 11.6 cal ka BP. Copyright (C) 2011 John Wiley & Sons, Ltd.