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Major changes in the Holocene were identified based on a diatom and geochemical analysis of sediment cores from Lakes Ufimskoe and Syrytkul (the Southern Urals). The Lake Ufimskoe ecosystem in the Central mountain area is identified to be highly sensitive to variations in temperature. Meanwhile, Lake Syrytkul is more responsive to climate aridization because of its limnological characteristics and less precipitation in the piedmont area. Climate events were the main drivers for lake ecosystems dynamics throughout almost the whole history of the lakes. The records of lake sediments reflect several climate events noted elsewhere in the Northern Hemisphere: Lateglacial–Holocene transition (~12,000–11,600), Preboreal oscillation (~11,200–11,000 cal. BP), climate warming and aridization (~9700–9600 cal. BP), warming and increase in precipitation since 9000 cal. BP, climate aridization at ~5800 cal. BP, cooling since 4000 cal. BP, and warming at ~2500 cal. BP. Climate warming of the last hundred years was not reflected in lake sediment records because of the significant human impact on the lake ecosystem. The upper sediments of both lakes are enriched in As, Bi, Sb, Te, Sn, Cd, Cu, Zn and Pb because of the influence of the Karabash copper smelter. However, the significant changes of the Lake Syrytkul ecosystem are not related to the technogenic impact and explained mainly by the dam construction. The changes in diatom communities identified in Lake Ufimskoe, which is located in an area geologically sensitive to acidification, are related to the acidification and heavy metal loading on the water area.

A high-resolution sediment core (MD95-2011) from the Vøring Plateau has been studied to document the variability of the surface water conditions during the Younger Dryas—Preboreal (13—9 kyr BP) in the eastern Norwegian Sea, in order to assess the climate variability in a period considered to be highly dynamic. Quantitative summer sea surface temperatures (SSSTs) with a time resolution of 20—40 years are reconstructed using three different diatom transfer function methods. The Younger Dryas—Preboreal transition at site MD95-2011 is documented with a temperature increase of 3.5°C/3°C within 100 years. Following, the record resolves for the first time PBO as two prominent cooling events centred at 11.2 and 11.3 kyr BP. In addition, a broad cooling event documented from 10.3—9.9 kyr BP coincides with previously documented climatic events as the 10.3 event and Erdalen Event 1 (10.1—9.9 kyr BP) and 2 (~9.7 kyr BP), respectively. Constrained by the observed SSST changes and diatom assemblages, short-term SSST changes with a periodicity of 80—120 years are observed, and the length of this period might indicate a possible connection to the solar Gleissberg cycle. The North Atlantic heat transport is highly sensitive to freshwater inputs, and the interplay of freshwater forcing with insolation forcing is considered as the controlling mechanism of climate changes at site MD05-2011 during the early Holocene. However, the century-scale variability of 80—120 years cannot explain the large-scale variability during the early Holocene, but is of importance for understanding the underlying small-scale oscillations.

This study attempts to reconstruct the Holocene glacier history of Breheimen, southern Norway from four stream-bank mire sites and a downstream lake sediment core near Sota Sæter, based on lithostratigraphy, sediment properties (loss-on-ignition (LOI), magnetic susceptibility (MS), grain size characteristics) and 69 radiocarbon dates. Late-Preboreal deglaciation is indicated by lake-floor accumulation of organic matter (gyttja) largely replacing minerogenic sediment before 9000 cal. BP. A distinct minerogenic layer is thought to represent glacier expansion during the 8.2 ka Finse Event. Following this event until c . 2200 cal. BP, glaciers were mostly smaller than today, indicated by slow accumulation of mainly gyttja with predominantly thin minerogenic layers. A trough in LOI and corresponding small peaks in different silt fractions indicate possible glacial expansion from c. 3500 to 3000 cal. BP. The shorter c. 7500 year stream-bank mire record suggests brief, distinct episodes of Neoglacial glacier activity at c. 5600 and 3650 cal. BP. After c. 2200 cal. BP, up to three possible glacier expansion events are indicated in the lake core compared with up to eight represented in the mire sequences, suggesting greater sensitivity of the latter to small-scale glacier expansion. Marked `suppressed' Neoglacial expansion until after c. 2200 cal. BP contrasts with the more typically reported start at 6000—5300 cal. BP elsewhere in southern Norway. Methodological implications are discussed including: factors responsible for erroneous radiocarbon dates in mire and lake core stratigraphies; high spatial variability in mire stratigraphy; determining the amplitude of glacier contraction episodes; isolating the glacial signal from background `noise'; and further improvement of dating.

A Holocene calcareous tufa deposit in the Fyledalen Valley in southern Sweden was investigated with respect to molluscs, pollen, plant macrofossils and Coleoptera remains. The investigation recovered four mollusc species that today are severely threatened and included in the Swedish Red List of Endangered Species and/or the European Community's Natura 2000 programme. These include Vertigo genesii (Gredler), Vertigo geyeri Lindholm, Cochlicopa nitens (Gallenstein) and Vertigo moulinsiana (Dupuy). Tufa formation was initiated in the early Preboreal (after 11 500 cal. BP), when an open birch-pine forest dominated the area and stopped in the late Boreal (after 8800 cal. BP) when deciduous trees had become established. The presence of the molluscan species Vallonia pulchella (Müller), Columella columella (Martens), Vertigo genesii, Pupilla muscorum (L.) and Euconulus alderi (Gray), coupled with an almost complete lack of shade-demanding taxa, suggests an open marsh environment throughout the time of tufa deposition. The mollusc succession shows evidence of increasing temperature. Columella columella, commonly associated with open arctic-alpine habitats is present at the base of the profile in the early Preboreal, whilst Vertigo genesii, which commonly is associated with open arctic-alpine habitats or calcareous springs, persists until the mid-Boreal (∼ 8800 cal. BP). The tufa deposition ends when the regional groundwater levels rise, approximately 8800 cal. BP, more thermophilous molluscs, such as Vertigo moulinsiana and V angustior Jeffreys and the aquatic Bithynia tentaculata (L.), Radix peregra (Müller) and Planorbis planorbis (L.) colonize the site. Stratigraphic correlations, as well as faunal and floral comparisons, are made with nearby sites.

10Be dating of a pronounced glacier advance (‘Kromer Stadial’) in the western part of the Silvretta Mountains (western Austria) yielded ages ranging from 8010±360 to 8690±410 years with a mean age for moraine stabilization of 8410±690 years. Hence, the Kromer Stadial, which was previously considered as early Preboreal, may represent the glacier response to the early phase of the ‘8.2-ka event’, as it is recorded in the Greenland ice-cores. The glacier advanced to a position beyond its ‘Little Ice Age’ (LIA) limit; the end moraines are situated 750-1000 m downvalley from the glacier ends in 1850. The corresponding drop of the equilibrium line altitude relative to the LIA datum was 75 m. The glacier advance was followed by a period of glacier recession and rock glacier development. In total, the climatic fluctuation may have lasted for about 500±200 years. The age and duration of the climatic fluctuation is in good accordance with the ‘Misox cold phase’ and CE-3 climatic fluctuation as recorded in Switzerland. Climate during the Kromer Stadial was characterized by more humid conditions than today along the northern fringe of the Alps and slightly negative to moderately positive changes in precipitation in the central part of the Austrian Alps. Summer temperatures changes were most likely in the order of-1 to OK. Mean annual temperature was 1.5K to 2K lower than today, at least during the second phase of the climatic fluctuation.

To reconstruct the vegetation history of the Upper Engadine, continuous sediment cores covering the past 11 800 years from Lej da Champfer and Lej da San Murezzan (Upper Engadine Valley, c. 1800 m a.s.l., southeastern Switzerland) have been analysed for pollen and plant macrofossils. The chronologies of the cores are based on 16 and 22 radiocarbon dates, respectively. The palaeobotanical records of both lakes are in agreement for the Holocene, but remarkable differences exist between the sites during the period 11 100 to 10 500 cal. BP, when Lej da Champfer was affected by re-sedimentation processes. Macrofossil data suggest that Holocene afforestation began at around 11400 cal. BP. A climatic deterioration, the Preboreal Oscillation, stopped and subsequently delayed the establishment of trees until c. 11000 cal. BP, when first Betula, then Pinus sylvestrislmugo, then Larix 300 years later, and finally Pinus cembra expanded within the lake catchment. Treeline was at c. 1500 m during the Younger Dryas (12 542- 11 550 cal. BP) in the Central Alps. Our results, along with other macrofossil studies from the Alps, suggest a nearly simultaneous afforestation (e.g., by Pinus sylvestris in the lower subalpine belt) between 1500 and 2340 m a.s.l. at around 11 400 to 11 300 cal. BP. We suggest that forest-limit species (e.g., Pinus cembra, Larix decidua) could expand faster at today's treeline (c. 2350 m a.s.l.), than 550 m lower. Earlier expansions at higher altitudes probably resulted from reduced competition with low-altitude trees (e.g. Pinus sylvestris) and herbaceous species. Comparison with other proxies such as oxygen isotopes, residual A14C, glacier fluctuations, and alpine climatic cooling phases suggests climatic sensitivity of vegetation during the early Holocene.

Reconstructions of mean July temperature (Tjul) and winter precipitation (Pw) for the last 11/500 years on the Folgefonna peninsula are presented. Tjul was reconstructed using pollen-climate transfer functions and Pw was reconstructed based on the exponential relationship between mean solid winter precipitation and ablation-season temperature at the equilibrium-line altitude (ELA) with a reconstructed former ELA, using Tjul as the proxy for ablation-season temperature. The reconstructions from the Folgefonna peninsula suggest that the early Holocene was relatively cool and dry until c. 8000 cal. yr BP, followed by a warm and humid mid-Holocene until c. 4000 cal. yr BP with inferred Tjul above 12°C and Pw reaching as high as 225% of the present day. Subsequent to c. 4000 cal. yr BP a reduction is seen in both inferred Tjul and Pw with large fluctuations during the last 500 years. In addition, new calculations of Pw from two glaciers (Hardangerjøkulen and Jostedalsbreen) in southern Norway are presented. The results show that Pw varied in phase at all glaciers, probably as a response to the same climate forcing factor. During the early Holocene a major shift is suggested between winds from the west and the east.

Travertines are carbonate deposits formed generally during temperate climatic periods. They usually present a succession of travertinous units and detrital sedimentary levels containing leaf impressions and charcoal, respectively. The travertine of St-Antonin was formed during the Holocence in accordance with this model; snail shells and archaeological material have also been preserved, essentially in detrital levels. An interdisciplinary investigation combining two palaeobotanical approaches (identification of leaf imprints and charred wood) has been carried out to identify vegetation changes, at a local or microregional scale during the travertine formation. Our results were compared with those of previous malacological, geomorphological and archaeological studies. The Preboreal and Boreal sequence of the travertine shows evidence of a reduction of the riverside vegetation correlated with the establishment of a mesophilous vegetation dominated by the pubescent oak (Quercus pubescens). During the Boreal–Atlantic transition, the vegetation structure changed slightly under anthropogenic influence. From the Atlantic to the first part of the Subboreal, vegetation seems to have been profoundly affected by intensive human exploitation. This process has broken up the forested area into different plant communities and favoured the dominance of heliophilous and thermophilous species.

Following the Younger Dryas, the first evidence of glacial activity in southern Norway in response to climatic change occurred during the early Holocene, when terminal moraines from the Erdalen Event formed beyond the position of later ‘Little Ice Age’ moraines. In front of present outlet glaciers on both sides of the Jostedalsbreen ice cap, sets of pre-‘Little Ice Age’ marginal moraines have been morphostratigraphically corre lated with the Erdalen Event. The lithostratigraphy in a peat bog at Hellemyrane in Jostedalen, western Norway, provides firm evidence for a two-phase Erdalen Event associated with two glacier readvances of Nigardsbreen at the Preboreal/Boreal transition. Radiocarbon dates from the peat bog give age estimates for the two phases: the first Erdalen Event readvance took place between 10 100 and 10 050 cal. BP, while the second occurred close to 9700 cal. BP. The lowering of the equilibrium-line altitude (ELA) during these readvances is estimated using the ‘Little Ice Age’ ratio (LR) approach to be about 230 m and 215 m, respectively. The first readvance is attributed to an increase in winter precipitation, while the second readvance may have been primarily caused by a marked drop in summer temperature which reactivated already existing ice masses.

After the pronounced fluictuation of 4‰ in δ18O during the Younger Dryas and the 1‰ dip during the Preboreal Oscillation, values for δ18O decreased very steadily from -2.5 to -5.3‰ from 9300 to about 800014C yr BP (uncal.). This early-Holocene decrease of almost3‰is interpreted as a result of a declinle of almost 6°C in the temperature of precipitation. The previous high temperature of much of the Lateglacial and the Preboreal (12000-9300 yr BP uncal.) may reflect warm summers related to greater insolation and warm winters caused by the influence of the Laurentide ice sheet on atmospheric circulation. After 8000 yr BP a disconformity interrupts the sequence, but after about 5000 yr BP the δ18O and δ13C are irregular because of a low lake level, as shown by the occurrence of littoral shells and woody detritus in the littoral core, and because of anthropogenic factors, as inferred from pollen indicators of forest disturbance and farming found in both the littoral and offshore cores.

Stratigraphy, radiocarbon dating and analyses of pollen, plant macrofossils and testate amoebae were used to reconstruct the development and ecology of a small raised bog in a karst-dominated landscape in the Swiss Jura Mountains. Special focus was on past vegetation and on the history of Pinus rotundata in relation to anthropogenic and climatic influences. Testate amoebae were used to reconstruc-t past local soil pH and water-table depth. The inferred development of the Praz-Rodet bog typifies a classic hydroseral tefrestrialization of a small basin. Two features are specific for this site. First, the bog was much wetter than today for a long period; according to our hypothesis, this only changed as a consequence of human activities. Second, two hiatuses are present at the coring location (Younger Dryas--early Preboreal, and 4700-2800 cal. yr BP), the former probably caused by low lake productivity due to cold temperatures and the latter by the erosional activity of the adjacent small river. The date of 2800 cal. yr BP for renewed peat accumulation may be related to climatic change (Subboreal-Subatlantic transition). Pollen indicators failed to show one hiatus: an apparently complete pollen sequence is therefore no guarantee of an uninterrupted sediment accumulation. Evidence of early minor human impact on the vegetation in the Joux Valley dates back to c. 6850 calendar years, congruous with the early Neolithic in the Jura Mountains. The history of Pinuis rotindata appears to be more complex than previously believed. Human activity is clearly responsible for the present abundance of this species, but the tree was naturally present on the bog long before the first evidence of important human disturbance of the site (1500 cal. yr BP). It is suggested that, in karst-dominated landscapes, dense forests growing on mineral soils around raised bogs may significantly reduce summer evapotranspiration by acting as windbreaks. Forest clearance results in increased evapotranspiration, causing a lowering of the water table on the bog and a modification of the vegetation cover. This hypothesis has implications for the management of similar small raised bogs in karst-dominated landscape.

The sedimentary record at Lake Vibysjo lake basin is situated close to the Närke Strait where the main water exchange occurred between the Vänern basin and Baltic basin during the middle and late phases of the Yoldia Sea stage of the Baltic Sea (c. 10 000– 9500 14C years BP). The area was deglaciated in a glaciomarine environment, as reflected by the occurrence of benthic calcareous fossils (foraminifera, ostracods and the mollusc Portlandia arctica (Gray)) in the lower-most clay units. The estimated date of deglaciation, 10 440 clay-varve years BP, suggests that a saline bottom-water current entered the Baltic basin shortly after the high areas south of Lake Vibysjön became free of ice. The brackish water fauna occurs during a regional Betula-Empetrum-Hippophaë pollen zone, which in southern Sweden is correlated with the early Preboreal. The isolation of the Lake Vibysjön basin is dated to 8100 14C years BP, and occurred during the last part of the Ancylus Lake stage. Based on investigations of other basins in Närke, it is concluded that the Mastogloia Sea reached c. 62 m a.s.l. and that the Litorina Sea reached at least 60 m a.s.l. in the area studied.

Marine sediments of about 116 m drilled onshore at Skagen near the northernmost tip of Jutland, Denmark, provides a continuous and detailed palaeoceanographic and palaeoenvironmental record of the last 11 000 14C years in the Skagerrak-Kattegat. The whole Younger Dryas was characterized by an arctic-subarctic environment where the North Jutland Current flows today, instead of being succeeded by a minor climate warming at about 10 600 BP as recorded in the southern Kattegat and in the areas strongly influenced by the Baltic Current and currents along the Swedish west coast. The changes in components of diatom assemblages, combined with previously published benthic foraminiferal data from the present core, reflect a two-step climatic warming and consequently environmental change during the transition from the Younger Dryas to the Preboreal. An abrupt warming of the sea surface waters took place at about 10 100 BP, which resulted from the inflow of warm Atlantic surface water. Summer sea-surface temperature rose about 8°C. It had a great influence on the surface water of the Skagerrak-Kattegat and shallow areas, but had only little effect on the bottom water in the deep parts of the region. Warming of bottom water occurred a few hundred years after the first warming, and is most likely simultaneous with the end of the Preboreal oscillation. A warm period at 7700-5100 BP is registered by diatom assemblages that resulted from the opening of the English Channel because of eustatic sea-level rise, and by larger influence of the Norwegian Coastal Current and currents along the Swedish west coast. A climate cooling was documented at about 5100 BP by acceleration of the South Jutland Current.

Neoglacial moraines that are substantially older than the conventional 'Little Ice Age' glacier maximum of the mid-eighteenth century have been recognized recently in the Sandane area of western Norway. This is important in the context of Scandinavian Holocene glacier variations because, in southern Scandinavia at least, it is widely accepted that glaciers were larger in the mid-eighteenth century than at any time since the Preboreal. In this report we question and test the age of supposed early 'Little Ice Age' and older Neoglacial moraines in two valleys in the Sandane area. Observations and data relating to moraine morphology, licheno metry and vegetation cover are reassessed and new lines of evidence based on boulder weathering (Schmidt hammer), soil development and glaciofluvial activity are introduced. Critical appraisal of the evidence leads to the conclusion that the existence of pre- or early 'Little Ice Age' moraines, dating from the thirteenth to seventeenth centuries (or, indeed, older Neoglacial moraines) cannot be supported. In Jardalen/Fagerdalen the evidence suggests only moraines of Younger Dryas and possibly Preboreal age; in Sørsendalen we recognize, in addition, a conventional 'Little Ice Age' moraine limit in front of Blåbreen.

Data on environmental change at the Younger Dryas-Preboreal transition and during the early Holocene are reviewed with particular reference to evidence from Poland and neighbouring areas of central Europe. Various factors modified the rate of environmental change during the general warming and reforestation. The preservation in central Europe of coniferous forest at the beginning of the Holocene, and the relatively late development of deciduous forest, were connected with the continuation of a continental climate until 9000-8500 BP. This is the main cause for a distinct division of the early Holocene into three phases: 1) 10 300-9500 BP; rapid warming, 2) Preboreal-Boreal continuous transformation 10 000-8500 BP; 3) change to oceanic climate 8700-7700 BP. During the 'Eoholocene' period, the various environmental systems - such as biological, aeolian, fluvial and lacustrine-exhibited diachronous evolution with different rates of change. The distinctive changes in central Europe are contrasted with other regions in the north-south European transect, taking into account such factors as substrate differences, plant migration rates and the pattern of deglaciation.