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This paper discusses the results of siliceous microfossils studies performed in a “staircase” of four isolation basins (33.7 m–2.9 m a.s.l.) on Big Solovetskiy Island (Solovki Archipelago, the White Sea). Diatoms were used as a primary group for paleoinferences, while chrysophyte cysts and sponge spicules also demonstrated high indicative potential. In all study lakes, the siliceous microfossils stratigraphy revealed three main stages of their evolution, i.e. large-basin, transitional and small-lake stages, each characterized by certain composition of the diatom assemblages and floristic diversity, relative abundances of chrysophyte cysts and sponge spicules, and siliceous microfossils concentrations. In the uppermost lake, glaciolacustrine environments unfavorable for aquatic biota existed during the large-basin stage. The proglacial lake stage terminated prior to ca. 10.4 cal ka BP, followed by a (semi)terrestrial episode before the transition to small-lake environments. In the other three lakes, marine environments were inferred at the earlier stage, characterized by the predominance of marine and brackish-marine diatoms, increased proportions of sponge spicules and low “cysts to diatoms” ratio. At the transitional marine-freshwater stage, mass growth of small fragilarioid diatoms and decreased abundances of spicules indicated unstable environments, while increased proportions of cysts pointed to progressive freshening of the basins. The duration of the marine-freshwater transition expectedly prolonged from ca. 200 yr in the upper basin (16.6 m a.s.l) to ca. 500 yr in the lowermost lake (2.9 m a.s.l.). The isolation from the sea took place between ca. 6.3 and 1.4 cal ka BP. At the small-lake stage, siliceous microfossils stratigraphies reflected local specifics of the basins and their catchments. We argue that besides traditionally used diatom data, relative and absolute abundances of siliceous microfossils also possess high indicative value for isolation basin studies. Our study demonstrated that marine waters on Big Solovetskiy Island never reached ca. 34 m a.s.l. during the Holocene, unlike the western coast of the Onega Bay where the Preboreal marine intrusion was recorded even at higher elevated localities. Different rates and amplitudes of shoreline displacement are thus suggested for the inner and outer parts of the Onega Bay. During the mid-Holocene Tapes transgression, before ca. 6.3 cal ka BP, the relative sea level on Big Solovetskiy Island exceeded 17 m a.s.l. The average estimated rates of the shoreline retreat during the second half of the Holocene gradually decreased from 0.28 cm year−1 to 0.2 cm year−1, indicating slowed isostatic uplift.

In the granitic part of the eastern Massif Central (France), the Gourd des Ailleres (GDA) mire provides one of the only Late-Glacial and Early Holocene sequences with a continuous sedimentation since the Oldest Dryas around 16000 years calibrated Before Present (16 ka cal. BP). Bioclimatic and hydrological changes were reconstructed based on sedimentological parameters, as well as by means of plant and animal macrofossils, pollen, and diatoms analyses through time. The environmental history of this site started with a small lake formed behind a moraine-dam. The multi-proxy study of the sedimentary sequence demonstrated that the coldest conditions took place around 14.3 ka cal. BP, at the very end of the Oldest Dryas. The Bolling period (14.2–13.9 ka cal. BP) was obviously warmer than the Allerod period (13.9–12.8 ka cal. BP) in the Monts du Forez Mountains. However, both chronozones presented a short cooling phase: the Intra Bolling Cold Period (IBCP) and the Intra Allerod Cold Period (IACP), respectively. The Older Dryas (14–13.9 ka cal. BP) was identified for the first time in this region based on pollen and diatom indicators. Thereafter, the Younger Dryas (12.9–11.7 ka cal. BP) was characterised by major temperature fluctuations. Windy conditions prevailed as indirectly demonstrated by the high frequency of Aulacoseira diatoms in the sequence. The onset of the Holocene was dated to 11.7 ka cal. BP. Peat-forming processes started thereafter due to the quick postglacial warming and the former GDA lake finally evolved into a limnogenous mire at the end of the Preboreal (10.4 ka cal. BP).

The Holocene has always been considered a crucial epoch where the major cultural steps of humankind took place. Understanding past Holocene climatic variability, shifts in vegetation, and faunal communities are among crucial challenges in predicting the upcoming changes of the natural environment. In Central Europe, the Krakow-Czestochowa Upland is one of the best study areas for detecting faunal, environmental, and climate shifts. For that reason, we choose to study the small vertebrate and mollusc communities of three archaeological sites with Holocene horizons: Sąspowska Zachodnia Cave, Ciasna Cave, and Male Rockshelter. We analysed the faunal community shifts, and we compared our results with the major Holocene sites in the area with the correspondence and cluster analyses. The environment and climate were reconstructed through Habitat Weighting, Quantified Ecology, malacological spectra and Bioclimatic methods. Environment and climate values showed a temporary replacement of the Late Glacial tundra and grasslands with boreal forest mixed with open wetlands during the Preboreal and then stable landscapes dominated by temperate forests. Models based on rodent data show that temperature and precipitation generally increased, starting from the Boreal, to reach values near, or sometimes overwhelm, the current climate values of the area during the Atlantic and Subboreal. The climate values obtained from herpetofaunal analyses show very slight changes between the Preboreal and the Atlantic (Ciasna Cave layers 3 and 4), except for the winter temperatures, whereas results obtained for Sąspowska Zachodnia Cave are probably biased by a very low number of recovered remains. Among rodents, a major negative oscillation detected in layers related to the edge of Early Holocene was related to the Preboreal Oscillation or long-lasting effect of the Younger Dryas.

Lateglacial and Holocene sandy aeolian sequences with palaeosol horizons located in different sedimentary zones in western-central Poland were analysed in order to establish their regional stratigraphical and palaeoenvironmental significance. Results of sedimentological, geomorphological and absolute dating methods from 3 representative profiles from an extraglacial zone (Leszczyca site), a glaciomarginal zone (Barczyglow site) and a glaciated zone (Godzieba site) are presented. A compilation of 31 luminescence dates from aeolian sands and 7 14C-dates from palaeosols formed the basement for establishing the stratigraphic position of the analysed deposits. The obtained results were correlated with reference to Greenland ice-core chronology, which has the best resolution for the Northern Hemisphere. In the extraglacial zone, aeolian deposition started in the Oldest Dryas and continued throughout the Older Dryas (main phase of dune built) with limited deposition in the Younger Dryas and finished in Preboreal. Aeolian deposition was interrupted by pedogenic processes in the Bolling and Allerod interstadials as well as in the Younger Dryas-Preboreal transition. Whereas in the glaciomarginal zone aeolian deposition started in the Younger Dryas and continued to the Early Boreal with a weakly expressed pedogenic process in the Early Preboreal. In the glaciated zone, aeolian deposition took place in the Younger Dryas. At the Barczyglow and Godzieba sites palaeosols of the Roman Period and 19th century were detected, covered by aeolian sands. The Subatlantic aeolian episodes were induced by human activity and registered forest fires. Identified periods of aeolian activity and pedogenic processes were correlated with other profiles from central and western Europe.

In the northern part of the Polish Outer Western Carpathians, the Beskid Makowski Mts., four landslides formed during the Late Glacial have been identified, so far. Within the depositional sequences (organic-mineral) of fens occurring in landslide depressions, palaeoenvironmental changes of the Late Glacial and the Holocene are recorded. The oldest of fen, started to form in the Oldest Dryas Stadial, the younger ones – in the Bolling Interstadial (two fens) and in the Older Dryas Stadial. The thickness of fen deposits varies from 1.5 m to 4.5 m. The sediments deposited in the Late Glacial represent long sequences (reaching 50–80% of the profile), whereas the Holocene deposits are reduced here due to the occurrence of long-lasting sedimentation gaps (hiatuses). The reconstruction of palaeoenvironment was carried out on the basis of pollen and lithological (loss on ignition, areometric) analyses along with more than 45 14C datings. In the Late Glacial sequences of the examined logs, mineral horizons interlaying organic deposits were affected by periodic climate warmings resulting in the permafrost melting during the Bolling and the Allerod Interstadials. In the Late Glacial deposits there are sequences (ca 0.5 m thick) deposited during the Older Dryas Stadial. The Allerod in the analyzed logs is bipartite: the lower sections (AL-1) are usually represented by peat deposition, whereas in the upper parts of the logs (AL-2) numerous minerogenic (clay, silty clay) inserts confirm the climate humidity growth (or permafrost melting) during the Gerzensee Oscillation. In the Late Glacial deposits, pollen of thermophilous trees, such as Corylus, Tilia, Quercus, Carpinus, as well as (typical for the Subboreal Phase) Abies alba and Fagus sylvatica occur, which may indicate the presence of thermophilous refugia in this part of the Carpathians. During the middle part of the Younger Dryas Stadial climate cooling, the widespread gradual increase in the delivery of allochthonous material to fens is related to permafrost melting. This process is finished by the deposition of clay and silty clay horizon at the beginning of the Holocene (Preboreal). The lack of the depositional sequences of the Boreal, Atlantic and partly the Subboreal phases in the majority of the logs is caused by the erosional removal of sediments during the climate humidity growth at the beginning of the Subboreal and the Subatlantic phases.

7th International Anthracology Meeting, University of Liverpool, UK, 2-6 Sept. 2019; International audience; Previous methodological developments in the field of anthracology have led to the definition of rigorous sampling methods in archaeological contexts, which provide highly accurate and reliable taxonomic frequency spectra as a basis for understanding past woodland vegetation. However, the fuelwood taxon frequency spectra represent a synthetic picture of forest composition in the environs of an archaeological site. Our aim in this paper is to describe the heterogeneity of woodland distribution. The Abeurador cave (Hérault) in the south of France, has previously provided an exceptionally rich palaeoecological study. We further explore the spatial frequency distributions of the charcoal taxa found in charcoal scatters from two layers dated to the Mesolithic (Preboreal). The frequencies of abundant taxa have a unimodal distribution in the sampled grid squares, close to the normal distribution. The ratio s2/m (variance/mean) termed the ‘distribution index’, estimates the regularity of distribution of each taxon in the grid squares. We hypothesized that the frequency distribution of a taxon in a layer could be considered to be its statistical sampling distribution (i.e. probability distribution) in the firewood collection catchment at a given time, since the quantity of this taxon fluctuates in each firewood assemblage according to its probability of collection, relating to its distribution heterogeneity (or accessibility) in the past environment. The distribution index was then used to estimate the heterogeneity of the palaeoenvironmental distribution of each taxon and thus its random, uniform or clustered distribution. On this basis, we propose a mapped restitution of the evolution of the main woodland species in the surroundings of the Abeurador during the Early Holocene, integrated with the whole sequence dynamics.; Les développements méthodologiques précédents de l'anthracologie ont conduit à la définition de méthodes d'échantillonnage rigoureuses en contexte archéologique, fournissant des spectres de fréquences taxonomiques précis et fiables comme base pour la compréhension de la végétation forestière passée. Les spectres de fréquence des taxons dans le bois de feu représentent une image synthétique de la composition des forêts aux alentours d'un site archéologique. Notre objectif dans cet article est de décrire l'hétérogénéité de la distribution des forêts. La grotte de l'Abeurador (Hérault), dans le sud de la France, a déjà fourni une étude paléoécologique exceptionnellement riche. Nous étudions ici la distribution spatiale, par mètre carré, des fréquences des taxons dans les charbons de bois dispersés de deux couches datant du Mésolithique (Préboréal). Les fréquences des taxons abondants ont une distribution unimodale dans les carrés de la grille d'échantillonnage, proche de la Loi normale. Le rapport s2/m (variance/moyenne), ou "index de distribution", estime la régularité de la distribution des fréquences de chaque taxon dans les carrés de la grille. Nous émettons l'hypothèse que la distribution de fréquence d'un taxon dans une couche pouvait être considérée comme sa distribution d'échantillonnage statistique (c'est-à-dire sa distribution de probabilité) dans l'aire de collecte du bois de feu à un moment donné, puisque la quantité de ce taxon fluctue dans chaque assemblage de bois de feu en fonction de sa probabilité de collecte, liée à son hétérogénéité de distribution (ou d'accessibilité) dans l'environnement du site. L'index de distribution est utilisé pour estimer l'hétérogénéité de la distribution paléoenvironnementale de chaque taxon et donc son patron de distribution aléatoire, uniforme ou groupée. Sur cette base, nous proposons une restitution cartographiée de l'évolution des principales espèces forestières dans les environs de l'Abeurador au cours de l'Holocène précoce, interprétée en fonction de la dynamique forestière de l'ensemble de la séquence.

On the basis of statistical analysis of craniometric data relating to Mesolithic and Neolithic samples from northern Eurasia, we discuss the peopling of the Baraba forest-steppe in the Early Holocene. This region is represented by samples from Sopka-2/1 (early sixth millennium BC), Protoka (late fifth to early fourth millennia BC), Korchugan (early-mid sixth millennium BC), and Vengerovo-2A (late sixth millennium BC). The results of the principal component analysis are interpreted in the context of debates over the role of autochthonous traditions in the Neolithic. During the Preboreal period (10 ka BP), large parts of the Baraba forest-steppe were flooded by the transgression of lake systems during climatic warming. This may have caused depopulation, lasting for at least a millennium. The Early Holocene people of Baraba were an offshoot of Meso-Neolithic populations of the northwestern Russian Plain. On that basis, the Early Neolithic populations of Baraba were formed. Direct population continuity is traceable only through the Chalcolithic. Since the late sixth millennium BC, however, the local population had incorporated migrants from the Pit-Comb Ware area in the central Russian Plain and, indirectly (via the Neolithic Altai), from the Cis-Baikal area.

Soft-sediment deformation structures have been indentified in glaciolacustrine deposits of the terrace complexes of the Lake Imandra (Kola Region, NE of the Fennoscandian Shield). According to the paleoseismological criteria, we found that these deformation structures were induced by strong earthquakes. These earthquakes led to the occurrence of secondary deformations of various morphology and sizes in the sandy-sandy sediments, forming a single complex consisting of intensely deformed and destructed deposits and associated clastic dikes and cracks. Among the plastic deformations, the phenomena of liquefaction, boudinage structures, flame structures, irregular convolute stratifications, diapir-like structures and synsedimentary folds are developed. Among brittle deformations, cracks and micro-fractures and dykes, predominate. The spatial and stratigraphic distributions of soft-sediment deformation structures were used to infer about the activation of faults during the Late Glacial and Postglacial period of the sub-latitudinal and north-western strike directions that limit the different-scale blocks of the earth’s crust. According to radiocarbon analysis data and paleogeographic reconstructions, the formation of soft-sediment deformations took place at the end of the Young Dryas – the beginning of the Preboreal period between 12900–11500 cal yr BP, and later, in the Preboreal period – beginning of the Boreal period between 11500– 9900 cal yr BP. It was this period that was accompanied by increased seismic activity not only in the Kola region, but also in the whole of Fennoscandia.

In this paper we present the chronological, environmental and climatic data obtained by analysing the remains of rodents collected from the water-screened sediments of Levels 2 and 3 of the Sector Entrada of Toll Cave (Moià, Barcelona), one of the caves belonging to the karstic system called the Coves del Toll. From these levels a total of 216 rodent remains have been recovered, corresponding to 10 rodent species. The biochronological results indicate a Late Pleistocene/Holocene chronology (13 ka BP), and Level 2 is probably Holocene (

The results of studies of the Late Pleistocene and Holocene spore–pollen spectra and the microtheriofauna of loose deposits of four cave localities located in the Shchuger and Kozhym river basins within the territory of the Yugyd-Va National Park on the western slope of the Subpolar Urals are discussed. Assessment of the age of sediments from the karst cavities was based on the data of AMS radiocarbon dating of mammalian bones. The speleogenic formations of the localities studied contain layers assigned to the final stage of the degradation of the Polar Ural (Late Valdai) glaciation (Middle to Late Dryas) and to the Preboreal, Boreal, and Subatlantic periods of the Holocene. Cryoxerophilous tundra species predominated (88.3%) in the fossil microtheriofauna assemblage identified for the Allerod. The Middle Dryas and Allerod, the cold and warm periods of the Late Glacial, respectively, were reflected by the spore–pollen spectra. The microtheriofauna on the western slope of the Subpolar Urals remained quite cryophilous by the end of the Late Dryas. The broad distribution of yernik thickets and goosefoot–gramineous–mixed herb assemblages during that time has been established. The vegetation of the western foothills of the Subpolar Urals consisted of grass–shrub tundra with sparse spruce trees during the Late Preboreal cooling period. The microtheriofauna community also had a tundra-like composition. The presence of dark coniferous taiga forests in the south of the Subpolar Urals and sparse spruce–birch forests with pine and dwarf birch in the undergrowth in the north of the area during the Boreal period has been established. The rodent fauna acquired a forest-like character by that time. Northern taiga dark coniferous forests of spruce with a significant admixture of pine developed on the western slope of the Subpolar Urals by the middle of the Subatlantic period, and the content of tundra elements in the stands increased by the end of this period. The microtheriofauna of the studied region had a typical forest appearance characteristic of all Late Holocene taiga communities in northeastern Europe.

The Younger Dryas (12,680–11,590 yr BP) was the last millennial scale cold event of the Quaternary, when a mean annual temperature decline of 3–5 °C impacted severely on the environment. Whereas pollen distributions document changes in land vegetation, details of limnic ecosystem responses to the cooling event and to its recovery are still not well known. Here, we studied the laminated sediments of Lake Steisslingen (SW-Germany) deposited between 13,500 and 11,100 yr BP in order to investigate the evolution of an aquatic ecosystem. Bulk sediment and organic matter composition mark onset and termination of the Younger Dryas, but remain monotonous through this interval, requiring application of organic and isotope geochemical techniques to follow past ecosystem dynamics. The Younger Dryas is characterized by both an abrupt appearance and demise of long-chain alkenones indicative for haptophyte algae. Based on algal and bacterial biomarker distribution, the Younger Dryas can be divided into three stages, each characterized by the dominance of a microorganism group. The first phase was dominated by nC17 alkanes and hopanoids indicative of cyanophytes and heterotrophic bacteria. The second phase shows a proliferation of cold-adapted haptophyte algae, while in the latest phase highly-branched isoprenoids (HBI) reveal an aquatic community shift towards diatoms. Heterocyte glycolipids document a moderate change in N2-fixing cyanobacterial community structure over the Allerod/Younger Dryas transition but show a marked collapse of the cyanobacteria association at the Younger Dryas/Preboreal climate recovery. Terrigenic wax lipids indicate significant changes in vegetation between the Allerod, Younger Dryas and Preboreal chronozones but remain homogeneous within the Younger Dryas.

The main stages of the relationship between forest and steppe communities in the southern part of the Volga Upland have been reconstructed. The existence of primary (preagricultural) steppes of all types has been established. The landscape of this area changed as follows: the steppe landscape changed in the Preboreal and Boreal periods (10 300–7500 BP); the forest-steppe landscape (dominated by forests), in the Atlantic and Early Subboreal periods (7500–3200 BP); forest-steppe (dominated by steppes) and steppe landscapes, from the Late Subboreal period to the present (3200–0 BP); and the first agrocenoses appeared from 2500 BP.

Despite many ideas about the age and processes of sand movements and paleosol formation, there are still some uncertainties in this relations in the Nyírség, eastern Hungary. The major aim of the present study was to clarify the chronology of fossil soils and blown-sand layers in the sand dunes of the Nyírség using radiocarbon (14C) dating on soil and charcoal samples. Charcoal and soil samples were collected from buried paleosols from different sand quarries for 14C dating. The bulk organic carbon content of the buried soil and charcoal pieces recovered from buried fossil soil layers allowed parallel 14C accelerator mass spectrometry dating in several cases. The new 14C results indicate paleosol development during Younger Dryas, while the preceding interstadial was assumed as a cold and dry period when only sand movement occurred in the area. Our results also confirm and support the previous assumptions, that in the Late Glacial, the first paleosol development period was during the Bølling-Allerød Interstadial. Four soil-forming periods could be determined during the Holocene (Preboreal, Boreal, Atlantic, Subatlantic). We have also indirectly identified sand movements during the Oldest Dryas, Younger Dryas, Preboreal, Boreal, and Subatlantic phase in the study area.

This paper presents the first result of a study of two long-term natural archives in the southwestern part of the Western Siberian Plain. Bchron age models based on 17 AMS dates allowed us to determine a chronology of changes in properties of lake and peat deposits. Significant changes in the Holocene were identified according to geochemical indices, accumulation rates, and compositions of the plant macrofossils of sediment cores in Lake Kyrtyma and Oshukovskoe peat bog. Sediments with a low content of organic matter and maximum weathering accumulated in the Late Glacial, below the border of the Holocene. The transition to the Holocene manifested as a black organic gyttja with ostracods and marked warming ∼12–11.2 ka BP. At about 11.2–10.1 ka BP it was replaced by the Preboreal oscillation. Subsequent changes in lake sedimentation were associated with general warming and an unstable hydrological regime. An increase in humidification ∼8.2 ka BP was reflected by lake level rise and contributed to swamping of the watersheds. The aridest Holocene phase at ∼7.1–5.5 ka BP was reliably recorded by geochemical data, but poorly reflected in the stratigraphy of both profiles. Subsequent cooling and the resulting decrease in evaporation began at ∼5.5–4.9 ka BP. A pronounced cardinal shift in sedimentation conditions due to a gradual increase in precipitation was recorded at ∼4.9–2.8 ka BP, though short-term fluctuations towards dryness were also marked at ∼3.5–3.3 ka BP. The most significant increase in humidification and cooling began at 2.8 ka BP. Geochemical indices in the lacustrine sediments are climate sensitive and allowing us to obtain enough reliable data associated with changes in sedimentation environments. The stratigraphy of peat reflected the nuances of climatic changes less clearly and primarily demonstrated the stages of bog self-development; however, sphagnum peat provided a better-resolution record.

Undisturbed sediments are an important source for the reconstruction of the Holocene development of valleys. Wide floodplains with relatively small rivers in a region settled since 5500 BCE offer opportunities for investigations regarding climatic and anthropogenic landscape change. In the context of a motorway construction, excavations were carried out by the Saxonian Heritage Office in the year 2015. At one of the sites it was possible to get a view of the sediments of the Pleiße valley less than 100 m distance from large cross sections described by Neumeister (1964) in a former open cast mine. Archaeological finds and features, plant remains and radiocarbon dating as well as micromorphological and geochemical investigations helped to decipher the age and the characteristics of the Holocene sediments: above Weichselian loamy sands a sedge peat developed in small depressions during the Preboreal and Boreal. The sands and the sedge peat are covered by a “black clay”, which was still the topsoil during the Atlantic period. The sedimentation of 2.3 m thick overbank fines began after 4000 BCE. A depth of 1 m below the surface a medieval Slavic find layer was excavated. These results show that sedimentation processes in the lower Pleiße valley significantly changed after 4000 BCE. It is obvious that the increase in silty material in the floodplain is caused by the land clearance in the Neolithic period. More than half of the silty overbank fines were deposited before the Middle Ages began.

The Barents Sea offers a suitable location for documenting advection of warm and saline Atlantic Water (AW) into the Arctic and its impact on deglaciation and postglacial conditions. We investigate the timing, succession, and mechanisms of the transition from proximal glaciomarine to marine environment in the northwestern Barents Sea. Two studied sediment cores demonstrate diachronous retreat of the grounded ice sheet from the Kvitøya Trough (core S2528) to Erik Eriksen Trough (core S2519). Oxygen isotope records from core S2528 depict a two-step pattern, with lower δ18O values prior to the Younger Dryas (YD), and higher values afterward because of advection of the more saline,18O-enriched AW. At this location, subsurface AW penetration increased during the Allerød and YD/Preboreal transition. In the study area, foraminiferal and dinocyst data from the YD interval suggest cold conditions, extensive sea-ice cover, and brine formation, along with the flow of chilled AW at subsurface and the development of a high-productivity polynya in the Erik Eriksen Trough. Dense winter sea-ice cover with seasonal productivity persisted in the Kvitøya Trough area during the early Holocene, whereas surface warming seems to have occurred during the middle Holocene interval.

Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 and C29) and a hemicellulose-derived sugar biomarker (arabinose), respectively. Both δ2Hn-alkane and δ18Osugar are suggested to reflect mainly leaf water of vegetation growing in the catchment of the Gemündener Maar. Leaf water reflects δ2H and δ18O of precipitation (primarily temperature-dependent) modified by evapotranspirative enrichment of leaf water due to transpiration. Based on the notion that the evapotranspirative enrichment depends primarily on relative humidity (RH), we apply a previously introduced “coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach” to reconstruct the deuterium excess of leaf water and in turn Late Glacial–Early Holocene RH changes from our Gemündener Maar record. Our results do not provide evidence for overall markedly dry climatic conditions having prevailed during the Younger Dryas. Rather, a two-phasing of the Younger Dryas is supported, with moderate wet conditions at the Allerød level during the first half and drier conditions during the second half of the Younger Dryas. Moreover, our results suggest that the amplitude of RH changes during the Early Holocene was more pronounced than during the Younger Dryas. This included the occurrence of a “Preboreal Humid Phase”. One possible explanation for this unexpected finding could be that solar activity is a hitherto underestimated driver of central European RH changes in the past.

Summary We explored how the Younger Dryas (YD)/Holocene transition impacted tropical sea surface temperature (SST) by evaluating marine sedimentary archives at scales unattainable for conventional molecular stratigraphy. In sediments from the Cariaco Basin, we analysed the well-established UK’37 SST proxy via mass spectrometry imaging, and obtained 2D-images of sedimentary proxy distribution at 100 µm resolution and corresponding downcore SST profiles with subannual resolution. SST in the Cariaco Basin remains relatively constant over the YD/Holocene transition, suggesting a decoupling from the major environmental change associated to this event, i.e. the northward shift of the intertropical convergence zone. However, we were able to reveal a short-lived ∼50 year episode of abrupt warming during which average SST increased about 1°C. This episode is synchronous with the Preboreal Oscillation cooling, that led to drier, colder conditions in Europe and North America. The comparison of proxy values, elemental composition and sediment colour from every µm-sized spot further provides clues on SST seasonality and its modulation across the YD/Holocene transition.

Palaeoecology, through the analysis of the interactions between environmental factors and ecosystems, refines the knowledge of the structuring process of plant communities and helps to understand the complexity of past environments. However, it is necessary to analyse the taphonomic phenomena (deposition, conservation, degradation) affecting plant macrofossil assemblages in order to perform relevant palaeoecological analyses. Indeed, plant macrofossils may be under or over-represented in carpological assemblages, depending on the resistance of their cell membranes and the sedimentary condition deposits. For this reason, it is necessary to estimate the representative quality of the conserved part as a source of information. Like all archaeological documents, the plant archives are distorted by the processes of formation of the sedimentary levels and, ignore the diagenetic history of the sedimentary layers could lead to wrong palaeoecological interpretations. To this aim, we analysed plant macrofossils contained in the wet sediments of a Meuse palaeochannel (Autrecourt-et-Pourron, Ardennes, France). This archaeobotanical study of an oxbow lake dated to the Preboreal (11.7–10.7 ka cal. BP), provides a reference of a taphonomic referential according to a hierarchy of organic remain preservations. This framework successfully helped the palaeoecological interpretations of the Autrecourt-et-Pourron off-site, and it has brought robustness to environmental history reconstruction of the early Holocene in the Ardennes Meuse.

Several climate oscillations have been reported from the early Holocene superepoch, the best known of which is the Preboreal oscillation (PBO). It is still unclear how the PBO and the number of climate oscillations observed in Greenland ice cores and European terrestrial records are related to one another. This is mainly due to uncertainties in the chronologies of the records. Here, we present new, high-resolution 10Be concentration data from the varved Meerfelder Maar sediment record in Germany, spanning the period 11 310–11 000 years BP. These new data allow us to synchronize this well-studied record, as well as Greenland ice core records, with the IntCal13 timescale via radionuclide wiggle matching. In doing so, we show that the climate oscillations identified in Greenland and Europe between 11 450 and 11 000 years BP were not synchronous but terminated and began, respectively, with the onset of a grand solar minimum. A similar spatial anomaly pattern is found in a number of modeling studies on solar forcing of climate in the North Atlantic region. We further postulate that freshwater delivery to the North Atlantic would have had the potential to amplify solar forcing through a slowdown of the Atlantic meridional overturning circulation (AMOC) reinforcing surface air temperature anomalies in the region.

This paper presents a comprehensive palaeoenvironmental data set from a trough between glacial curvilineations (an intra-GCL trough) of the Dobrzyn Lake District, north-central Poland. A sediment core taken from the depression was investigated to reconstruct Late Glacial and Holocene environmental changes in north-central Poland using a combination of palynological, macrofossil, sedimentological and geochemical studies. Four main development phases of the studied intra-GCL trough were distinguished. Accumulation of the analysed sediments occurred from the Late Vistulian (Glacial Phase) through the Late Glacial to present times. Our data suggest the persistence of dead ice in the basin up to the Older Dryas (Lacustrine Phase). The sedimentary record of the depression reflects a considerable difference between the Late Glacial/early Holocene and the middle/late Holocene in terms of environmental conditions. The Late Glacial was characterised by rapid environmental changes, while climatic conditions throughout the Holocene were relatively stable, except for the Subboreal period. A small lake was strictly dependent on climatically controlled vegetation changes and erosion tendencies in the vicinity of the Zbojenko site. The lake finally disappeared at the turn of the Younger Dryas and the Preboreal Period. The Preboreal, Boreal and Atlantic Periods encompassed the Early Paludical Phase, during which the water level used to rise and hence the mire could be flooded. The area was covered with dense vegetation and the rate of denudation processes around the site was moderate. The Late Paludical Phase included the Subboreal and most of the Subatlantic. Deciduous forests (with Quercus, Carpinus, Corylus) dominated around the site. Major changes occurred between the late Subboreal and the early Subatlanic as a result of the growing human impact on the environment. The Subatlantic ends with the human impact phase (Middle Age), dominated by human impact, little accumulation of sediments and highly increased denudation.

Palaeoecological studies in coversand areas are sparse as organic remains generally do not preserve well in sandy deposits. An AMS-dated Holocene peat sequence in a palaeochannel in a natural depression (the Liereman), flanked by coversand ridges proved to be an exceptional and valuable archive of long-term vegetation dynamics in the Campine (N Belgium). Analyses of microfossils, such as pollen, spores and non-pollen palynomorphs, as well as macrofossils of plants and other organisms have given insight in the vegetation dynamics over the past 11,500 years. Grasslands developed during the Rammelbeek phase of the Preboreal at the expense of the birch woodlands that characterized the Friesland phase of the Preboreal. During the Preboreal the depression was ecologically diverse with abundant resources for human subsistence, such as permanent fresh water, game and edible plants. However, to date no contemporaneous archaeological sites are known in the area. In the woodlands on the coversand ridges pines became the dominant regional vegetation towards the Boreal. The resulting lowering of ground water levels led to a decrease of the water availability and associated resources for hunter-gatherer societies. Yet, (early) Mesolithic hunter-gatherers settled in the area, however only temporarily. During the Atlantic coniferous forests were succeeded by mixed deciduous woodlands, while the freshwater availability decreased further. This possibly explains the near absence of middle and late Mesolithic sites in the Liereman area. From the Subboreal onward deciduous woodlands opened, probably as a result of human activity. Finally, through deforestation the area in and around the Liereman depression was partly cleared for agricultural purposes during the Subatlantic.

International audience; The Early Holocene (12-8.2 cal ka) deglaciation and pulsed warming was associated in Iceland with two major generations of jökulhlaups around the Vatna ice-cap (Vatnajökull), at ca 11.4-11.2 cal ka and ca 10.4-9.9 cal ka, and major tephra emissions from the Grímsvötn and Bárðarbunga subglacial volcanoes. The earliest flood events were recorded inland during the Middle Younger Dryas and their deposits were overlain by the Early Preboreal Vedde Ash (11.8 cal ka). The first Holocene flood events (ca 11.4-11.2 cal ka) are issued from a glacial advance. The second, and major, set of floods was partly driven by the Erdalen cold events and advances (10.1-9.7 10Be ka) initially issued from the Bárðarbunga (10.4, 10.1-9.9 ka) and Grímsvötn volcanoes (Saksunarvatn tephra complex, ca. 10.2-9.9 cal ka). These floods were also fed by the residual glacio-isostatic depressions below the Vatnajökull that enabled the storage of meltwaters in large subglacial lakes or aquifers until ca. 9.3 cal ka. This storage was enhanced by icedamming and permafrost, especially during the twinned Erdalen events. Due to the glacio-isostatic rebound, the general slope was nearly flat, and the valley was partly filled with sediments until ca 10.8 cal ka. Temporary lacustrine deposits in this valley resulted from the very broad splay of waters as for the ca 11.2 cal ka and ca 10.1-9.9 cal ka flood, due to regional permafrost. These floods had a potential duration of several months as they were mostly fed by climate-driven meltwater. The maximal volume evacuated by these events did not greatly exceed 1 × 106 m3 s−1 from the flood-affected transverse profile of the valleys that remain partly filled with sediments.

This chapter explores site-type variability in the course of the Early Mesolithic at the coast of central Norway. The Early Mesolithic was a period of great alterations in climate, landscape and oceanic environment. The Arctic conditions that prevailed on the coast when hunter-gatherers first arrived c. 9500, gradually gave way to a warmer climate. A cold pulse, known as the Preboreal oscillation (PBO), hit Scandinavia and Europe c. 9300–9200 cal bc, before the temperatures rose again. Midway through the Early Mesolithic period, c. 8800 cal bc, the ice melted away from all the large fjords and coastal waters, pushing the cold-tolerant fauna northwards. The parallel establishment of the Norwegian Atlantic Current provided stable and liveable conditions to a new range of marine species. For the coastal hunter-gatherers, these fluctuations must have greatly affected the resource base. Previous studies have pointed out that generalized toolkits and flexible mobility systems seem to have been ways of coping with the changing conditions. Was also site type an active variable of their adaptive strategy within this period? On the basis of Binford’s forager–collector continuum (1980), 18 sites are analyzed in terms of artefacts, tools, size, layout and features to see if there are diachronic trends in the frequency of different site types that can be related to the palaeoenvironmental trajectory of the period. The study points to a development from short visits when hunting activities and gearing up were the focus in the earliest part of the Early Mesolithic, to a more stable site pattern where residential bases were established near predictable food resources. This happens parallel with the environmental and climatic fluctuations, and it is likely that these trajectories are related.

In this study, we focus on the environmental changes recorded in the San River valley (Stubno–Naklo site, south-eastern Poland) at the beginning of the Holocene. This multi-proxy study for the first time in the region of the northern foreland of the Western Carpathians included quantitative thermal reconstruction based on Chironomidae and high-stratigraphic resolution of 14C AMS dating. We hypothesised that (i) climate events during the Early Holocene contributed to ecosystem turnovers via stimulating disturbances related to the river's fluvial activity and (ii) woodland and oxbow lake ecosystems became more resilient to flood disturbances along with the advance of forest succession on the floodplain. The results revealed that the response of ecosystems on the Early Holocene warming was strongly linked with the decrease in fluvial activity of the river. The reconstruction of the mean July temperature based on Chironomidae revealed the exceptionally high rate of warming during the period of ca. 11,490–11,460 cal. BP (at least 1 °C per decade) up to values > 2 °C than modern ones. During this period, the lake trophy and productivity started to increase with a simultaneous spread of Betula woodlands on the alluvial plain. The “Preboreal oscillation” cooling was dated at ca. 11,450–11,250 cal. BP. At that time, an increased climate instability led to a higher rate of extremal events such as flood at ca. 11,400–11,330 cal. BP, which probably led to the disruption of the Betula population. The development of riparian woodlands, initiated by the expansion of Ulmus from ca. 11,100 cal. BP, and further spread of Quercus and Fraxinus excelsior on the alluvial plain and lower river terraces increased plant transpiration and therefore limited the river runoff and its fluvial activity. This, together with the expansion of reed belt communities, probably limited the impact of floods on the oxbow lake. However, ca. 10,010–9880 cal. BP traces of higher fluvial activity, but of lower impact, were recorded.