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We present distribution maps for all cryptotephras (distal volcanic ash layers) younger than 7 ka that have been reported from three or more lakes or peatlands in north-west Europe. All but one of the tephras originates from Iceland; the exception has been attributed to Jan Mayen. We find strong spatial patterning in tephra occurrence at the landscape scale; most, but not all of the tephra occurrences are significantly spatially clustered, which likely reflects atmospheric and weather patterns at the time of the eruptions. Contrary to expectations based on atmospheric modelling studies, tephras appear to be at least as abundant in Ireland and northern Scotland as in Scandinavia. Rhyolitic and other felsic tephras occur in lakes and peatlands throughout the study region, but andesitic and basaltic tephras are largely restricted to lake sites in the Faroe Islands and Ireland. Explanations of some of these patterns will require further research on the effects of different methodologies for locating and characterizing cryptotephras. These new maps will help to guide future investigations in tephrochronology and volcanic hazard analysis. Postprint

A new pollen record of the penultimate interglacial complex, corresponding approximately to marine isotope stage (MIS) 7 (ca 186,000–245,000 years before present), has been generated in core I-284 from the Ioannina basin in northwest Greece. It represents the highest resolution terrestrial record for this interval available to date, with a mean sampling interval of 200 years. The sequence records four forested intervals, correlated with MIS 7e, 7c, 7a and a sub-orbital-scale event following 7a but within MIS 7. The longest and most complete warm stage in terms of vegetational succession is MIS 7c, while the succession in MIS 7e appears to be truncated by a shift to colder, drier climatic conditions. The results of biomisation suggest that during all of these intervals winter temperatures in NW Greece remained lower than during the Eemian or Holocene, while smaller populations of sclerophyllous taxa indicate that summers may have been wetter. Intervening intervals of open vegetation are correlated with MIS 7d, 7b and an oscillation following 7a. Low tree pollen percentages during MIS 7d are interpreted as reflecting very cold and dry conditions, concomitant with a period of low northern hemisphere insolation which resulted from a rare combination of minimum obliquity and maximum precession. Higher tree pollen percentages throughout MIS 7b, by contrast, are indicative of relatively mild conditions, in agreement with marine temperature and ice volume records. Sub-orbital scale oscillations in tree population extent are also recorded in the new I-284 record suggesting that, just as in the last climatic cycle, NW Greece was affected by rapid climatic oscillations that are associated with changes in the North Atlantic.

Uncertainty as to the pattern of Lateglacial and early Holocene climate change in the western Balkans and Greece has persisted despite extensive investigation of the Ioannina I-284 lake–sediment sequence, northwest Greece. Here we present a new diatom record from I-284 for this time period. After dominance by eurytopic small Fragilariales, the Lateglacial Interstadial (ca 14.9–12.7 cal kyr BP) is marked clearly by a relative increase in planktonic Cyclotella ocellata. A return to small Fragilariales from ca 12.7 to 11.6 cal kyr BP approximately coincides with the Younger Dryas chronozone. It is followed by a major transition to dominance by Cyclotella spp. at the Pleistocene–Holocene boundary. We interpret these shifts as a response to both lake level and productivity change induced by shifts in effective moisture and temperature, demonstrating that the diatom record provides the first strong evidence for a Younger Dryas event in northwest Greece, and for both warming and wetting during the Lateglacial interstadial and early Holocene. We also present clear evidence for an abrupt phase of catchment instability during the early Holocene. In this case we must await the results of further research to test whether it was driven by climatic or tectonic forcing.

This study centres on palaeoenvironmental analysis of the upper part of a long core from the partially drained, tectonic Ioannina basin, north-west Greece. The data span the Lateglacial and Holocene and comprise pollen, mollusc, magnetic susceptibility, loss-on-ignition and particle size analyses. These augment previously published ostracod and stable isotope data from the same sediment sequence. The age model for the sequence is based on 19 AMS dates, five of which were obtained using a novel procedure for the separation of microcharcoal from sediment. The pollen data suggest that although temperate woodland expanded at the beginning of the Lateglacial, only limited woodland contraction occurred during the Younger Dryas chronozone, despite strong evidence for a sharp drop in sea surface temperature in the neighbouring Adriatic at this time. In contrast, large-scale vegetational and sedimentological changes occur in concert during the Holocene, some of which may be ascribed to human impact. Comparison with other records from the Ioannina basin suggests that previous, more littoral pollen sequences did not constitute a wholly representative record of Lateglacial and Holocene vegetational change.