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The coastal cliffs in Klaksvik (Borðoyar Bay) are the only known locality with Eemian sediments in the Faroe Islands. Previous studies carried out there focused on the sedimentology, tephra chemistry, paleoecology including aquatic environment, or the age of the deposits. In the lacustrine, clayey to silty gyttja we collected scattered wood fragments, identified as Larix sp., Pinus sp., Taxus sp. and Betulaceae? In addition, these wood remains contain numerous trace fossils, made by marine wood-boring bivalves (Teredolites longissimus), which together with a discussion about the areal extent of the identified tree species leads us to conclude that they are non-native, i.e. driftwood. Northern Siberia is usually regarded as the most likely source area for driftwood in the eastern North Atlantic region. We combined the approximate transport distance from the areal extent of the wood with the main directions of marine currents in the relevant section of the North Atlantic. Adding the known average marine current velocities during the penultimate interglacial resulted in 130–200 days for transport from North America and 350–1100 days from Siberia. Comparing this with the maximal buoyancy period for the identified tree species, we conclude that the Faroese driftwood may originate not only from Siberia, but also from the eastern coast of North America, especially from the region around the Great Lakes, as well as from western Europe. (Less)

A unique geological process of extrusion of lagoon marl from beneath massive migrating sand dunes is characteristic for large segments of the Curonian Spit – a ~100-km-long sandy barrier that separates the Curonian Lagoon from the Baltic Sea. Exposures of a composite set of Holocene organic sediments such as gyttja, clayey gyttja and gyttja clay, collectively referred to as ‘lagoon marl’, are common along the northern half of the lagoon coast of the spit. The marl outcrops rise up to 3–4 m above the lagoon level and owe their origin to extrusion from their 7–8 m in situ depth beneath the present regional water table. New detailed investigations of the Baltic Sea bottom along the southern half of the Curonian Spit using side-scan sonar, a multibeam echosounder, seismic imaging, sediment sampling and video observations allowed identification and mapping of a unique underwater landscape formed by extensive outcrops of laminated and folded lagoon marl at water depths of 5–15 m. The combined onshore–offshore database indicates that relict lagoon marl was deformed, compacted and dehydrated by a massive dune-covered coastal barrier migrating landward (retrograding) over these sediments during the Littorina Sea transgression in a processes termed ‘dune tectonics’. Spatial analysis of the relict sediments traced in offshore geophysical data helped to constrain the rates of the southeast migration of the dune massif. A conceptual model is presented to explain the present context of marl exposures above the regional water table, as well as the occurrence of relict lagoon marl extrusions (diapirs) on the underwater marine slope of the Curonian Spit.

X-ray fluorescence (XRF) core scanning has become widely available for geological studies during the last decade. The data obtained from XRF core scanning, however, may be strongly influenced by the amount of organic matter, water content, density and porosity of the sediment matrix. In this study we discuss the usefulness of XRF core scanning to distinguish different kinds of organic-rich sediments and peat based on examples from tropical Lakes Kumphawapi and Nong Leng Sai in Thailand. We examined how sedimentary factors influence XRF core scanning analyses by comparing elemental and scattering ratios to lithological changes and quantitative LOI, TOC, biogenic silica (BSi) and grain-size values. Our comparison suggests that the (inc/coh) scattering ratio is of limited use as an indicator for variations in LOI and TOC in peaty gyttja or peat. In Lake Kumphawapi's sediments, Si/Ti ratios reflect clastic input associated with grain-size variations rather than BSi contents. The Ti-normalized ratios of Si, Zr, Sr, K and Rb are linked to mineral input and associated grain-size variations. We conclude that XRF core scanning of organic-rich tropical lake sediments and peat is useful to infer palaeoenvironmental conditions. However, XRF core scanning data does not stand-alone and needs to be underpinned by additional proxies.

The development of a glacial lake impounded along the retreating, northeastern ice margin of the Fennoscandian Ice Sheet during the last deglaciation and environmental conditions directly following the early Holocene deglaciation have been studied in NE Finland. This so-called Sokli Ice Lake has been reconstructed previously using topographic and geomorphologic evidence. In this paper a multiproxy approach is employed to study a 3-m-thick sediment succession consisting of laminated silts grading into gyttja cored in Lake Loitsana, a remnant of the Sokli Ice Lake. Variations in the sediment and siliceous microfossil records indicate distinct changes in water depth and lake size in the Loitsana basin as the Sokli Ice Lake was drained through various spillways opening up along the retreating ice front. Geochemical data (XRF core-scanning) show changes in the influence of regional catchment geochemistry (Precambrian crystalline rocks) in the glacial lake drainage area versus local catchment geochemistry (Sokli Carbonatite Massif) within the Lake Loitsana drainage area during the lake evolution. Principal component analysis on the geochemical data further suggests that grain-size is an additional factor responsible for the variability of the sediment geochemistry record. The trophic state of the lake changed drastically as a result of morphometric eutrophication once the glacial lake developed into Lake Loitsana. The AMS radiocarbon dating on tree birch seeds found in the glaciolacustrine sediment indicates that Lake Loitsana was deglaciated sometime prior to 10 700 cal. a BP showing that tree Betula was present on the deglaciated land surrounding the glacial lake. Although glacial lakes covered large areas of northern Finland during the last deglaciation, only few glaciolacustrine sediment successions have been studied in any detail. Our study shows the potential of these sediments for multiproxy analysis and contributes to the reconstruction of environmental conditions in NE Finland directly following deglaciation in the early Holocene.

The Lateglacial and postglacial sequence in the northern Gulf of Riga is sedimentologically subdivided into nine distinctive layers. In the seismo-acoustic sequence these layers are correlated with seven seismic/acoustic units, which largely reflect different stages in the development of the Baltic Sea. A uniform layer of the Late Weichselian till, a layer of waterlain glacial diamicton (WGD), a varved succession of the Baltic Ice Lake, a brackish-water/freshwater sandy/silty clay of Yoldia Sea, a FeS-rich layer of Ancylus Lake and discordantly bedded sand of the Litorina Sea and present-day gyttja are revealed both in sediment cores and in acoustic recordings. In general, the lateral extent of the distinguished sediment layers is gradually shrinking upwards in the Quaternary sequence towards the deepest, central depression of the gulf. Two distinguished regional discontinuities divide the Lateglacial and postglacial sediment sequence into three allounits: glacial diamicton deposits in the lower part; ice-proximal WGD, glaciolacustrine and postglacial lake/marine deposits in the middle; and brackish-water marine deposits in the uppermost part of the sequence. The presented detailed seismostratigraphic subdivision of the Quaternary sediment sequence of the Gulf of Riga permits a correlation/comparison with similar sequences across the Baltic Sea and in other former glaciated basins.

Binka, K., Nitychoruk, J. & Dzierzek, J. 2010: Climate stability during the Eemian – new pollen evidence from the Nidzica site, northern Poland. Boreas, 10.1111/j.1502-3885.2010.00179.x. ISSN 0300-9483 Interglacial sediments at Nidzica, northern Poland were investigated by means of pollen and isotope analysis. These deposits accumulated in an extensive basin through most of the Eemian and Early Weichselian, practically without stratigraphic gaps. Continuous subsidence of the basin floor has resulted in the accumulation of a great thickness of lacustrine sediments, consisting mostly of calcareous gyttja. The course of pollen and isotope curves in the interglacial interval does not indicate the abrupt climatic shifts reported from some other continental climatic archives. Particularly important has been the reconstruction of the final stages of the Eemian, a potential analogue for future climatic change in the late Holocene. At Nidzica, this period is registered as a gradual modification of forest composition, devoid of any pulsations in which temperate forest is followed by terminal, boreal pine–birch communities.

Engels, S., Helmens, K. F., Valiranta, M., Brooks, S. J. & Birks, H. J. B. 2010: Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland. Boreas, Vol. 39, pp. 689–704. 10.1111/j.1502-3885.2010.00163.x. ISSN 0300-9483. A 25-m-long sediment record spanning the time from the Eemian to the Holocene was recovered from Sokli, northeast Finland. This study focuses on a 6-m-long sediment interval that is dated to the Early Weichselian period (MIS 5d and 5c) and consists of lacustrine and fluvial deposits. Using chironomid remains, botanical and zoological macroremains as well as sediment lithology, we were able to reconstruct past changes in the environment, including climate. The results indicate that the site was situated on a flood-plain during the latter stages of MIS 5d (Herning Stadial) and that summer temperatures might have been ∼6 °C lower than at present. Although this value should be treated with caution, as numerical analysis shows that it has a very poor fit-to-temperature, this low reconstructed value concurs with several other reconstructions that are available from western Europe. During MIS 5c (Brorup interstadial), the depositional environment changed into a lake system, initially with stratification of the water and subsequently with complete mixing and a strong influence of streams. Both chironomid-based and macroremain-based temperature inferences indicate past July air temperatures that were significantly higher than at present. This result is in contrast to other (low-resolution) reconstructions from northern Fennoscandia that indicate past temperatures 6–7 °C lower than present using fossil coleopteran assemblages. However, several central European sites indicate that there was a phase during the Brorup interstadial that was characterized by high summer temperatures, and a comparison between the high-resolution reconstructions from western Europe and the results presented in this study suggests that the north–south July air temperature gradient between the mid- and high-latitudes was much weaker during the Brorup interstadial than it is at present. High solar insolation values (particularly the obliquity) during the Brorup interstadial might explain the low summer temperature gradient over the European continent. A return to fluvial conditions occurred in the upper parts of the sediment sequence, and, after a brief interval of gyttja deposition under cooling conditions, the site became glaciated during MIS 5b.

Sediment cores from the Kriegers Flak area in the southwestern Baltic Sea show a distinct lithological succession, starting with a lower diamict that is overlain by a c. 10 m thick clay unit that contains peat, gyttja and other organic remains. On top follows an upper diamict that is inter-layered with sorted sediments and overlain by an upward-coarsening sequence with molluscs. In this paper we focus on the clay unit, which has been subdivided into three subunits: (A) lower clay with benthic foraminifera and with diamict beds in the lower part; (B) thin beds of gyttja and peat, which have been radiocarbon-dated to 31-35 14C kyr BP (c. 36-41 cal. kyr BP); and (C) upper clay unit. Based on the preliminary results we suggest the following depositional model: fine-grained sediments interbedded with diamict in the lower part (subunit A) were deposited in a brackish basin during a retreat of the Scandinavian Ice Sheet, probably during the Middle Weichselian. Around 40 kyr BP the area turned into a wetland with small ponds (subunit B). A transgression, possibly caused by the damming of the Baltic Basin during the Kattegat advance at 29 kyr BP, led to the deposition of massive clay (subunit C). The data presented here provide new information about the paleoenvironmental changes occurring in the Baltic Basin following the Middle Weichselian glaciation. (Less)

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 (Brorup) 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. (Less)

The Ferdynandovian Interglacial is one of the most controversial Quaternary stratigraphic horizons in Europe. This study concentrates on palaeoclimatic reconstruction of this interglacial based on pollen succession, isotope composition and magnetic susceptibility. The section investigated is located in the open cast mine at Belchatow, central Poland. The lacustrine sequence contains laminated diatomite at the base, which was deposited in deep, meromictic lake, and massive diatomite to calcareous gyttja in its upper part. The latter were deposited in a holomictic lake, which became progressively more shallow. The gradual increase of δ18O values and simultaneous decrease of susceptibility in the lower part of the Ferdynandovian sequence at Belchatow correspond well with climatic amelioration documented by pollen analysis. Simultaneous increase of precipitation of carbonates and its δ13C values correspond well with the increase in biological activity in the lake. Results obtained by isotope investigations showed an increase in the mean annual temperature to a maximum of 7.5°C from the beginning of the interglacial to the first appearance of thermophilous, deciduous trees. The oxygen-isotope curve does not show any short-term climatic oscillations. Susceptibility oscillations are somewhat more distinct, but because the main magnetic carrier is greigite deposited on spores of unicellular organisms, they are linked to the concentration of these spores rather than with the climatic oscillations. Twelve secular cycles or their fragments have been recorded in the interglacial sequence by palaeomagnetic investigations, suggesting c. 9600 years of deposition. This corresponds well with the 10 000 years of deposition calculated for the same sequence based on annually laminated diatomites.

Seventy-four meters of a 95-m-long drill core recovered from the Lappajarvi crater, a meteoritic impact site in western Finland, consisted of Pleistocene sediments. These sediments refer to two events of glacial deposition (Saalian and Weichselian) interrupted by non-glacigenic freshwater sedimentation. The sediments contain abundant redeposited Holsteinian and Tertiary microfossils, and possibly represent a pre-Weichselian interstadial not described from elsewhere in Finland. The pollen flora indicates a mixed primary arctic to subarctic succession that followed deglaciation, i.e. the beginning of an interglacial or interstadial event. The secondary pollen component derives from an eroded interglacial deposit that can be interpreted as Holsteinian, or possibly Eemian, in age. The vegetation succession interpreted from the primary pollen flora reflects a transition from arctic conditions to subarctic birch forests. The diatom flora indicates a primary succession that can be observed clearly in the uppermost gyttja layer in which the rich alkaliphilous diatom flora refers to more or less eutrophic conditions. The diatom flora of sediments below the gyttja layer is composed of a primary component and a secondary, redeposited or relict component. The diatoms encountered are interglacial or Tertiary in origin. The results show that meteorite craters can provide long, representative stratigraphic sequences in glacially eroded Precambrian shield areas such as Finland.

The basal 150 cm of lacustrine sediment in a 380 cm core from Pine Hill Pond, eastern Newfoundland, includes the late-glacial and early Holocene and contains strong sedirnentological and paleoecological evidence for a climatic oscillation correlative with the Younger Dryas event. Basal late-glacial minerogenic sediments are overlain by a silty gyttja marking the onset of organic sedimentation. An overlying unit comprising 7 cm of silty clay marks a return to mineral sedimentation prior to subsequent uninterrupted deposition of organic sediments. During this phase, the reversion from shrub tundra to a sparser herb-shrub tundra pollen assemblage (Oxyria digyna, Arremisia) is a strong indicator of climatic deterioration at the site. The paleolimnological expression of the Younger Dryas event at this site is manifested by a sharp decrease of diatom concentrations followed by decreases in the relative frequencies of Fragilaria spp., which are largely replaced by a stratigraph-ically restricted group of unusual benthic forms, a rise in the relative frequency of chrysophyte cysts, and a crash in Pediastrum concentrations. The nature and timing of palynological and diatom changes are interpreted in terms of both the direct and indirect consequences of climatic deterioration, as well as within the stratigraphic context of sediment lithological changes.

Samples from three different sites are dated and the results give additional evidence that radiocarbon dates of sediments containing little carbon are very often in error. It is recommended that the fraction which is soluble in NaOH be dated. The results imply that the radiocarbon ages of this fraction are very often more reliable than the insoluble fraction - at least in many Scandinavian gyttja samples.

A 56 cm long core covering ca. 9,000 years was obtained from a small, unnamed lake (78°29.5'N, 4 76°46.8'W) at 295 m elevation, innermost Baird Inlet, Ellesmere Island. The vegetation is high arctic, but locally relatively rich, with areas of Cassiope tetragona–Empetrum–Vaccinium uliginosum heath on the steep slopes above the lake. Cores were taken from the basin centre through ca. 15 m of water. Basal sandy-silt is overlain by 51 cm of laminated silty-gyttja and fine detritus gyttja grading upwards to loose algal gyttja. Three radiocarbon dates indicate rates of sedimentation from 0.07 to 0.04 mm per year. Pollen concentration varies from 1,500 to 2,000 per cm3 in the lower part of the core to 100 to 200 in the upper part; calculated pollen influx is between less than one and 14 grains per cm2 per year. Four local pollen assemblage zones reflect an early pioneer phase (grass-sedge-Oxyria) in the lowermost organic sediment, followed by the appearance and spread of Salix some 8,000 years ago and then, some 7,000 years ago, by a rise in Ericales. A period of vegetational stability with dwarf-shrub heaths follows, lasting for over 3,000 years. The topmost zone shows some increase in indicators of bare ground and fell-field vegetation (Saxifraga, Ranunculus, Papaver, Caryophyllaceae, Dryas) and decline in pollen influx, hence deterioration of local conditions during the last 3,500 to 4,000 years.

Radiocarbon datings of a 4.10 m long lacustrine sequence from Lake Ovre AErasvatn reveal continuous sediment accumulation during most of the Late Weichselian. starting before 21.800 ± 410 BP. The pollen record for the period 21,800 to 12,800 RP is uniform and is strongly dominated by Poaceae. Pollen influx variations suggest a succession of climatic ameliorations and deteriorations. Low to Middle Arctic. interstadial conditions prevailed from 21.000 to 19.650 (19.000) BP. A pronounced climatic deterioration followed. culminating at c. 18,85018,500 BP. synchronous with a glacial advance over the nearby Endletvatn and Nedre AErasvatn basins At c 18.300 BP. a climatic amelioration triggered important changes in the lacustrine environment. Organogenic gyttja (2.56 m) accumulated from 18,300 to 15,000 BP. indicating a eutrophic lacustrine environment. Sparsity of minerogenic material suggests an arid climate with low surface runoff. Further ameliorations occurred from c. 17,400 to 16,800 BP and 16,000 to 15,000 BP. From c. 15.000 BP onwards. a climatic deterioration is indicated. The 17,800 to 10,500 BP record is fragmentary. At c. 10,500 BP. an improving climate induced establishment of Betula nana –Empetrum heaths. rapidly succeeded by mesic Betula pubescens Filipendula woodlands.

A 6.5 m long sediment succession (18.5-2.2 ka BP) from the northern sub-basin of lake Endletvatn was analysed lithologically, palynologically and chemically. The chemical analyses were performed at about 10 cm depth intervals for the following parameters: total organic C, N, P, Fe, Mn, Mg, Na, K, Ca and S, in addition to water content, dry density, and pH. Two main lithostratigraphical units can be distinguished, which also differ substantially in chemical characters. Five chemostratigraphical main units were distinguished. The two lowermost units 1–2 (18.5–12.9 ka BP) correspond to the lower lithostratigraphical main unit and are characterized by minerogenous sediments with low C and N, and high Fe, Mg and K. P is low, partly because of a scarcity of P in parent rocks. Chemostratigraphical unit 3 (12.9-9.6 ka BP) is characterized by increasing C and N and a high N/P ratio (10–20) culminating in the early part of the Younger Dryas, indicating abundant N available for bio-production. The Fe, Mg, and K content is still high, but decreasing, indicating decreasing glacial and kryogenic erosion and allogenic deposition until c. 10.5 ka BP. A hiatus represented by a sand layer covers most of the time-span 10.5–9.6 ka BP. Chemostratigraphical unit 4 (9.6-5.3 ka BP) represents the Holocene thermal optimum in three subunits. In the time interval 9.6–9.1 ka BP, Fe, Mg and K decrease to a minimum and P shows a pronounced increase. The megathermal period c. 8200-5300 BP, is characterized by maxima of C, N and P and a minimum of Fe. The katathermal period after 5.3 ka BP is characterized primarily by increased Fe precipitation, increasing Fe/Mn ratio, and P, C and N at a constantly lower level than during the megathermal. A stable C/N ratio of about 10, of the sediment interval younger than 12.9 ka BP characterizes the sediments as transitional between gyttja and dy. The Holocene lake type varied between weakly oligohumic and mesohumic. Stagnant bottom waters (reducing conditions) occur in the periods 12.9–11.5 ka BP and c. 7.5-5.3 ka BP. The climatic development and other environmental implications of the joint chrono-, chemo-, litho-and biostratigraphical data set are discussed.

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 (Leveaniemi) 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.

Environmental changes were reconstructed from Lateglacial calcareous gyttja deposits at Gulickshof, southern Netherlands. Analyses of pollen, fresh-water mollusca, stable isotopes and geo-chemistry were performed and the combined evidence was put into a chronostratigraphic framework based on regional biostratigraphy and accelerator mass spectrometry radiocarbon dating. The pollen diagram showed vegetation development from the Bφlling interstadial into the Late Dryas stadial within 2.9 m of lacustrine deposits. Early in the Allerφd, around 11 900 BP, the composition of aquatic taxa and stable isotopes of calcium carbonate changed significantly. It appears that the final melting of relic ground-ice and subsequent re-establishment of the hydrological cell early in the Allerφd were responsible for these changes. Later in the Allerφd, around 11 250 BP, the disappearance of molluscs, changes in vegetation and isotope composition all point to colder climate conditions attributable to the Gerzensee oscillation. The combination of different lines of evidence in these types of deposits proves to be an excellent tool for unravelling climate and environmental signals.