Pollen stratigraphy of the Late Pleistocene sediments at Mommark, Als, South Denmark

Past environmental changes in the Baltic area are discussed on the basis of pollen and spores recovered from marine sediments in a series of cliff sections at Mommark, in southern Denmark. The sediment succession represents Jessen & Milthers' (1928) Eemian pollen zones c-h, or Andersen's (1961 1975) zones E1/2-E7, as well as the earliest Weichselian pollen zone i, or EW-1, the Herning Stadial. A correlation with annually laminated German sequences (e.g. Bispingen) indicates that the sequence spans approximately 11 000 years. Marine deposition began c. 300 years after the beginning of the Eemian Interglacial Stage and continued to shortly before the end of pollen zone E7, at c. 10 600 years after the beginning of the Eemian. Sedimentation rates varied through the time period represented by the sequence, with initial deposition relatively rapid at c. 0.35 cm yr^-1 for the first c. 300 years. Rates then decreased to 0.029 cm yr^-1 for the next 2700 years and remained low, though varying, throughout the rest of the sequence. Overall, the rates indicate that sediment supply was highly restricted throughout the interglacial, possibly reflecting the dense forest vegetation that colonized the hinterland.     

Palaeoenvironments of a complete Eemian sequence at Mommark, South Denmark: foraminifera, ostracods and stable isotopes

A new investigation of the coastal cliff section at Mommark in southern Denmark has revealed a complete Eemian interglacial sequence for the first time in the southwestern Baltic area. Environmental changes through the lacustrine and marine interglacial deposits are discussed on the basis of foraminiferal assemblages and stable isotope composition as well as ostracods. In general, the assemblages indicate relatively high temperatures throughout the Eemian, and the Lusitanian foraminiferal species Pseudoeponides falsobeccarii Rouvillois has been reported for the first time from the Eemian of northwest Europe. A floating chronology of the deposits is based on a previously published correlation of the local pollen stratigraphy with annually laminated sequences in northern Germany. An initial early Eemian lacustrine phase, with ostracodal indication of deposition in a large freshwater lake, lasted until c. 300 years after the beginning of the interglacial, i.e. to the transition between the regional pollen zones E2 and E3. After that, marine conditions persisted almost throughout the interglacial, and the Cyprina Clay was deposited. The foraminiferal and ostracodal assemblages indicate that relatively deep water prevailed in the area until c. 6000 years after the beginning of the interglacial. However, both the foraminiferal assemblages and the oxygen isotope results show that a trend from relatively high salinity to lower salinity conditions had begun already at about 4000 years. After c. 6000 years the fauna indicates a gradual change to shallower water and further reduction in salinity, the latter also being reflected by a general decrease in the oxygen isotope values. The marine deposition ended at c. 10 600 years after the beginning of the Eemian, i.e. within the topmost part of pollen zone E7. This was succeeded by a late Eemian and early Weichselian freshwater phase.     

Diatom succession of a dislocated Eemian sediment sequence at Mommark, South Denmark

The Mommark sequence represents a nearly complete record of sedimentation in the Eemian (MIS 5e), and the diatom succession covers almost the entire interglacial. A floating chronology of the deposits is based on correlation of the local pollen stratigraphy with annually laminated sequences in northern Germany. The diatom succession starts with a short freshwater stage followed by a similarly episodic transitional brackish phase, which began c. 300 years after the beginning of the Eemian interglacial. A few hundred years later, simultaneously with the start of deposition of the shallow marine sediment, Cyprina Clay, the flora turns almost fully marine, suggesting salinities clearly higher than at present. The culmination of the marine transgression occurs close to the climatic optimum of the Eemian interglacial, c. 3000 years after the beginning of the interglacial. In the several metres thick Cyprina Clay, only marginal changes in the composition of diatom taxa are noticed. According to the diatom stratigraphy and chronostratigraphy based on regional pollen zones, the total duration of the Eemian Sea phase with brackish/marine conditions was c. 10 500 years. As the sedimentation of the Cyprina Clay ends, the proportions of diatom species thriving in freshwater increase, but the marine taxa remain common. The mixture of species with non-compatible ecological requirements suggests allochthonous input from freshwater and/or tidal estuary environment. The results of this study are consistent with studies of other aquatic fossil assemblage data from this site.     

Biostratigraphy of Eemian sediments at Mertuanoja, Pohjanmaa (Ostrobothnia), western Finland

The till-covered clay and silt deposits at Mertuanoja, Pohjanmaa (Ostrobothnia), western Finland, have been investigated in great detail. The Eemian interglacial environment is reconstructed here on the basis of pollen, diatom and dinoflagellate analyses. The pollen stratigraphy shows an interglacial vegetational succession reflecting stable climatic conditions typical of the Eemian Stage in the Pohjanmaa area. The initial Betula forests were followed by Pinus-Betula forests with Quercus. The next successional phase was dominated by Betula, Pinus and Alnus; temperate deciduous trees and Corylus also grew in the area. Later, Picea advanced and temperate deciduous trees declined. Some Corylus was, however, still present and thermophilous Osmunda thrived in wet places. The diatom record indicates that the sediments were deposited first in a freshwater basin, then in the Eemian Baltic Sea, and finally in a freshwater basin once more. The presence of dinoflagellates demonstrates that the Eemian Baltic Sea, when at its maximum extent, was connected to the Atlantic Ocean, which brought northern cool-temperate surface waters to Finland as far north as Mertuanoja. Mertuanoja is the first interglacial site at which numerous dinoflagellate cysts were encountered in Finnish Quaternary sediments.     

Early Last Interglacial palaeoenvironments in the western Baltic Sea: benthic foraminiferal stable isotopes and diatom‐based sea‐surface salinity

Knudsen, K. L., Jiang, H., Kristensen, P., Gibbard, P. L. & Haila, H. 2011: Early Last Interglacial palaeoenvironments in the western Baltic Sea: benthic foraminiferal stable isotopes and diatom‐based sea‐surface salinity. Boreas, 10.1111/j.1502‐3885.2011.00206.x. ISSN 0300‐9483. Stable isotopes from benthic foraminifera, combined with diatom assemblage analysis and diatom‐based sea‐surface salinity reconstructions, are used for the interpretation of changes in bottom‐ and surface‐water conditions through the early Eemian at Ristinge Klint in the western Baltic Sea. Correlation of the sediments with the Eemian Stage is based on a previously published pollen analysis that indicates that they represent pollen zones E2–E5 and span ～3400 years. An initial brackish‐water phase, initiated c. 300 years after the beginning of the interglacial, is characterized by a rapid increase in sea‐surface and sea‐bottom salinity, followed by a major increase at c. 650 years, which is related to the opening of the Danish Straits to the western Baltic. The diatoms allow estimation of the maximum sea‐surface salinity in the time interval of c. 650–1250 years. After that, slightly reduced salinity is estimated for the interval of c. 1250–2600 years (with minimum values at c. 1600–2200 years). This may be related to a period of high precipitation/humidity and thus increased freshwater run‐off from land. Together with a continuous increase in the water depth, this may have contributed to the gradual development of a stratified water column after c. 1600 years. The stratification was, however, particularly pronounced between c. 2600 and 3400 years, a period with particularly high sea‐surface temperature, as well as bottom‐water salinity, and thus a maximum influence of Atlantic water masses. The freshwater run‐off from land may have been reduced as a result of particularly high summer temperatures during the climatic optimum.     

Late Saalian and Eemian palaeoenvironmental history of the Bol''shoy Lyakhovsky Island (Laptev Sea region, Arctic Siberia)

Palaeoenvironmental records from permafrost sequences complemented by infrared stimulated luminescence (IRSL) and [Formula: See Text]Th/U dates from Bol'shoy Lyakhovsky Island (73°20'N, 141°30'E) document the environmental history in the region for at least the past 200 ka. Pollen spectra and insect fauna indicate that relatively wet grass-sedge tundra habitats dominated during an interstadial c. 200-170 ka BP. Summers were rather warm and wet, while stable isotopes reflect severe winter conditions. The pollen spectra reflect sparser grass-sedge vegetation during a Taz (Late Saalian) stage, c. 170-130 ka BP, with environmental conditions much more severe compared with the previous interstadial. Open Poaceae and Artemisia plant associations dominated vegetation at the beginning of the Kazantsevo (Eemian) c. 130 ka BP. Some shrubs (Alnus fruticosa, Salix, Betula nana) grew in more protected and wetter places as well. The climate was relatively warm during this time, resulting in the melting of Saalian ice wedges. Later, during the interglacial optimum, shrub tundra with Alnus fruticosa and Betula nana s.l. dominated vegetation. Climate was relatively wet and warm. Quantitative pollen-based climate reconstruction suggests that mean July temperatures were 4-5°C higher than the present during the optimum of the Eemian, while late Eemian records indicate significant climate deterioration.     

A sedimentary record from a deep Quaternary valley in the southern Lillebælt area, Denmark: Eemian and Early Weichselian lithology and chronology at Mommark

A unique sequence of Late Saalian, Eemian and Early Weichselian strata is exposed in a coastal outcrop at Mommark in the western Baltic. The sedimentary facies and faunas reflect palaeoenvironmental changes from an initial freshwater lake followed by marine transgression and interglacial deposition in a palaeo-Baltic sea. The upper part of the Eemian marine record indicates regression followed by lacustrine sedimentation and deposition of Early Weichselian aeolian sediments, which are truncated by an erosional unconformity overlain by a till bed. The lower and middle parts of the sequence have previously been correlated with the European glacial-interglacial stratigraphy on the basis of pollen analysis, while the upper part has been dated for the present study using optically stimulated luminescence (OSL) of samples from the aeolian and glacial deposits. A similar complete glacial-interglacial-glacial succession has not previously been recorded from this area. The Mommark sequence of conformable strata has been subjected to lateral compression, evidenced by folding and low-angle reverse faults. Seismic records from the adjacent waters in the western Baltic reveal a system of buried Quaternary valleys in the area. It is suggested that the interglacial deposition took place in a basin within one of these valleys and that a slab constituting the Mommark sequence, originating from the margin of a valley, has been glaciotectonically displaced northwestwards to the present location.     

A multi‐proxy palaeoenvironmental and geochronological reconstruction of the Saalian‐Eemian‐Weichselian succession at Klein Klütz Höved,NE Germany

Here we present a multi‐proxy investigation of the Klein Klütz Höved (KKH) coastal cliff section in northeastern Germany, involving lithofacies analysis, micromorphology, micropalaeontology, palynology and luminescence dating of quartz and feldspar. We subdivide the local stratigraphy into three depositional phases. (i) Following a Saalian advance (MIS 6) of the Scandinavian Ice Sheet, the penultimate deglaciation (Termination II) at the site occurred between c. 139 and 134 ka, leading to the establishment of a braided river system and lacustrine basins under arctic‐subarctic climate conditions. (ii) In the initial phase of the Eemian interglacial lacustrine deposits were formed, containing warm‐water ostracods and a pollen spectrum indicating gradual expansion of woodlands eventually containing thermophile deciduous forest elements. A correlation of the local pollen assemblages with Eemian reference records from central Europe suggests that fewer than 750 years of the last interglacial period are preserved at KKH. The occurrence of brackish ostracods dates the onset of the Eemian marine transgression at the section at c. 300–750 years after the beginning of the last interglacial period. (iii) Directly above the Eemian record a ~10‐m‐thick sedimentary succession of MIS 2 age was deposited, implying a significant hiatus of c. 90 ka encompassing the time from middle and upper MIS 5e to late MIS 3. During the Late Weichselian, KKH featured a depositional shift from (glacio‐)lacustrine to subglacial to recessional terminoglacial facies, with the first documented Weichselian ice advance post‐dating 20±2 ka. Overall, the KKH section represents an exceptional sedimentary archive for palaeoenvironmental reconstructions, covering the period from the Saalian glaciation and subsequent Termination II to the early Eemian and Late Weichselian. The results refine the existing palaeogeographical and geochronological models of the late Quaternary history in the southwestern Baltic Sea area and allow correlations with other reference records in a wider area.     

A continuous Eemian-Early Weichselian sequence containing pollen and marine fossils at Fjøsanger, western Norway

A complete interglacial cycle, named the Fjøsangerian and correlated with the Eemian by means of its pollen stratigraphy, is found in marine sediments just above the present day sea level outside Bergen, western Norway. At the base of the section there are two basal tills of assumed Saalian ( sensu lato ) age in which the mineralogy and geochemistry indicate local provenance. Above occur beds of marine silt, sand and gravel, deposited at water depths of between 10 and 50 m. The terrestrial pollen and the marine foraminifera and molluscs indicate a cold-warm-cold sequence with parallel development of the atmospheric and sea surface temperatures. In both environments the flora/fauna indicate an interglacial climatic optimum at least as warm as that during the Holocene. The high relative sea level during the Eemian (at least 30 m above sea level) requires younger neotectonic uplift. The uppermost marine beds are partly glaciomarine silts, as indicated by their mineralogy, drop stones and fauna, and partly interstadial gravels. The pollen indicates an open vegetation throughout these upper beds, and the correlation of the described interstadial with Early Weichselian interstadials elsewhere is essentially unknown. The section is capped by an Early Weichselian basal till containing redeposited fossils, sediments, and weathering products. Several clastic dikes injected from the glacier sole penetrate the till and the interglacial sediments. Radiocarbon dates on wood and shells gave infinite ages. Amino acid epimerization ratios in molluscs support the inferred Eemian age of the deposit. The Fjøsangerian is correlated with the Eemian and deep sea oxygen isotope stage 5e; other possible correlations are also discussed.     

A tephra-based correlation between the Faroe Islands and the Norwegian Sea raises questions about chronological relationships during the last interglacial

Marine ash zones from the last interglacial period have been described from cores from the North Atlantic and an ash zone from the middle part of the interglacial has been observed in connection with a major cooling event. Here we present evidence for a coeval ash zone in a terrestrial site on the Faroe Islands. The investigated sediments are correlated with the upper part of oxygen isotope stage 5e and the beginning of stage 5d. The Eemian climatic optimum is represented in the lower part of the sequence close to the first occurrence of the ash zone. A tephra-based correlation suggests that the climatic optimum was synchronous with the marine record from the Norwegian Sea, but several thousand years later than in Eemian sections of west central Europe. However, many questions on the chronological relationship between the Eemian and oxygen isotope stage 5e still remain to be answered.     

A Late Pleistocene sequence at Margreteberg, southwestern Sweden

At Margreteberg, southwestern Sweden, a comple Pleistocene sequence has been stratigraphically investigated. Strata of clay, silt, sand, peat and solifluction layers are overlain by till-like sediments which are covered by sandy-clayey strata. By means of biostratigraphical analyses (foraminifera, olluscs, wood remains, pollen and diatoms), a reconstruction of the palaeoenvirnmental development has been obtained. Radiocarbon measurements and amiono acis ratios have been carried out in order to date the sediments. The foraminifera in the lowermost clay strata indicate Arctic or boreal-Arctic marine environment during the Late Saalian or Late Elsterian perods The δ¹⁸ Ovalues and molluscs also suggest that the clay was deposited in glaciomarine conditions. Amino acid ratios (D/L=0.25) of Hiatella in the clay imply an age between the Holsteinian and Eemian Interglacials. Teh peat layers contain a pollen flora. Prtedominated by Picea and Pinus, and are pollen analytically dated to the end of the Eemian interglacial. The solofluction sediments most probably were fromed during the first stage (s) of the Early weichselian and may include the initaial phase of the Brorup Interstadial (the Rodebaek interstadial). During this stage(s) aretic-Subarctic conditions previaled reflected by a pollen flora with a predominance of herbs and shrubs. Acidophilous and aerohpilous diatoms indicate oligotrophic shallow wate conditions in an Arctic environment, when almost no leaching of mineral solis occurred. The solofluction sediments also contain reworked interglacial (Eemian) pollen and brackish-Marine diatoms. Radiocarbon dating of the peat, wood and solofluction sediments yieded infinnite ages>40,000B.P.     

Last Interglacial marine environments in the White Sea region, northwestern Russia

Marine sediments from river sections in the Mezen River drainage, northwest Russia, have been analysed for dinoflagellate cysts, foraminifers and molluscs. The sediments were dated by pollen analysis and by reference to the local sea-level history, and are Late Saalian to late Eemian (c. 133 to 119.5 kyr in age). The Late Saalian deglaciation was characterized by Arctic conditions, but a few centuries into the Eemian the Gulf Stream system carried warm Atlantic water into the region. At 129.8 kyr BP there was a marked increase in the influx of Atlantic water, and the advection of warm Atlantic water was stronger and probably penetrated further eastwards than at present. The molluscs, dinoflagellate cysts and foraminifers reflect conditions warmer than present and that the optimum temperature occurred at the time of the early Eemian global sea-level rise. Around 128 kyr BP, the eustatic sea-level rise was curbed by isostatic rebound and accompanying regression and constriction of marine passages to the White Sea. Local, low-saline, stratified basins developed and characterized the next five to six millennia.     

Diatom responses to limnological and climatic changes at Ribains Maar (French Massif Central) during the Eemian and Early Würm

High-resolution diatom analysis was carried out to assess the limnological and climatic changes that took place at Ribains maar (French Massif Central) during the Late Pleistocene (∼131–∼105 ka BP), with a focus on the Eemian interglacial in particular. Numerical analyses were used to show that most of the variability in the fossil diatom assemblages was due to climate independently from the changes in the lake catchment vegetation (as represented by pollen data). Diatom-based quantitative reconstructions of the past limnological conditions, as well as a comprehensive literature review on the auto-ecological requirements for the principal diatom taxa, were used to interpret the record. An absolute time-scale for the sequence was derived by matching the major pollen shifts with the radiometrically dated changes in oxygen isotopes observed in Italian stalagmites. This study shows that at Ribains maar, the transition from the Riss (=Saalian) Glacial to the Eemian interglacial was marked by a gradual increase in the contribution of spring-blooming diatom species, indicating a longer growing season and milder winter/spring conditions at that time. A short cooling event interrupts this trend and may correspond to a stadial. At the start of the Eemian a peak in benthic taxa and the suppression of spring-blooming flora probably reflects the effects of deglaciation on the catchment. During the Eemian interglacial itself three main phases were distinguished within the diatom record. The first phase (∼8000 years in duration) was dominated by Stephanodiscus minutulus, which suggests that intense mixing in the water-column took place during spring. The pollen record was simultaneously dominated by Quercus and Corylus that typify this phase as the climatic optimum of the Eemian. The second phase, almost equal in duration to the first phase (∼7000 years), is generally dominated by Cyclotella taxa and suggests a less productive lake and much reduced period of spring mixing compared with the first phase. In the pollen diagram this corresponds to an interval dominated by Carpinus–Picea–Abies that indicates a cooler and wetter climate. The third and last phase of the Eemian, ∼2000 year long, saw the return to Stephanodiscus-dominated assemblages, indicating a warming that may correspond to the Dansgaard–Oeschger event 25 identified in the Greenland ice-core record. In the early stage of the Würm Glacial (=Weichselian), assemblages in the Melisey I stadial (∼3000 year long) were dominated by either Aulacoseira subarctica or Asterionella formosa, which suggest colder spring conditions than during the late Eemian, but not as cold as the ones indicated by the pollen record. Stephanodiscus spp. again dominate during the Saint-Germain Ia interstadial (∼5000 year long) suggesting a return to the conditions that prevailed before the Melisey stadial, in agreement with the pollen record. The record ends with the Montaigu cold event, which is characterised by a Pinus peak in the pollen record, and corresponds to a large abundance of A. subarctica in the diatom sequence. Throughout the Eemian the abundance of Stephanodiscus spp., which is thought to be driven by winter conditions, show cyclic fluctuations that most likely match the cooling events identified in a pollen record from Germany. Variation in insolation throughout the Eemian may have been the driving factor behind the species succession observed in the diatom sequence. While this study demonstrates that diatom analysis of lake sediment can provide very detailed information on long-term climate change, a review of the few other diatom investigations published on European Eemian deposits shows that this technique has been so far seldom used to its full potential in this context in central and southern Europe.     

A Late Saalian, Eemian and Weichselian marine sequence at Nørre Lyngby, Vendsyssel, Denmark

A 120 m thick marine Quaternary sequence resting on Upper Cretaceous chalk at Nørre Lyngby has been stratigraphically analysed on the basis of its foraminiferal content. The foraminiferal zones in the Nørre Lyngby boring are compared with corresponding zones from borings and outcrops in adjacent areas in Vendsyssel and Kattegat, and a general zonation covering the whole area is proposed. The lower part of the marine sequence at Nørre Lyngby represents deposits of pre-Eemian, possibly Saalian, and Eemian age. The Early Weichselian seems to be missing, while most of the Middle and Late Weichselian foraminiferal zones known from Vendsyssel occur. The foraminiferal zones and the corresponding macrofossil zones are correlated with the oxygen isotope stratigraphy. A cross-section through deposits from the Saalian-Eemian-Weichselian marine basin in North Jutland and the Kattegat illustrates the development of the basin through this period of time. The centre of basin subsidence shifted from the southwest in the pre-Eemian to the northeast in the Eemian, and remained there throughout the Weichselian.     

Upper Pleistocene stratigraphy at the Medininkai site, eastern Lithuania: a continuous record of the Eemian-Weichselian sequence

Eemian—Weichselian sequences, located outside the maximum limit of the Late Weichselian ice sheet, provide excellent opportunities for the discovery of continuous sedimentary records encompassing the whole Last Interglacial/Glacial cycle. Such a sequence is recorded in a borehole (117P) through the succession in a small kettlehole lake located at Medininkai, eastern Lithuania. The succession consists of peat, gyttja and silt deposited on top of a Saalian till. Pollen and plant macrofossil analysis, lithological analysis, U/Th dating and mineral magnetic measurements on the sediments have allowed 19 lithostratigraphic units and 16 local pollen assemblage zones (LPAZ) to be identified. The palaeocarpological record reveals a clear transition from the Saalian Glacial to the Weichselian stadial and interstadial phases. The mineral magnetic parameters suggest a good correlation between the concentration of magnetic minerals and stadial and interstadial periods. The Merkine (Eemian) Interglacial and two Early Weichselian Interstadials, Jonionys 1 (Brörup) and Jonionys 2 (Odderade), separated by cryomers, are identified. Intervals interpreted as analogous to the Middle Weichselian Denekamp and Hengelo interstadials are also recognized on the basis of pollen assemblages. The results show alternating periglacial and interstadial palaeoenvironments in Lithuania during the Early and Middle Weichselian and are of importance for Late Pleistocene palaeoenvironmental reconstruction of the Baltic area as a whole.     

Late Pleistocene and Holocene vegetation and climate on the northern Taymyr Peninsula, Arctic Russia

Pollen data from a Levinson-Lessing Lake sediment core (74°28'N, 98°38'E) and Cape Sabler, Taymyr Lake permafrost sequences (74°33'N, 100°32'E) reveal substantial environmental changes on the northern Taymyr Peninsula during the last c. 32 000 [Formula: See Text]C years. The continuous records confirm that a scarce steppe-like vegetation with Poaceae, Artemisia and Cyperaceae dominated c. 32 000-10 300 [Formula: See Text]C yr BP, while tundra-like vegetation with Oxyria, Ranunculaceae and Caryophyllaceae grew in wetter areas. The coldest interval occurred c. 18 000 yr BP. Lateglacial pollen data show several warming events followed by a climate deterioration c. 10 500 [Formula: See Text]C yr BP, which may correspond with the Younger Dryas. The Late Pleistocene/Holocene transition, c. 10 300-10 000 [Formula: See Text]C yr BP, is characterized by a change from the herb-dominated vegetation to shrubby tundra with Betula sect. Nanae and Salix. Alnus fruticosa arrived locally c. 9000-8500 [Formula: See Text]C yr BP and disappeared c. 4000-3500 [Formula: See Text]C yr BP. Communities of Betula sect. Nanae, broadly distributed at c. 10 000-3500 [Formula: See Text]C yr BP, almost disappeared when vegetation became similar to the modern herb tundra after 3500-3000 [Formula: See Text]C yr BP. Quantitative climate reconstructions show Last Glacial Maximum summer temperature about 4°C below the present and Preboreal (c. 10 000 [Formula: See Text]C yr BP) temperature 2-4°C above the present. Maximum summer temperature occurred between 10 000 and 5500 [Formula: See Text]C yr BP; later summers were similar to present or slightly warmer.     

Quantitative reconstruction of climate variability during the Eemian (Merkinė) and Weichselian (Nemunas) in Lithuania

Little is known concerning climate changes in the Eastern Baltic region during the last interglacial–glacial cycle and in particular, climate changes during the Weichselian. In this study, a quantitative reconstruction of the mean January and July temperature for the Medininkai-117 site in Lithuania is presented. The reconstruction is based on pollen and plant macrofossils from this site, which reveal that the vegetation was characteristic of many northern Europe sites during the Eemian and Early Weichselian. Gradual evolution of the vegetation suggests that relatively uniform climate conditions existed during the Eemian. Our reconstructions support the view of a relatively stable Eemian, with short cooling phases of low amplitude. A strong increase in temperature was apparent during the beginning of the interglacial and decrease during the transition to the Weichselian. Reconstructed July temperatures of the Eemian interglacial were approximately 2 °C higher than today (18.5 °C; today: 16.2 °C) and were similar to today for January (− 5.2 °C; today: − 5.1 °C). July temperatures during the Early Weichselian were only ~ 2°C lower than during the Eemian, whereas the January temperatures gradually decreased. Winter temperatures were relatively high (above − 10 °C) during the Early Weichselian.     

Palaeoenvironment of the Karelian Isthmus, the easternmost part of the Gulf of Finland, during the Litorina Sea stage of the Baltic Sea history

The palaeoenvironment of the Karelian Isthmus area during the Litorina Sea stage of the Baltic Sea history, between 8.0 and 4.5 kyr BP (8.8-5.2 cal. kyr BP), was reconstructed by studying four sites located on the Karelian Isthmus in Russia. Methods included diatom and pollen analyses, sediment lithostratigraphical interpretation and ¹⁴C dating. The brackish-water (Litorina) transgression began c. 7.7 kyr BP (8.45 cal. kyr BP) in the Karelian Isthmus area. The transgression maximum occurred between 6.7 and 5.7 kyr BP (7.6-6.5 cal. kyr BP), depending on the glacio-isostatic land uplift rate. Regarding the vegetation, the maximum occurrence of temperate deciduous trees took place at the same time. The transgression was interrupted by a short-lived sea-level standstill during the middle phase of the main transgression, c. 6.3 kyr BP (7.2 cal. kyr BP), on the eastern part of the isthmus. The highest Litorina shoreline is located between 8 and 13 m above present sea-level and the amplitude of the Litorina transgression has varied between 5 and 7 m. The 8.2-kyr cold event is not evident, but the sea-level standstill around 6.3 kyr BP (7.2 cal. kyr BP) could reflect a cool episode at that time in the Karelian Isthmus area.     

A Late Pleistocene marine clay succession at Kriegers Flak,westernmost Baltic,southern Scandinavia

In the Baltic Sea south of Skåne county in southern Sweden, an over- consolidated marine clay succession on the northeastern slope of Kriegers Flak was observed in shallow seismic data as a unit overlain by younger Weichselian sediments. Two cores were taken from the clay succession. The Foraminifera present were predominantly of two species, Elphidium excavatum and Elphidium albiumbilicatum, reflecting deposition under arctic– boreal conditions. Stable oxygen isotope analyses were performed on foraminiferal tests, and the results show extremely light δ¹⁸O values ranging between −11‰ and −12‰. The cause of these extreme values is uncertain but may result from the high influence of meltwater. Brackish conditions are also indicated by the tolerance for low salinity shown by the Foraminifera. Radiocarbon dating shows an infinite age >40000 yr BP. The pollen flora seems mainly to have been redeposited, which makes interpretation difficult. The sea may have entered the Baltic basin during periods with high eustatic levels, an isostatic downloading of the crust, or a combination of both. It is suggested that the deposition of the overconsolidated marine clay succession occurred in the Late Saalian, Early Eemian or Early Weichselian. © 1998 John Wiley & Sons, Ltd.     

Tepsankumpu revisited — pollen evidence of stable Eemian climates in Finnish Lapland

Several till-covered organic deposits, principally lake gyttja, in Finnish Lapland have been correlated with the last (i.e. Eemian) interglacial on the basis of their lithostratigraphic position and pollen stratigraphy. Most of the sequences are short, but together with three longer sequences from Finnish Lapland and one from Swedish Lapland (Leveäniemi) they provide a complete picture of Eemian vegetational and climatic development. The Tepsankumpu site was revisited, and the till-covered thick freshwater gyttja deposit was studied in detail for pollen in order to search for signals of rapid climatic fluctuations postulated for the earlier part of the Eemian on the basis of Greenland ice core studies. The Eemian pollen stratigraphy in Finnish Lapland closely resembles the Holocene pollen stratigraphy of the area. The abundance of spruce and alder pollen suggests, however, more northerly limits for forest vegetation zones during the Eemian than during the Holocene. Oak also grew closer to Lapland, indicating a wanner climate than during the Holocene climatic optimum. The Tepsankumpu pollen stratigraphy indicates climatic stability over the entire time-span it covers, i.e. the major part of the interglacial. This finding is in conflict with results from Greenland GRIP ice core studies and interpretations of some Continental European Eemian pollen diagrams.