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The size of the last glacial ice sheet on the Northeast (NE) Greenland shelf and its interaction with ocean circulation have been the subject of debate. Here we provide insights into the extent of the ice sheet around the Last Glacial Maximum (LGM) and investigate timing and strength of changes in the flow of Atlantic Water. The study is based on a multiproxy investigation of a marine sediment core, gravity core DA17-NG-ST01-019G, from 323-m water depth at the NE Greenland shelf edge at 79.4°N. We present benthic and planktic foraminiferal distribution data, AMS-¹⁴C dates, sedimentological (ice-rafted debris (IRD) and grain sizes), and geochemical (XRF) data in combination with geophysical (sub-bottom profiler) data. The oldest sediments at the study site are dated to 25.5–17.5 ka, encompassing the time frame from the beginning of the LGM to the early deglaciation. This part is overlain by sediments from the late deglaciation and Holocene. The deposits dating from the LGM are very rich in both planktic and benthic foraminifera and macrofossils of excellent preservation. The faunas show that the site generally was affected by a strong flow of relatively warm subsurface Atlantic Water during the LGM and Early Holocene. Conditions turned more polar with cold bottom water flow in the Middle–Late Holocene (c. 7.5 ka to Recent) with presence of mainly agglutinated benthic foraminiferal species. Our data from the LGM also indicate that the deposits were mixed by iceberg scouring, confirmed by the geophysical data showing extensive ploughing of the sediments on the outer shelf area. The results further indicate that the Greenland Ice Sheet did not reach to the edge of the NE Greenland shelf at 79.4°N during the LGM 24–18 ka.

To better understand the environmental variability during the Holsteinian interglacial, fauna of the palaeolake deposits at Ortel Królewski II, eastern Poland was investigated. The analysis covered the uppermost part of the profile, representing the so-called pre-optimal part of the Holsteinian interglacial (MIS 11c), namely the Taxus and Pinus-Larix pollen zones. Variability within the structure and composition of the faunal assemblage enabled a high-resolution palaeoecological reconstruction – lake level and temperature fluctuations, its trophy and energy of the environment. During the Taxus pollen zone the lake was relatively deep and characterized by medium trophy conditions, which is indicated by a low abundance of molluscs of temporary water bodies and low numbers of Metacypris cordata and Scottia tumida. The temperature was rather stable with only small fluctuations during the transition between the Taxus and Pinus-Larix zones. The occurrence of some cold-loving ostracod species within the beginning of the Pinus-Larix pollen zone indicates some deterioration of thermal conditions, which was additionally confirmed by using the mutual ostracod temperature range (MOTR) method. Lake level drop and expansion of reed zones within the Pinus-Larix pollen zone are inferred from the increased abundance of shallow water ostracod and mollusc species as well as from an increased Bithynia-index (BIN). The short cooling event documented early in the Pinus-Larix zone in the studied profile might be an equivalent to the mid-MIS 11c cooling, the so-called Older Holsteinian Oscillation. Thus, the improved knowledge about the climate dynamics recorded within the sediments from this site contributes to a better understanding of the spatial extent and pattern of the climatic changes within the Holsteinian interglacial across Europe.

The recurrent latent-heat polynya characterizing Storfjorden (Svalbard, Norway) triggers seasonal formation of thin first-year sea ice. This leads to the production of dense, salty, and corrosive brines that cascade towards the sea floor and mix with shelf waters. The bottom topography of the fjord is responsible for the retention of these dense waters in two central deep basins throughout the year. Recent studies show that living benthic foraminifera in Storfjorden are particularly affected by the persistence of brines on the sea floor, with a strong dominance of agglutinated (A) species and high degrees of dissolution of calcareous(C) faunas. Therefore, the A/C ratio, calculated on living faunas, was proposed as a proxy for brine persistence. In the present study we analyse the fossil faunas, found below the taphonomically active zone, to investigate the residual signal of the A/C proxy after the intense early taphonomic processes and challenge its applicability in sedimentary archives. Our results show that despite the generally high taphonomic loss inside the fjord, a high proportion of agglutinated species is still visible in fossil faunas at the stations experiencing regular and/or persistent presence of brine-enriched shelf waters. These results support the application of the A/C ratio in historical records to reconstruct the persistence of brines and indirectly the first-year sea ice formation in Storfjorden. This can be further applied to other Arctic fjords with similar settings and characterized by the production of brines during the winter–early spring season.

Cementum and dentine increment analysis was used for the first time to study the remains of cave bears from European Russia, the Urals and the Caucasus. This study analysed 12 canines belonging to 12 different individuals (five males and seven females) from genetically different lineages of cave bears. The increment analysis showed that all studied cave bears belong to the categories adults and old animals (from 10 to 32.5 years). The enamel crowns of all 12 canines were broken and/or had wear facets. Seven canines studied were severely broken (more than one-third of a canine crown missing). Significant damage to dental crowns may indicate old age, conflict between males and/or high food abrasion. The absence of significant differences in the extent of canine breakage between the youngest and the oldest animals, as well as between the males and the females, may indicate a significant role of food abrasiveness in the process of the grinding of canines. Until now, the question of whether these animals visited caves year-round or stayed there mainly for overwintering remained open. The increment analysis showed different seasons of the bears’ death. Six individuals died in the warm season and four individuals died in the cold season. In all of the studied caves (excluding Medvezhiya Cave) the animals died in the warm season as well as in the cold season. All of the studied females perished either during the cold season or at the very beginning of the warm season. On the contrary, almost all of the examined males perished in the warm season. Thus, the cave bears visited the caves year-round. This study raises new questions in the study of the ecology of cave bears from different parts of their range.

The relationship between modern pollen and vegetation provides the basis for the interpretation of stratigraphic pollen assemblages and the quantitative reconstruction of past vegetation. We selected 168 topsoil samples from four different vegetation types on the south-eastern Tibetan Plateau to explore the relationships between pollen assemblages, vegetation and climate. The results reveal that pollen assemblages discriminate the vegetation types well; the subalpine coniferous and evergreen broad-leaved forest is characterized by a high proportion of arboreal taxa (e.g. Pinus, Picea, Betula); the alpine shrub and meadow and alpine steppe vegetation types are dominated by Cyperaceae, followed by Artemisia and Brassicaceae; and the alpine steppe-shrub is characterized by a high percentage of Artemisia, with Cyperaceae, Asteraceae and Brassicaceae as common taxa. Redundancy analysis shows that mean temperature of the coldest month (Mt_co) is the main climatic factor that influences pollen distribution. Pollen diversity indices (including richness and evenness) gradually decrease from SE to NW. The random forest classification has good performance in distinguishing vegetation types. Our study supplies a comparatively detailed description of the relationship between the pollen assemblage and vegetation in the forest–meadow–steppe ecotone on the south-eastern Tibetan Plateau. In addition, the random forest model has potential application for reconstructing the past vegetation type of the fossil pollen spectra on the south-eastern Tibetan Plateau.

The sedimentary record of Icelandic ice-contact environments provides critical insights into past glacier margin dynamics and position, relative sea level, and the geomorphic processes that drive the evolution of proglacial environments. This important archive has been little exploited, however, with most glacier and sea-level reconstructions based on limited sedimentary exposures, coring and surface geomorphic evidence. We report an extensive (42 km of data within a 24-km² study area) and deep (reflections recorded at depths up to 100 m) low-frequency (40 and 100 MHz) ground-penetrating radar (GPR) survey of the Sandgígur moraines, SE Iceland. GPR profiles reveal a much larger (67 m high) and extensive (1.25 km wide) buried moraine ridge than that suggested by surface topography (typically 125 m wide and 7 m high). These data reveal that the Sandgígur moraines was deposited during a major Holocene re-advance of Skeiðarárjökull. The moraine ridge is buried by sediments dominated by glacifluvial deposits with an estimated sediment volume of 1.04 km³. We combine GPR-derived subsurface architecture and the surface morphology to develop a conceptual model detailing the geomorphic evolution of the moraine and surrounding region. These results provide new insights into the Holocene evolution of Skeiðarársandur, identifying the presence of a former major ice-margin position, as well as a past relative sea-level limit. Furthermore, we establish that sediment supply and available terrestrial accommodation space are dominant drivers in the formation and evolution of vast sandar environments.

Precipitation is a key climate parameter of vegetation and ecosystems in the Iberian Peninsula. Here, we use a regional pollen–climate calibration model and fossil pollen data from eight sites from the Atlantic coast to southern Spain to provide quantitative reconstructions of annual precipitation trends and excursions and their regional patterns for the last 11 700 years. The Early Holocene (11 700 to 11 000 cal. a BP) was characterized by high precipitation values followed by a slowly declining trend until about 9000 cal. a BP in the south and about 8000 cal. a BP in the north. From 8000 to 6000 cal. a BP the reconstructed precipitation values are the highest in most records, especially in those located in the Mediterranean climatic region in the southern part of the peninsula, with maximum values nearly 100% higher than the modern reconstructed values. The results suggest a declining precipitation during the Late Holocene in the south, with a positive excursion at around 2500 cal. a BP, while in the north precipitation remained high until 500 cal. a BP. However, the Late Holocene climate reconstructions in the Iberian Peninsula are biased by intensifying human impact on vegetation. The statistical time series analyses using SiZer technique do not indicate any statistically significant high-frequency drought events in the region. In general, our results suggest regional differences in the precipitation patterns between the northern and southern parts of the peninsula, with a more distinct Middle Holocene period of high humidity in the south.

Reconstructions of sea-surface conditions during the Holocene were achieved using three sediment cores from northeastern Baffin Bay (GeoB19948-3 and GeoB19927-3) and the Labrador Sea (GeoB19905-1) along a north–south transect based on sea-ice IP₂₅ and open-water phytoplankton biomarkers (brassicasterol, dinosterol and HBI III). In Baffin Bay, sea-surface conditions in the Early Holocene were characterized by extended (early) spring sea ice cover (SIC) prior to 7.6 ka BP. The conditions in the NE Labrador Sea, however, remained predominantly ice-free in spring/autumn due to the enhanced influx of Atlantic Water (West Greenland Current, WGC) from 11.5 until ~9.1 ka BP, succeeded by a period of continued (spring–autumn) ice-free conditions between 9.1 and 7.6 ka BP corresponding to the onset of Holocene Thermal Maximum (HTM)-like conditions. A transition towards reoccurring ice-edge and significantly reduced SIC conditions in Baffin Bay is evident in the Middle Holocene (~7.6–3 ka BP) probably caused by the variations in the WGC influence associated with the ice melting and can be characterized as HTM-like conditions. These HTM-like conditions are predominantly recorded in the NE Labrador Sea area shown by (spring–autumn) ice-free conditions from 5.9–3 ka BP. In the Late Holocene (last ~3 ka), our combined proxy records from eastern Baffin Bay indicate low in-situ ice algae production; however, enhanced multi-year (drifted) sea ice in this area was possibly attributed to the increased influx of Polar Water mass influx and may correlate with the Neoglacial cooling. The conditions in the NE Labrador Sea during the last 3 ka, however, continued to remain (spring–autumn) ice-free. Our data from the Baffin Bay–Labrador Sea transect suggest a dominant influence of meltwater influx on sea-ice formation throughout the Holocene, in contrast to sea-ice records from the Fram Strait area, which seem to follow predominantly the summer insolation trend.

The Arctic is a climate-sensitive area, responding rapidly to present changes, but for the past changes, the record is still incomplete. For instance, the Weichselian glacial history of the Svalbard–Barents Sea Ice Sheet (SBIS) has largely been reconstructed based on studies of the fragmentary Spitsbergen terrestrial and shelf records. However, the sediments removed from the land and shelf areas during peak glacials were deposited on trough mouth fans located along the continental slope. By studying the stratigraphy and processes of the trough mouth fans, comprising a more complete sediment archive, our new data have allowed gaps in the Weichselian glacial history of the SBIS to be refined and filled. Here we present new lithological and geochronological data from the Kongsfjorden Trough Mouth Fan, closely linked to the advance and decay of the SBIS. High-resolution TOPAS seismic profiles reveal three distinct packages of glacigenic debris flows (GDFs) within its upper stratigraphy, each interpreted to represent an advance of the SBIS to the shelf edge. A radiocarbon dated, 12.6-m-long core from the southern flank of the Kongsfjorden Trough Mouth Fan penetrates trough sediments directly linked to the youngest GDF package and terminates in the second GDF, allowing us to study the last two Kongsfjorden ice-stream advances in greater detail than was previously possible. The age model of core GS10-164-09PC, based on combining ¹⁴C-, ¹⁸O-stable isotope and magnetic susceptibility data, spans the last ~54 ka. An Early Weichselian glacial advance is tentatively dated to have ended at ~90 ka. A second peak glaciation is estimated at ~70 ka, followed by a deglaciation from ~54 ka. An ice rafted debris-rich unit (U7) dated between 38 and 34 ka, followed by a plumite (U6), indicates an advance of unknown extent. The Last Glacial Maximum advance is dated to before 24 ka BP, followed by a rapid deglaciation at ~15 ka. The presence of coarser-grained sorted sediments at the present seafloor is attributed to the influence of the West-Spitsbergen Current, acting on water depths of at least 846 m, and is thought to have worked in the vicinity of the coring site since ~14 ka BP.

For the first time, the Holocene history of the Serp-i-Molot tidewater glacier at the eastern side of the Novaya Zemlya archipelago, Kara Sea, has been reconstructed based on AMS ¹⁴C dating and multiproxy analyses (lithology, mineralogy, geochemistry and microfossils) of glaciomarine sediments from the Tsivol’ki Fjord. Three main phases of the Holocene evolution of the fjord environment are identified. During the early phase, c. 10.6 to 4.6 cal. ka BP, the glacier front was located close to the fjord mouth. The middle phase, c. 4.6 to 0.9 cal. ka BP, was characterized by frontal glacier retreat and shallowing of the fjord owing to glacio-isostatic uplift of the North Island of Novaya Zemlya. The late phase, from 0.9±0.1 cal. ka BP until present, reflects the stabilization of the glacier front in the inner fjord. The absence of major Neoglacial advances of the Serp-i-Molot glacier is explained by the local climate of the Kara Sea and Novaya Zemlya, which prevents the penetration of moist air flow from the North Atlantic.