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Abstract: Large areas of Montenegro were glaciated during the Pleistocene. This paper presents evidence from the massifs of central Montenegro, including Durmitor and Sinjajevina, Moračke Planine, Maganik, Prekornica and Vojnik. Glacial deposits have been subdivided on the basis of morphostratigraphy and soil weathering and 31 U-series ages from cemented tills provided a geochronological framework. The largest glaciation occurred before 350 ka when a series of conjoined ice caps over the massifs of central Montenegro covered a total area of nearly 1500 km2. These formed during MIS 12 and correspond with the largest Skamnellian Stage glaciations in Greece to the south. Later Middle Pleistocene glaciations occurred during the penultimate glacial cycle correlating with the Vlasian Stage in Greece (MIS 6) when ice caps covered an area of 720 km2 over central Montenegro. There is also geochronological evidence of glacial deposits dating from the interval between MIS 12 and MIS 6, before the interglacial complex of MIS 7. This glaciation appears to have been very similar in extent to that which occurred during MIS 6. The last glacial cycle in central Montenegro was characterised by valley and cirque glaciers covering a total area of 49 km2. It is very likely that glaciers have been present in the mountains of central Montenegro during every glacial cycle since a small glacier still survives today. The smaller glaciers of the last glacial cycle are likely to have been associated with summer temperatures that were warmer than those of earlier cold stages. The striking contrast in the extent and thickness of ice cover during the cold stages of the Pleistocene has an important bearing on the geomorphological and biological evolution of the Balkans. [Copyright &y& Elsevier]

Abstract: Sand intraclasts are common within the Bacton Green Till Member, a glacitectonic mélange subjected to polyphase deformation during the Middle Pleistocene in North Norfolk, UK. The intraclasts range from a few tens of centimetres to >10 m in length and have sharp contacts with the surrounding till. Sand within the intraclasts is unconsolidated and contains well-preserved primary stratification. The wrapping of glacitectonic foliation around the intraclasts and the development of folds relating to mechanical instabilities indicate that the intraclasts acted as competent masses within a more easily deformable fine-grained till that accommodated the majority of the strain. Sharp contacts and distinctive heavy-mineral assemblages indicate little intermixing between the sand and till. Five hypotheses about the entrainment and evolution of the intraclasts are tested against sedimentological, structural and mineralogical observations. The most reasonable hypothesis attributes the intraclasts to glacitectonic deformation of “warm” permafrost. Initial ice advance caused large-scale thrusting of proglacial permafrost that led to the stacking of pre-glacial and ice-marginal sediments that were subsequently deformed sub-marginally to generate the intraclasts. Preservation of primary stratification within the intraclasts is attributed to deformation at temperatures slightly below the pressure-melting point, when pore ice cemented the intraclasts as rigid bodies. At the same time deformation was concentrated into the surrounding finer-grained till because of its significant liquid water content and ductile rheology. It is concluded that the intraclasts provide a criterion to identify past glacier–permafrost interactions and a potential means of differentiating between subglacial deformation under unfrozen and partially-frozen conditions. [Copyright &y& Elsevier]

Abstract: Woolly mammoths were large, herbivorous, cold-adapted mammals of the Late Pleistocene. The diet and habitat requirements of the species set certain constraints on the palaeoenvironments it could occupy. The relationship between the mammoth’s shifting range and changing environments can be explored using independent data on ice sheet configuration, temperature, and vegetation, provided the locality and age of the fossil remains can be validated. Here we present a comprehensive record of occurrence of the woolly mammoth in the circum-Baltic region of northern Europe during the last glaciation, based on a compilation of radiocarbon-dated remains. The record shows that the mammoth was widespread in northern and north-eastern Europe during Marine Isotope Stage 3 (MIS 3), at 50,000–30,000 calibrated years ago (50–30ka). The presence of the species up to 65°N latitude supports the restriction of the Scandinavian Ice Sheet (SIS) during MIS 3. The widest distribution range round 30ka was followed by a decline that led to the disappearance of mammoths from the area during the maximum extent of the SIS, from 22 to 18ka. The woolly mammoth re-colonized the Baltic region and southern Scandinavia after the onset of the late-glacial deglaciation at 17ka. The late-glacial record suggests a markedly fluctuating population changing its range in tune with the rapid environmental changes. The last appearance of mammoth in our study region was in Estonia during the Younger Dryas (Greenland Stadial 1; GS1) at about 12ka. The two major periods of occurrence during MIS 3 and the late-glacial stadial suggest that mammoth had a wide tolerance of open to semi-open tundra and steppe-tundra habitats with intermediately cold climate, whereas the 22–18ka disappearance suggests a major southward and/or eastward retreat in response to extremely cold, glacial conditions near the SIS margin. The final regional extinction correlates with the re-forestation during the rapid warming at the Younger Dryas–Holocene boundary. [Copyright &y& Elsevier]

Abstract: Middle Pleistocene warm periods are particularly useful for comparison with our present warm period. One of them, Marine Isotope Stage (MIS) 11, has been considered a potential analogue for the Holocene, whereas older interglacials, e.g. MIS 13, are distinctly different. However, terrestrial Middle Pleistocene sites, other than the Holsteinian, and quantitative climate reconstructions for this period are very rare in Europe. A unique terrestrial site in North Central Europe is known from Bilshausen, Germany. The sediments are varved and indicate that this interglacial lasted ∼25,000 years, more than twice as long as the Holocene so far. The warm period probably correlates to MIS 11, or possibly to MIS 13. A new palynological investigation with large pollen counts is presented which forms the basis for quantitative temperature reconstructions based on the probabilistic indicator taxa approach (the so-called pdf-method). The range of tree species that formed the vegetation during the Bilshausen warm period is reminiscent of the Holocene, but the vegetational as well as the reconstructed climatic development shows distinct differences. No pronounced initial successional phase is recorded in the pollen stratigraphy from Bilshausen. In addition, a mesocratic or optimum phase of forest development as in the Holocene is unclear in the Bilshausen sequence. Reconstructed temperature values are several °C lower than Holocene temperatures for most of the Bilshausen interglacial. Only for several millennia in the late phase of the Bilshausen interglacial were July temperatures higher than the Holocene July temperatures. Seasonality was much stronger during the Bilshausen interglacial and the temperature trends differ between the two interglacials. Likely reasons for the pronounced differences are, on one hand, global temperature, insolation changes and atmospheric circulation. On the other hand, more regional factors such as the configuration of the North Sea basin may also be responsible for the colder winter temperatures and stronger seasonality during the Bilshausen interglacial compared to the Holocene. Reliable absolute dating of the Bilshausen interglacial is needed, which would allow a more detailed evaluation of the forcing factors that determined the climate during the Bilshausen interglacial. [Copyright &y& Elsevier]

Abstract: The Antarctic Polar Front is an important biogeochemical divider in the Southern Ocean. Laminated diatom mat deposits record episodes of massive flux of the diatom Thalassiothrix antarctica beneath the Antarctic Polar Front and provide a marker for tracking the migration of the Front through time. Ocean Drilling Program Sites 1091, 1093 and 1094 are the only deep piston cored record hitherto sampled from the sediments of the circumpolar biogenic opal belt. Mapping of diatom mat deposits between these sites indicates a glacial-interglacial front migration of up to 6 degrees of latitude in the early/mid Pleistocene. The mid-Pleistocene transition marks a stepwise minimum 7° northward migration of the locus of the Polar Front sustained for about 450 kyr until an abrupt southward return to a locus similar to its modern position and further south than any mid-Pleistocene locus. This interval from a “900 ka event” that saw major cooling of the oceans and a δ13C minimum through to the 424 ka Mid-Brunhes Event at Termination V is also seemingly characterised by 1) sustained decreased carbonate in the sub-tropical south Atlantic, 2) reduced strength of Antarctic deep meridional circulation, 3) lower interglacial temperatures and lower interglacial atmospheric CO2 levels (by some 30 per mil) than those of the last 400 kyr, evidencing less complete deglaciation. This evidence is consistent with a prolonged period lasting 450 kyr of only partial ventilation of the deep ocean during interglacials and suggests that the mechanisms highlighted by recent hypotheses linking mid-latitude atmospheric conditions to the extent of deep ocean ventilation and carbon sequestration over glacial-interglacial cycles are likely in operation during the longer time scale characteristic of the mid–Pleistocene transition. The cooling that initiated the “900 ka event” may have been driven by minima in insolation amplitude related to eccentricity modulation of precession that also affected low latitude climates as marked by threshold changes in the African monsoon system. The major thresholds in earth system behaviour through the mid–Pleistocene transition were likely governed by an interplay of the 100 kyr and 400 kyr eccentricity modulation of precession. [Copyright &y& Elsevier]

Abstract: The southeast sector of the Greenland Ice Sheet is currently experiencing rapid changes in mass balance and ice sheet dynamics at low elevations. However, to what extent these changes are typical of the behaviour of this sector of the ice sheet is uncertain, as our understanding of the longer-term controls on ice sheet dynamics in this region is limited. Two models exist for Last Glacial Maximum (LGM) ice sheet configuration in east Greenland. The first “minimum” model envisages a restricted ice sheet, with exposed nunataks in coastal areas and limited ice extent onto the continental shelf fed by ice flowing through bedrock troughs. A second, “maximum” model entails a thicker ice sheet with limited coastal nunataks, and ice filling the coastal valleys and extending across the entire continental shelf. Radiocarbon dates on foraminifera collected from seabed cores on the southeast Greenland continental shelf suggest that the ice sheet reached a maximum extent at ca 22kcal.yr, before retreating, perhaps as early as ca 17kcal.yrBP, and reaching the present coast at ca 10kcal.yrBP. This paper presents the results of a study designed to test these different ice sheet models based on geomorphological mapping and cosmogenic isotope analyses in the Torqulertivit Imiat valley, an area to the east of the coastal town of Ammassalik. 26Al and 10Be measurements on abraded bedrock surfaces in terrain above local trimlines yield surface exposure ages of ca 11.8–9.9ka. This demonstrates warm-based glacial erosion of high level surfaces (ca 740m asl), followed by trimline formation during deglaciation and intense postglacial weathering. Our work constrains minimum ice thickness during the LGM to at least 740m and supports a “maximum” ice sheet model in this sector of the GIS. Ice sheet retreat from the continental shelf to the southern edge of Sermilik Fjord is dated to ca 11.1–9.7ka and helps to constrain the timing of the early Holocene retreat of the Helheim Glacier ice stream. Within the Torqulertivit Imiat valley, age determinations from glacially abraded terrain above the local marine limit on the coast (11.1–9.7ka) and those from 10km up-valley (12.8–9.9ka), suggest rapid surface ablation during these intervals, coincident with rapid atmospheric warming observed in the Greenland ice core records. [Copyright &y& Elsevier]