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Holocene relative shore‐level changes and development of the Ģipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho‐, biostratigraphical and chronological data with remote sensing and geophysical data. The results show the development of the Ģipka basin from the Ancylus Lake/Initial Litorina Sea coastal zone (before c. 9.1 cal. ka BP) to coastal fen (c. 9.1 to 8.4 cal. ka BP) and gradual development of the Litorina Sea lagoon (c. 8.4 to 4.8 cal. ka BP) and its transition to a freshwater coastal lake (c. 4.8 to 4.6 cal. ka BP), fen (c. 4.6 to 4.2 cal. ka BP), and river floodplain (since c. 4.2 cal. ka BP). The highest shorelines of the Ancylus Lake and Litorina Sea were mapped at an elevation of 12–11 and 9 m a.s.l., respectively. A new relative shore level (RSL) curve for the western Gulf of Riga was constructed based on RSL data from the Ģipka area and from nearby Ruhnu Island studied earlier. The reconstruction shows that the beginning of the last marine transgression in the western Gulf of Riga started at c. 8.4 cal. ka BP, and concurred with the 1.9 m RSL rise event recorded from the North Sea basin. Diatom analysis results indicate the existence of the Ģipka lagoon between c. 7.7 and 4.8 cal. ka BP, with the highest salinity c. 6.1 cal. ka BP. During the existence of the brackish lagoon, settlement sites of the Neolithic hunter–gatherer groups existed on the shores of the lagoon in the period c. 6.0 to 5.0 cal. ka BP. [ABSTRACT FROM AUTHOR]

Deep Sea Drilling Program (DSDP) Site 548 was cored in 1984 at a water depth of 1256 m on the Goban Spur, offshore southwest Ireland. Coring retrieved a ~100‐m‐thick Pleistocene contourite sequence. This study uses planktonic foraminiferal assemblage and benthic foraminiferal oxygen isotope analyses to establish an age model for the upper 40 m of this core. This site's multidisciplinary analyses of planktonic foraminiferal assemblages, lithic grains, facies and calcium carbonate concentration reveal a 250 000‐year record of the North Atlantic polar front variability and British–Irish Ice Sheet (BIIS) history. The sequence is characterized by alternations of ice rafted debris (IRD) laden pelagic mud facies with calcium carbonate‐rich silty sand contourite facies that track glacial/interglacial cycles. The polar front migrated southward across the area several times during glacial maxima and stadial periods, while warmer Mediterranean Outflow Water (MOW) flowed northward across the region during interglacial and interstadial periods depositing contourites. Lithic analyses reveal a complex history of IRD deposition associated with iceberg calving from the Laurentide Ice Sheet and northwest European ice sheets, mainly the BIIS. Comparison between the Goban Spur (DSDP Site 548) and the Celtic Margin (MD03‐2692) and central North Atlantic Integrated Ocean Drilling Program (IODP) Site U1308 suggests differences between the 'non‐Laurentide Ice Sheet' Heinrich Events (HE) 6 and 3 at the Goban Spur, with IRD from the BIIS being prominent during HE 6 and IRD from other European ice sheets north of the BIIS likely being more dominant during HE 3. The nature of lithics in IRD‐rich horizons during Terminations 3, 3A, 2 and 1 suggests significant iceberg calving episodes preceding BIIS retreat during the onset of interstadial intervals. [ABSTRACT FROM AUTHOR]

The Namur area in Belgium is useful to study brown (Ursus arctos) and cave bears (Ursus spelaeus) as the assemblage contains little temporal and no geographical variation. Here, we aim to assess ontogenetic allometry within cave bears, as well as ecomorphological differences between adult brown bears (n = 9), adult cave bears (n = 5) and juvenile cave bears (n = 3). Landmarks for 3D digitization of the mandible were chosen based on the taphonomical damage of the specimens. Extant brown bears and extinct Pleistocene brown and cave bears were digitized with a Microscribe G2. Generalized Procrustes superimposition was performed on the coordinates. Allometry was studied using regression analysis. Principal component analysis (PCA) was conducted to assess ecomorphological differences between the groups. 61% of the shape variance within juvenile and adult cave bears was predicted by size (n = 8, p < 0.01). The juvenile cave bears have relatively deep horizontal rami. In adult cave bears, the horizontal ramus is much narrower dorsoventrally. Juvenile cave bears have a small masseteric fossa and a short coronoid process, whereas both are larger, relative to mandible size, in adult cave bears. This made juvenile cave bears likely less effective masticators than fully grown cave bears. In the PCA, principal component (PC) 1 accounts for 45.0% of the total variance and PC2 accounts for 27.6%. Fossil U. arctos from Namur fall within the 95% confidence interval of modern North American U. arctos on both PCs, but are more similar to cave bears than the average extant brown bear. From the similarity of fossil and modern brown bears, it can be deduced that the diet of fossil brown bears was probably also within the range of their modern North American conspecifics, although they might have been more efficient at masticating plant matter. [ABSTRACT FROM AUTHOR]

Extensive fires pose catastrophic threats to both human and natural ecosystems. Understanding the history of fire, particularly Holocene palaeofire activity in densely populated areas, is essential for predicting future fire risks and developing effective fire management policies. The complexity of fire activity is influenced by various factors, including climate and anthropogenic activities. In this study, we analysed microcharcoal from the top 35.36 m of a well‐dated sediment core HMD1401 in Ningshao Plain, eastern China. We combined our findings with phytolith and diatom evidence to obtain a comprehensive understanding of variations in Holocene fire activity and its controls. The results showed that there was higher fire activity during the early and late Holocene and less fire activity during the mid‐Holocene. More frequent fire occurred from c. 10 000–7000 cal. a BP and was primarily caused by abundant biomass and high seasonal flammability due to increased annual temperature and precipitation and warm but dry winter climate. Fire occurrences between c. 7000–2000 cal. a BP remained at a low level, except for the periods c. 5900–5600 cal. a BP and c. 5300 cal. a BP, which may have been caused by extreme climate events. The impact of fire caused by human activity was significantly enhanced during the last two millennia. [ABSTRACT FROM AUTHOR]

Recent investigations into relict periglacial phenomena in northern and western China and on the Qinghai- Tibet Plateau provide information for delineating the extent of permafrost in China during the Late Pleistocene. Polygonal and wedge-shaped structures indicate that, during the local Last Glacial Maximum ( LLGM, between ∼35 and 10.5 ka BP), the southern limit of latitudinal permafrost in northern China advanced southward at least to ∼38-40° N in the east and to ∼37-39° N in the west. This represents an advance of about 5-10° of latitude beyond present-day permafrost limits. The lower limits of elevationally controlled permafrost on the Qinghai- Tibet Plateau and its peripheries were about 1000 m lower: this permafrost was largely continuous during the LLGM. This suggests a cooling of between 4 and 10° C, or more. This paper discusses the extent of permafrost during the LLGM and presents maps that have been constructed on the basis of extensive and integrative analysis of all reliable and pertinent data. The results indicate that the extent of LLGM permafrost in China was between ∼3.8 and 4.3×106 km2. This is 80 to 100% more than that of ∼2.15×106 km2 in the 1970s, and 120 to ∼150% more than that of ∼1.75×106 km2 today. [ABSTRACT FROM AUTHOR]

This paper presents three maps that summarize current knowledge as to the extent of Past permafrost and Relict permafrost in North America at approximately the time of the Last Glacial Maximum ( LGM; c. 25-17 ka BP) and during subsequent deglaciation until c. 10 ka BP. Analysis of the post-1983 literature suggests that the extent of Past permafrost south of the LGM limit was broader in eastern North America and slightly narrower in the Interior Great Plains than previously mapped. The recognition and dating of Relict permafrost in the nonglaciated terrain of the northwestern Arctic suggests that permafrost may be of great antiquity and can persist under changing climatic conditions. The formation of permafrost features during deglaciation suggests that ice-proximal climatic conditions remained cold at least long enough for short-lived permafrost aggradation; a latitudinal gradient is evident in the timing of its development as the Laurentide Ice Sheet retreated. [ABSTRACT FROM AUTHOR]

Reindeer ( Rangifer tarandus) populations reached the Iberian Peninsula during the end of the Middle Pleistocene and there are numerous examples of this species from Late Pleistocene Mousterian and Upper Palaeolithic sites. In this paper, new evidence of reindeer in the east Cantabrian region is presented that further supports the timing of this species' first appearance, and previous assessments are updated. To date, the presence of this species has been identified at 55 sites in the Iberian Peninsula, nearly as many as those of mammoth ( Mammuthus primigenius) and woolly rhinoceros ( Coelodonta antiquitatis) combined. Most of the sites with presence of reindeer (50) are located in the Cantabrian region with a clear increase in the density of sites and remains towards the Pyrenees. The remaining five sites with evidence of reindeer are located on the other side of the Pyrenees in the NW corner of Catalonia. In contrast, archaeological evidence of reindeer in the form of art (both parietal and portable) is more scarce and scattered. Evidence for the representation of these animals has been found outside the northern fringe of the Iberian Peninsula, which could reflect either long-distance cultural communication or the movement of human groups. [ABSTRACT FROM AUTHOR]

In the present paper the effects of rapid, high-amplitude base-level changes during the last glacial-interglacial transition were studied for the Ain River in eastern France. During the Würm glacial maximum ( MIS 2) rapid aggradation by deep-water Gilbert-type deltas and shallow-water fan deltas occurred at the margins of a 20 to 50 m deep proglacial lake. A temporal high-amplitude lake-level fall of 60 m resulted in gravel deposition by forced-regressive deltas, followed by rapid lake-level rise and fine-grained glaciolacustrine deposition. During the final deglaciation, a rapid base-level fall of 40 m resulted in a complex fluvial response. Knickpoint formation and headward incision of the highstand deltas and concomitant deposition of gravel sheets by forced-regressive deltas and braided systems occurred in several depocentres on the former glacial lake floor. Preservation of highstand and falling-stage deposits and terrace formation in the incised valley depended on vertical incision and lateral channel migration. Terraces are well developed in the former lake-floor depressions, whereas vertical incision was dominant in the higher lake-floor areas. The Ain terrace staircase was likely formed by autogenic processes during a single allogenic base-level fall. This case study possibly offers an analogue for the preservation of interglacial highstand coastal deltas during sea-level fall at warm-to-cold climate transitions, although the rates of base-level fall are different. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper focuses upon the youngest terraces of the Moselle and its tributary the Meurthe ( NE France and SW Germany). It includes research on several sections, in particular the key sections of Golbey- Pré Droué and Thörnich- Hochrech (located in the vicinity of the Vosges Massif and in the Rhenish Massif, respectively), and the use of the Optically Stimulated Luminescence ( OSL) dating method. Our investigations made it possible to obtain a more robust chronostratigraphical framework and to update the previous model of fluvial response to climate change. The results demonstrate that the Moselle terrace M3 (first terrace formed after the capture of the Upper Moselle by the Palaeo- Meurthe) has the same age from the Vosges to the Rhenish Massif. The formation of this terrace included two main periods of sedimentation attributed to the Late Saalian ( MIS 6) and the Early Weichselian ( MIS 5), respectively. They were separated by a major episode of fluvial erosion that may be allocated to the MIS 6-5 transition on the basis of chronological and sedimentological evidence. This erosion led to the removal of most of the MIS 6 deposits, whereas the MIS 5 deposits have been widely preserved following the subsequent ( MIS 5-4) terrace incision. This evolution somewhat contrasts with that observed in the Sarre valley, the main tributary of the Moselle, and with many fluvial systems in western Europe, which show better preservation of deposits from cold periods. This atypical behaviour is explained by the relationship between the fluvial evolution and the glaciers covering the upper Moselle catchment ( Vosges Massif) during the Pleistocene cold periods. [ABSTRACT FROM AUTHOR]

This paper presents the first integrated macroscale and microscale examination of subglacial till associated with the last-glacial ( Fraser Glaciation) Cordilleran Ice Sheet ( CIS). A new statistical approach to quantifying till micromorphology (multivariate hierarchical cluster analysis for compositional data) is also described and implemented. Till macrostructures, macrofabrics and microstructures support previous assertions that primary till in this region formed through a combination of lodgement and deformation processes in a temperate subglacial environment. Macroscale observations suggest that subglacial environments below the CIS were probably influenced by topography, whereby poor drainage of the substrate in topographically constricted areas, or on slopes adverse to the ice-flow direction at glacial maximum, facilitated ductile deformation of the glacier bed. Microscale observations suggest that subglacial till below the CIS experienced both ductile and brittle deformation, including grain rotation and squeeze flow of sediment between grains under moist conditions, and microshearing, grain stacking and grain fracturing under well-drained conditions. Macroscale observations suggest that ductile deformation events were probably followed by brittle deformation events as the substrate subsequently drained. The prevalence of ductile-type microstructures in most till exposures investigated in this study suggests that ductile deformation signatures can be preserved at the microscale after brittle deformation events that result in larger-scale fractures and shear structures. It is likely that microscale ductile deformation can also occur within distributed shear zones during lodgement processes. Cluster analysis of microstructure data and qualitative observations made from thin sections suggest that the relative frequency of countable microstructures in this till is influenced by topography in relation to ice-flow direction (bed drainage conditions) as well as by the frequency and distribution of voids in the till matrix and skeletal grain shapes. [ABSTRACT FROM AUTHOR]

The paper summarises materials on the mammal remains in northeastern Europe, dated by radiocarbon. Altogether, 23 local faunas of small mammals and 47 local faunas of large mammals were analysed. Multidimensional statistical analysis shows a strong correlation between changes in small mammal fauna composition and climate changes throughout time. The correlations with the spatial gradients, however, are less pronounced. The faunas are classified into three groups: (1) faunas of Holocene age; (2) Late Pleistocene 'stadial' assemblages; and (3) Late Pleistocene 'interstadial' assemblages. In some cases, changes in species abundance are better understood in terms of biotic interrelations rather than of climatic effects. The most pronounced change in small mammal fauna composition and structure occurred at the Preboreal/ Boreal boundary, and a less conspicuous alteration took place at the LGM/Lateglacial transition. The most noticeable transformation in the large mammal fauna composition is dated to the early Holocene. Less significant changes are observed at the Middle Weichselian/ LGM transition and at the LGM/Lateglacial transition. It is safely concluded that variations in the faunas of small and large mammals recorded in NE Europe during the last 35 000 years occurred synchronously and unidirectionally. [ABSTRACT FROM AUTHOR]

Thermokarst ponds are widespread in arctic and subarctic regions, but little is known about their temporal evolution prior to human observations. This paper presents a pioneer biostratigraphic study conducted at a subarctic site with limnologically contrasted ponds located on the eastern shore of Hudson Bay, Canada. Fossil diatom and visible near infrared ( VNIR) derivative spectral analyses were performed on short sediment cores, confirming the occurrence of three distinct stratigraphic facies as already inferred from an anterior sedimentological study: a lacustrine upper facies ( UF) and a marine lower facies ( LF), separated by an organic-rich/peat transitional zone ( TZ). Diatoms were almost absent from LF, but increased significantly in both TZ and UF. Identified diatom taxa were mainly benthic species (e.g. genera Fragilaria, Pinnularia), and their down-core distribution appeared to be related to dissolved organic carbon ( DOC) and possibly pH conditions. Diatom-inferred DOC showed a decreasing trend towards the surface (potentially associated with an increase in pH), inverse to the general trend in this region, suggesting the action of other mechanisms on DOC, such as exhaustion of external inputs from limited catchments and the role of discontinuous peat layers (former surfaces of permafrost mounds) during the initial stages of pond formation. These bryophilous substrates in aerophilic habitats probably controlled diatom community composition. The combination of diatom and VNIR data revealed similar trends between (i) opal (amorphous silica) and diatom abundances; (ii) eukaryotic/prokaryotic algae ratio and anoxia or hypoxia in bottom waters; and (iii) limonite (iron oxide) and redox conditions in surface sediments. These findings indicate that diatom community changes and pond limnological evolution in the recent past were controlled mainly by autogenic processes (e.g. local vegetation/soil development, peat accumulation and erosion), rather than by allogenic forcing mechanisms (e.g. precipitation and temperature, geochemical leaching of the surrounding glaciomarine sediments). [ABSTRACT FROM AUTHOR]

This paper describes and discusses the palaeobotanical data obtained from organic levels of two exposed deposits on the Atlantic shore of the northwestern Iberian Peninsula. Radiocarbon dating assigns these levels to a period of marine regression at the end of MIS 3 and the beginning of the Last Glacial Maximum. The pollen record shows an initial predominance of tree taxa (mainly deciduous, including the presence of Fagus far from its current limit), followed by an episode of partial forest retraction related to the end of MIS 3 and the beginning of the Last Glacial Maximum. However, the presence of numerous tree taxa in the record, even during the cold intervals associated with Heinrich events, points to the existence of sheltered refugia for these species during this period, in keeping with the conclusions of recent reviews of the vegetation dynamics of this region for the Lateglacial and the Holocene. [ABSTRACT FROM AUTHOR]

It is a scientist's mission to try to remain unbiased. However, certain factors play a role in scientific analyses that are not controlled by conscious thought. These factors are potentially very important in areas of science where interpretations are based on a scientist's ability to identify patterns or structures. One such area is the micromorphology of glacial sediments. In this paper we investigate the role of an analyst's experience in relation to pattern perception with specific reference to turbate microstructures in glacial diamictons. An experiment was conducted on 52 participants, which demonstrated that, as may be expected, more experienced (glacial) micromorphologists tend to exhibit a higher sensitivity-to-signal, but that complete novices, if given clear instructions, can reach levels of sensitivity similar to those of experts. It also showed, perhaps more surprisingly, that response bias does not decrease with experience. We discuss psychological factors, such as the drive for success and consistency, that may have contributed to these results and investigate their possible implications in the micromorphological analysis and interpretation of glacial sediments. [ABSTRACT FROM AUTHOR]

The varved sediment of Lake Suigetsu (central Japan) provides a valuable opportunity to obtain high-resolution, multi-proxy palaeoenvironmental data across the last glacial/interglacial cycle. In order to maximize the potential of this archive, a well-constrained chronology is required. This paper outlines the multiple geochronological techniques being applied - namely varve counting, radiocarbon dating, tephrochronology (including argon-argon dating) and optically stimulated luminescence ( OSL) - and the approaches by which these techniques are being integrated to form a single, coherent, robust chronology. Importantly, we also describe here the linkage of the floating Lake Suigetsu ( SG06) varve chronology and the absolute ( Int Cal09 tree-ring) time scale, as derived using radiocarbon data from the uppermost (non-varved) portion of the core. This tie-point, defined as a distinct (flood) marker horizon in SG06 (event layer B-07-08 at 1397.4 cm composite depth), is thus derived to be 11 255 to 11 222 Int Cal09 cal. years BP (68.2% probability range). [ABSTRACT FROM AUTHOR]

The ability of glaciers to detach and transport bedrock as glaciotectonic rafts is widely observed throughout Quaternary sections. However, the glaciological, hydrological and geological parameters controlling rafting are currently poorly constrained. There is a lack of structural and sedimentary evidence concerning rafting, and therefore the processes driving raft detachment, transport and emplacement are poorly understood. This paper contributes to our understanding by presenting a macro- and microstructural study of deformation associated with a chalk raft at West Runton, north Norfolk. Detailed thin-section analysis reveals several discrete micro-fabric orientations, representing poly-phase deformation occurring during raft transport and emplacement. A four-stage conceptual model for raft transport and emplacement is proposed, with deformation being partitioned into the relatively weaker Happisburgh Till member, the latter forming the host to the raft. Stage 1 is the main transport phase of the chalk raft, and was dominated by easterly (down-ice) directed ductile shearing. During Stage 2 a narrow ductile shear zone within the Happisburgh Till member propagated upwards through the base of the raft, leading to the detachment of an elongate block of chalk. Attenuated lenses of diamicton in this shear zone possess kinematics recording an easterly directed sense of shear. As deformation progressed, during Stage 3, the detached block impinged on the 'high-strain' zone wrapping the base of the raft, influencing the style of deformation partitioning and leading to localized, up-ice-directed kinematics. Stage 4 represents the final stages of raft emplacement, when the detachment zone at the base of the raft began to 'lock-up'. These results demonstrate the relative importance of the hydrological controls associated with raft transport and emplacement underneath an actively advancing glacier. Furthermore, the model represents an example of how micromorphological analysis can reveal detailed poly-phase deformation histories in deformed glacial sediments. [ABSTRACT FROM AUTHOR]

Throughout northern Canada, live-collected, pre-bomb, deposit-feeding marine molluscs from calcareous sediments yield greater apparent radiocarbon ages than do suspension feeders. We explore the size of this effect in a set of 57 paired datings of deposit feeders, mainly Portlandia arctica, and suspension feeders, mainly Hiatella arctica and Mya truncata, collected from both calcareous and non-calcareous Holocene sediments. Deposit feeders from calcareous sediments are older than their suspension-feeding counterparts by as much as 2240±130 14 C years. This is attributed to the uptake of 'old' bicarbonate derived from calcareous bedrock. The age discrepancy between suspension and deposit feeders in calcareous terrain is non-systematic in space and time, thereby invalidating the application of a correction. In contrast, the age comparisons are concordant at sites located on the Precambrian Shield. In terrestrial environments underlain by carbonate, previous acceptance of dates on deposit feeders led to erroneous interpretations of deglaciation and relative sea-level history, in both the North American and the Eurasian Arctic. This has prompted several researchers to exclude deposit feeders from their late Quaternary reconstructions. The same chronological problem of deposit-feeding molluscs now needs to be more widely acknowledged by the marine community. [ABSTRACT FROM AUTHOR]

Tunnel valleys are common throughout the terrain of the Saginaw Lobe of the Laurentide Ice Sheet in southern Michigan. The set of valleys described in this paper is regularly spaced in a radial pattern behind the Kalamazoo Moraine, an ice-marginal position formed during retreat from the Last Glacial Maximum. These valleys are divided into proximal and distal groups lying north and south, respectively, of a major river valley that cross-cuts the tunnel valleys at right angles. Based on a series of rotasonic borings and core analysis, the proximal valleys are shallow, contain minimal sediment fill, and overlie fine-grained diamicton and glaciolacustrine sediment, whereas the distal valleys are deeply incised into the substrate and are partially filled with coarse sediment. The distal valleys terminate within a broad zone of high-relief, hummocky topography representing stagnation and collapse behind the Kalamazoo ice margin. The proximal valleys occur within a more subdued landscape located farther from the ice margin. Although some elements of existing genetic models are consistent with these valleys, none appears to be completely compatible with their stratigraphy and morphology. Initial incision of the valleys could have involved short-lived moderate- to high-discharge flows, followed by deposition during or after the events. The deep incision and thick, coarse sediment in distal valleys in the stagnant marginal zone probably involved supraglacial meltwater draining to the bed as the margin downwasted. Fining-upward eskers inset into the valleys were formed by flows of declining energy in small late-stage conduits. [ABSTRACT FROM AUTHOR]

A marine geophysical study reveals a complex deglaciation pattern in the Kveithola trough, W Barents Sea. The data set includes multibeam swath bathymetry and sub-bottom sediment profiler (chirp) data acquired for the whole extent of a palaeo, marine-terminating ice stream, along with high-resolution single-channel seismic data from chosen profiles. The multibeam data show a geomorphic landform assemblage characteristic of ice streams. The results of a combination of seismic and chirp unit stratigraphy reveal that the seabed geomorphology is governed by a deeper-lying reflector. The reflector dominates surface expressions of several subglacial and ice-marginal units, each connected to a separate episode of ice-margin stillstand/advance. Analysis of the combined data set has resulted in a conceptual model of the ice-stream retreat. The model depicts complex deglaciation of a small, confined ice-stream system through episodic retreat. It describes the formation of several generations of grounding-zone systems, characterized by high meltwater discharges and the deposition of fine-grained grounding-line fans. The inferred style of grounding-zone deposition in Kveithola deviates from that of other accounts, and is suggested to be intermediate in the previously described continuum between morainal banks and grounding-line wedges. The results of this paper have implications for grounding-zone theory and should be of interest to modellers of grounding-line dynamics and ice-stream retreat. [ABSTRACT FROM AUTHOR]

The size, age and dynamics of Pleistocene glaciers, especially ice sheets that periodically covered the northern seaboard of Eurasia, are crucial for understanding the evolution of arctic climates, sea-level changes, the biota and tectonism. General ideas on the glacial history of the vast areas of northern Russia between 48° and 148° E, beyond the limits of the Fennoscandian glaciation, have considerably changed during the last two decades. The change towards modern views may even be considered as a paradigm shift from the conventional wisdom of the previous half-century. The transformation of the main landmarks of late Quaternary glacial history started in the 1970s and accelerated after 1993 as a result of international collaboration in the Russian Arctic. A wealth of new sedimentological, geomorphic and stratigraphic data has recently accumulated for the sedimentary record of the last 200 ka. This information, together with data collected from native geological surveys, has been synthesized in the form of digital maps of ice limits based on key stratigraphic sites. The results have been published as contributions to the international programs QUEEN and APEX and also as parts of global compilations. These publications give general overviews of the Eurasian glacial history, but some important modern data are reported only in the Russian literature and therefore are hardly known to the international community. In this paper I will first consider the background material on the non- Scandinavian glaciations and then follow this with a review of the modern results obtained in the course of international cooperation. The outcome is inevitably influenced (or biased) by my long-term experience in studying the Pleistocene of northern Russia. I will not discuss here the extreme northeast of Siberia (western Beringia), as this is a distinct topic partly overviewed in recent publications. [ABSTRACT FROM AUTHOR]

As a result of global changes, shifts of alpine tree lines towards higher elevations have been recorded, but the role of the spatial variability of the snowpack and zonal-pattern soil-nutrient regimes is poorly understood. Norway spruce ( Picea abies ( L.) Karst) is best suited to fertile soils, and hence we applied soil physical-chemical and snow measurements and the age chronology of Norway spruce along an elevational gradient (380-557 m a.s.l.) to address a vertical soil zonality hypothesis on mafic Lommoltunturi fell in Finnish Lapland. With regard to increasing elevation, we found an increase in soil NTOT, CTOT and Al, but a decrease in soil Ca, Mg and Ca: Al ratio as well as in electrical conductivity ( EC). In addition, the snowpack was significantly thicker in low-elevation forest than in the tree line and open tundra. In the 1840s, spruce established on low-elevation soils with a Ca: Al ratio of 2.2. Starting from the 1920s a significant shift of spruce occurred such that it took 60 years to expand the tree line by 55 m in elevation. The spruce tree line has advanced, and the age distribution indicates new colonization of spruce in closed forest up to tundra. The poor soil Ca: Al ratio of 0.02 on tundra apparently is a constraint for spruce. Spruce forest is young (<165 years), and hence we argue that spruce has expanded onto formerly tree-free sites of this mafic fell. This paper demonstrates that vertical soil zonality is a potential driver for the diffuse tree line of Picea abies on mafic Fennoscandian fells. [ABSTRACT FROM AUTHOR]

This paper presents the first detailed sedimentological study of annual moraines formed by an alpine valley glacier. The moraines have been forming since at least AD 1980 by a subsidiary lobe of Gornergletscher, Switzerland that advances up a reverse bedrock slope. They reach heights of 0.5-1.5 m, widths of up to 6 m and lengths of up to several hundreds of metres. Sediments in these moraines are composed of proglacial outwash and debris flow units; subglacial traction till is absent entirely. Based on four representative sections, three genetic process combinations have been identified: (i) inefficient bulldozing of a gently sloping ice margin transfers proglacial sediments onto the ice, causing differential ablation and dead-ice incorporation upon retreat; (ii) terrestrial ice-contact fans are formed by the dumping of englacial and supraglacial material from point sources such as englacial conduit fills; debris flows and associated fluvial sediments are stacked against a temporarily stationary margin at the start, and deformed during glacier advance in the remainder, of the accumulation season; (iii) a steep ice margin without supraglacial input leads to efficient bulldozing and deformation of pre-existing foreland sediments by wholesale folding. Ice-surface slope appears to be a key control on the type of process responsible for moraine formation in any given place and year. The second and third modes result in stable and higher moraines that have a higher preservation potential than those containing dead ice. Analysis of the spacing and climatic records at Gornergletscher reveals that winter temperature controls marginal retreat and hence moraine formation. However, any climatic signal is complicated by other factors, most notably the presence of a reverse bedrock slope, so that the extraction of a clear climatic signal is not straightforward. This study highlights the complexity of annual moraine formation in high-mountain environments and suggests avenues for further research. [ABSTRACT FROM AUTHOR]

The Cova dels Xaragalls is a small open karst system, located in the municipality of Vimbodí-Poblet ( Tarragona, Catalonia, NE Spain). It is an important Holocene archaeological site that was inspected in the 1970s but from which little has been published. New excavations starting in 2008 have exposed a deep Late Pleistocene stratigraphical sequence. In this paper, we present for the first time palaeoenvironmental and palaeoclimatic reconstructions of this Late Pleistocene succession on the basis of both the small-vertebrate assemblages and the charcoals. Results from the small-vertebrate associations along the sequence indicate that the landscape had open-woodland habitats in the vicinity of the Cova del Xaragalls, with wet points in the surrounding area. Woodland habitats were dominant throughout the sequence, as evidenced by the abundance of the species Apodemus sylvaticus, but were better developed during warm periods (layers C5 and C8), whereas during cold periods (layers C4 and C3) the environment was slightly more humid in response to higher mean annual precipitation and the opening of the landscape. The charcoal analysis indicates that the woodland surrounding the cave was composed mainly of Pinus (more than 90% was identified as Pinus), but that during the cold period ( C3- C4) it incorporated some Quercus ilex/ coccifera and Angiosperm indet., probably linked with greater precipitation. Comparisons are made with other long palaeoenvironmental sequences from the northeastern Iberian Peninsula and with global marine isotopic curves, providing a scenario for the palaeoclimatic and palaeoenvironmental changes that occurred during the Late Pleistocene in the woodland areas surrounding the Cova dels Xaragalls. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive palaeoenvironmental data set from Lake Skrzynka, northern Poland. A sediment core from the lake was investigated to reconstruct Lateglacial and Holocene environmental changes in northern Poland using a combination of palynology and stable carbon and oxygen isotope studies of carbonates and sediment geochemistry. The undisturbed sedimentation in Lake Skrzynka continues from the Allerød to the present. Our data suggest the persistence of dead ice in the Lake Skrzynka basin up to the Allerød. The sedimentary record of the lake reflects a considerable difference between the Lateglacial/early Holocene and the middle/late Holocene in terms of environmental conditions. The Lateglacial was characterized by rapid environmental changes, while climatic conditions throughout the Holocene were relatively stable. The trophic state of the lake was strictly dependent on climatically controlled vegetation changes and erosion tendencies in the vicinity of Lake Skrzynka. During the Lateglacial and early Holocene, as a result of predominantly open plant communities and enhanced nutrient export from the watershed, Lake Skrzynka experienced an increased trophy. The stabilization of forest cover and reduced input of nutrients resulted in the establishment of oligotrophic conditions in the lake in the early Boreal. During the late Subatlantic, the lake became eutrophic as a result of human disturbance of the local hydrological balance. The postglacial history of Lake Skrzynka can be regarded as representative of small, alkaline, through-flow lakes in temperate climates. [ABSTRACT FROM AUTHOR]

An overstepped, concave‐eastward, barrier beach beneath Holocene mud in western Lake Ontario has been delineated by acoustic and seismic reflection profiles and piston cores, and related to Early Lake Ontario (ELO). The average ELO barrier depth below present mean lake level is 77.4 to 80.6 m, or about −6 to −2.8 m above present sea level. Trend surface analysis of Champlain Sea (Atlantic Ocean) marine limits defined the contemporaneous marine water surface, and projections of this surface pass ~25 m above the outlet sill of the Lake Ontario basin and extend to the ELO palaeo‐barrier, a unique sand and gravel deposit beneath western Lake Ontario. ELO was connected to the Champlain Sea above the isostatically rising outlet sill for up to three centuries after about 12.8 cal. ka BP, while the glacio‐isostatically depressed St. Lawrence River Valley was inundated by the Atlantic Ocean. During the period of this connection, ELO level was confluent with slowly rising sea level, and the lake constructed a transgressive beach deposit with washover surfaces. ELO remained fresh due to a high flux of meltwater inflow. The marine water level connection stabilized water level in ELO relative to its shore and facilitated shore erosion, sediment supply and barrier construction. Glacio‐isostatic uplift of the outlet sill, faster than sea‐level rise, lifted ELO above the Champlain Sea about 12.5 cal. ka. Shortly after, a hydrological deficit due mainly to a combination of diverted meltwater inflow and dry climate, well known from regional pollen studies, forced the lake into a lowstand. The lowstand stranded the barrier, which remains as evidence of sea level, the farthest inland in eastern North America north of the Gulf of Mexico at the time. The highest palaeo‐washover surface provides a sea‐level index point. [ABSTRACT FROM AUTHOR]

Baeteman, C., Waller, M. & Kiden, P. 2011: Reconstructing middle to late Holocene sea-level change: A methodological review with particular reference to 'A new Holocene sea-level curve for the southern North Sea' presented by K.-E. Behre. Boreas, 10.1111/j.1502-3885.2011.00207.x. ISSN 0300-9483. A number of disciplines are involved in the collection and interpretation of Holocene palaeoenvironmental data from coastal lowlands. For stratigraphic frameworks and the assessment of relative sea-level (RSL) change, many non-specialists rely on existing regional models. It is, however, important that they are aware of major developments in our understanding of the factors controlling coastal change and of the potential sources of error in sea-level reconstructions. These issues are explored through a critical evaluation of a new sea-level curve presented by for the southern North Sea. In contrast to most sea-level curves published from this region over the last 20 years, the curve shows strong fluctuations that are interpreted as representing vertical movements of sea level. We present a detailed examination of the data used by Behre. From this analysis it is clear that many of the data points used are unsuitable for high-resolution (centimetre or decimetre) sea-level reconstruction. This paper also gives an overview of possible sources of error with respect to the age and altitude of sea-level index points and of changes in our understanding of the processes that underpin the interpretation of the organic and occupation levels used as index points. The constraints on the spatial scale over which sea-level reconstructions can be applied (changes in palaeotidal range and crustal movements) are also considered. Finally, we discuss whether the large-amplitude centennial-scale sea-level fluctuations proposed by Behre can be reconciled with the known mechanisms of sea-level change and other recent high-resolution studies from this region. We conclude that such fluctuations are highly unlikely to be real features of the sea-level history of the southern North Sea. [ABSTRACT FROM AUTHOR]

Corona, C., Edouard, J.-L., Guibal, F., Guiot, J., Bernard, S., Thomas, A. & Denelle, N. 2010: Long-term summer (AD751-2008) temperature fluctuation in the French Alps based on tree-ring data. Boreas, 10.1111/j.1502-3885.2010.00185.x. ISSN 0300-9843. On the basis of a dense tree-ring width network (34 unpublished multi-centennial larch chronologies), this paper attempts to reconstruct, for the first time, the summer temperatures in the French Alps (44°-45.30°N, 6.30°-7.45°E) during the last millennium. The adaptative Regional Growth Curve standardization method is applied to preserve interannual to multi-centennial variations in this high-elevation proxy data set. The proxies are calibrated using the June to August mean temperatures from the last revised version of the HISTALP database spanning the period AD1760-2003 and adjusted to take into account the warm bias before 1850. About 45% of the temperature variance is reconstructed. Despite the use of the newly updated meteorological data set, the reconstruction still shows colder temperatures than early instrumental measurements between 1760 and 1840. The proxy record evidences a prolonged Medieval Warm Period persisting until 1500, with warm periods that resemble 20th century conditions but also cold phases before 1000 synchronous with Swiss glacier advances. The Little Ice Age is rather mild until 1660 if compared with other Alpine reconstructions. Thereafter, summers are 0.7 °C cooler than the 1961-1990 mean until 1920. The maximum temperature amplitude over the past 1250 years is estimated to be 3 °C between the warmest (810s, 1990s) and coldest (1810s) decades. Most of the 20th century is comparable with the Medieval Warm Period. [ABSTRACT FROM AUTHOR]

Batina, M. C. & Reese, C. A. 2010: A Holocene pollen record recovered from a guano deposit: Round Spring Cavern, Missouri, USA. Boreas, 10.1111/j.1502-3885.2010.00186.x. ISSN 0300-9483. Bat guano deposits have been the subject of relatively few palynological studies. The studies to date have focused on the most modern samples only, and therefore the full potential of bat guano as an archive for fossil pollen analysis remains unknown. In this paper we report the results of pollen analysis on an 88-cm vertical profile of fossil bat guano from Round Spring Cavern, Missouri. Four AMS radiocarbon dates were in sequence and showed that the guano pile was active between 8155 and approximately 550 cal. yr BP. Pollen is well preserved throughout the profile, with most samples containing less than 10% indeterminable pollen. Wind-pollinated taxa are better represented than insect-pollinated taxa, and pollen concentrations range from 842 to 371 660 grains cm. As expected, the dominant vegetation types represented by the pollen assemblage are oak and pine, in accordance with the region's oak-hickory-pine forest. However, there are discrepancies between the guano pollen record and the results of a lake pollen study conducted in southern Missouri. We propose several possible factors that may be influencing the guano pollen record and provide direction for further investigation into the palaeoecological potential of bat guano. [ABSTRACT FROM AUTHOR]

Buylaert, J.-P., Huot, S., Murray, A.S. & Van den haute, P.: Infrared stimulated luminescence dating of an Eemian (MIS 5e) site in Denmark using K-feldspar. Boreas, 10.1111/j.1502-3885.2010.00156.x. ISSN 0300-9483. Infrared stimulated luminescence (IRSL) dating of K-feldspars may be an alternative to quartz optically stimulated luminescence (OSL) dating when the quartz OSL signal is too close to saturation or when the quartz luminescence characteristics are unsuitable. In this paper, Eemian (MIS 5e) coastal marine sands exposed in a cliff section on the coast of southern Jutland (Denmark) are used to test the accuracy and precision of IRSL dating using K-feldspars. This material has been used previously to test quartz OSL dating (): a small systematic underestimation of <10% compared to the expected age of ∼130 ka was reported. In our study, a single-aliquot regenerative-dose (SAR) IRSL protocol is used to determine values of equivalent dose (D) and the corresponding fading rates ( g values). A significant age underestimation (of up to ∼35%) is observed; this is attributed to anomalous fading. Using a single site-average fading rate of 3.66 ± 0.09%/decade to correct the IRSL ages for all samples provides good agreement between the average fading-corrected K-feldspar age (119 ± 6 ka) and the independent age control (132-125 ka). This is despite the reservations of that their fading correction method is not expected to work on samples older than ∼20-50 ka. This fading-corrected feldspar result is not significantly different from the overall revised quartz age (114 ± 7 ka) also presented here. We conclude that fading-corrected IRSL ages measured using K-feldspar may be both precise and accurate over a greater age range than might be otherwise expected. [ABSTRACT FROM AUTHOR]

Ross, M., Lajeunesse, P. & Kosar, K. G. A. 2010: The subglacial record of northern Hudson Bay: insights into the Hudson Strait Ice Stream catchment. Boreas, 10.1111/j.1502-3885.2010.00176.x. ISSN 0300-9483. In this paper, we present new insights into the glacial dynamics and potential configuration of the Hudson Strait Ice Stream catchment in the northern Hudson Bay-western Hudson Strait region. Our reconstruction is based on new field observations and till compositional data from Southampton Island, remote sensing imagery and multibeam bathymetric data from the Hudson Bay sea floor, as well as on a re-examination of previously published data from this vast region. Our findings suggest that, during the late Quaternary, the HSIS catchment consisted of a number of ice-stream tributaries feeding a curvilinear trunk that potentially extended into western Hudson Bay. In contrast to previous interpretations, the occurrence of fluted bedrock hills, over-deepened basins, Dubawnt erratics and carbonaceous till on the islands at the head of Hudson Strait is taken to imply that cold-based conditions did not prevail on these islands. The upland area of Southampton Island and the surrounding channels played an important role in controlling the location of the main tributaries, with the higher central terrain forming a large inter-ice-stream zone lacking carbonate detritus. Coats Island contains abundant evidence of vigorous ice flow, such as mega-scale glacial lineations (MSGLs). MSGLs also occur on the sea floor southwest of Coats Island but the sea-floor imprint is highly discontinuous. Observations on the western Hudson Bay mainland show evidence of southeastward fast ice flow that is spatially consistent with the Dubawnt dispersal train. Despite the geomorphological discontinuities, this may indicate that the HSIS onset zone extended far inside the Laurentide Ice Sheet and across contrasting geological domains. [ABSTRACT FROM AUTHOR]

Zhang, J., Lu, H., Wu, N., Li, F., Yang, X., Wang, W., Ma, M. & Zhang, X. 2010: Phytolith evidence for rice cultivation and spread in Mid-Late Neolithic archaeological sites in central North China. Boreas, Vol. 39, pp. 592–602. 10.1111/j.1502-3885.2010.00145.x. ISSN 0300-9483. The history of rice ( Oryza sativa) cultivation in North China is ambiguous owing to a lack of evidence from rice remains with precise ages in archaeological sites. In this paper, we present rice phytolith evidence from six archaeological sites in the Guanzhong Basin, central North China, dating from c. 5500 to 2100 cal. a BP (calibrated/calendar ages) based on 19 AMS-dates. The phytoliths found in the three archaeological sites located on the second river terrace (Quanhu, Yangguanzhai and Anban) include three types of phytoliths from rice, namely bulliform, parallel-bilobe and double-peaked. These findings suggest that the earliest cultivated rice in central North China occurred not later than c. 5690 cal. a BP. After c. 5500 cal. a BP, the farming pattern in the Guanzhong Basin was characterized by dominant dry crops (e.g. millets) and locally cultivated rice. A likely spread route of rice from the lower reaches of the Huanghe (Yellow) River towards the Guanzhong Basin in central North China is speculated to have happened at c. 5690 cal. a BP. The findings of this study help us to understand the farming pattern in the area and how rice spread across the semi-arid regions of East Asia. [ABSTRACT FROM AUTHOR]

Livingstone, S. J., Ó Cofaigh, C., Evans, D. J. A. & Palmer, A. 2010: Sedimentary evidence for a major glacial oscillation and proglacial lake formation in the Solway Lowlands (Cumbria, UK) during Late Devensian deglaciation. Boreas, Vol. 39, pp. 505–527. 10.1111/j.1502-3885.2010.00149.x. ISSN 0300-9483. This paper is a sedimentological investigation of Late Devensian glacial deposits from the Solway Lowlands, northwest England, in the central sector of the last British–Irish Ice Sheet. In this region, laminated glaciolacustrine sediments occur, sandwiched between diamictons interpreted as subglacial tills. At one location the laminated sediments are interpreted as varves, and indicate the former presence of a proglacial lake. Correlation of these varves with other laminated sediments indicates that the glacial lake was at least 140 km2 in area and probably much larger. Extensive beds of sand, silt and gravel throughout the Solway Basin associated with the lake demonstrate ice-free conditions over a large area. Based on the number of varves, the lake was in existence for at least 261 years. The stratigraphic sequence of varves bracketed by tills implies a major glacial oscillation prior to the Scottish Re-advance (16.8 cal. ka BP). This oscillation is tentatively correlated with the Gosforth oscillation at c.19.5 cal. ka BP. Subsequent overriding of these glaciolacustrine sediments during a westward-moving re-advance demonstrates rapid ice loss and then gain within the Solway Lowlands from ice-dispersal centres in the Lake District, Pennines and Southern Uplands. It is speculated that the existence of this and other lakes along the northeastern edge of the Irish Sea Basin would have influenced ice-sheet dynamics. [ABSTRACT FROM AUTHOR]

Pasanen, A., Lunkka, J. P. & Putkinen, N. 2009: Reconstruction of the White Sea Basin during the late Younger Dryas. Boreas, 10.1111/j.1502-3885.2009.00128.x. ISSN 0300-9483 The Weichselian Scandinavian Ice Sheet (SIS) in the White Sea Basin retreated from its maximum position to the Kalevala end moraine between 17 000 and 11 500 years ago. Even though the deglaciation history is relatively well known, the palaeoenvironments in front of the ice sheet are still poorly understood and partly controversial. In the present paper, we use geomorphological, sedimentological and ground-penetrating radar survey methods to study glaciofluvial plains and shorelines at the Kalevala end moraine. These data are used to define the shoreline gradient for the area and to numerically reconstruct the palaeotopography and the area and volume of the water body in the White Sea Basin during the late Younger Dryas 11 500 years ago. The results indicate that at three sites glaciofluvial plains represent Gilbert deltas deposited to the same water level next to the ice margin. Using the shoreline gradient of 0.42 m/km, it is shown that the water body in the White Sea Basin was extensive and relatively deep, inundating large, currently onshore, areas on the western side of the White Sea and the Arkhangelsk area to the east. The ice margin terminated in the White Sea, which was connected to the Barents Sea via the Gorlo Strait and separated from the Baltic drainage basin to the south. [ABSTRACT FROM AUTHOR]

Anjar, J., Larsen, N. K., Björck, S., Adrielsson, L. & Filipsson, H. L. 2010: MIS 3 marine and lacustrine sediments at Kriegers Flak, southwestern Baltic Sea. Boreas, 10.1111/j.1502-3885.2010.00139.x. ISSN 0300-9483. 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. [ABSTRACT FROM AUTHOR]

This paper describes a Geographical Information System (GIS)-based palaeogeographic reconstruction of the development of proglacial lakes formed during deglaciation in Estonia, and examines their common features and relations with the Baltic Ice Lake. Ice marginal positions, interpolated proglacial lake water levels and a digital terrain model were used to reconstruct the spatial distribution and bathymetry of the proglacial lakes. Our results suggest that the proglacial lakes formed a bay of the Baltic Ice Lake after the halt at the Pandivere-Neva ice margin about 13.3 cal. kyr BP. Shoreline reconstruction suggests that two major proglacial lake systems, one in eastern and the other in western Estonia, were connected via a strait and thus had identical water levels. The water budget calculations show that the strait was able to transfer a water volume several times greater than the melting glacier could produce. As this strait compensated for the water level difference between the two lake parts, the subsequent further merging in north Estonia did not result in catastrophic drainage, as has been proposed. [ABSTRACT FROM AUTHOR]

The Mount Cook area in the Southern Alps of New Zealand is heavily glacierized with numerous peaks over 3000 m a.s.l. feeding several large valley glaciers. The region is subject to rapid tectonic uplift and heavy precipitation (up to 15 m per year). This paper describes the clast roundness, clast shape and textural characteristics associated with five glaciers (Fox, Franz Josef, Hooker, Mueller and Tasman) in terms of inputs to the glacier system, transport by the glaciers and reworking following glacial deposition. Inputs include rockfall, alluvial fan and avalanche material delivered to the surface of valley glaciers. Basal debris, where observed at the terminus of two glaciers, consists mainly of incorporated fluvial material. Following deposition, reworking is mainly by subglacial and proglacial streams. The dominant facies are (i) boulder gravel with mainly angular clasts on the steep slopes above the glaciers, (ii) sandy boulder gravel, with mainly angular and subangular clasts, forming lateral and end moraines, and (iii) sandy boulder/cobble gravel with mainly subrounded clasts, and sand, which represent glacially transported sediment reworked by braided rivers. Diamicton is rare in the contemporary glacial environment. Since most sediment associated with glaciers in the Southern Alps lacks unambiguous indications of glacial transport, interpretation of similar sediments in the geological record should not necessarily exclude the involvement of glacial processes. [ABSTRACT FROM AUTHOR]

This paper describes the internal architecture of a push moraine formed by a winter-spring surge of Hagafellsjökull-Eystri (Iceland) in 1998/99. The sedimentary architecture of this push moraine consists of a multilayered slab of glaciofluvial sediments with a monoclinal structure that has been displaced laterally by the advancing ice margin. The crest and ice-distal face of the moraine consist of subhorizontal sediment sheets, while the ice-proximal face dips steeply (45??to 90?) towards the ice margin. The core of the moraine consists of frozen sediment and thin slabs of glacier ice are embedded in its proximal face. The sediment slabs are characterized by both brittle and ductile styles of deformation. We argue that the observed variation in deformation style is dependent on whether the glacial foreland was frozen or unfrozen at the time of displacement. Frozen foreland would behave in a brittle fashion, while unfrozen foreland is likely to have deformed in a more ductile manner. The associated spatial variations in the degree of foreland freezing could be explained by variation in ice-marginal snow cover. We conclude that the thermal regime of the foreland, and the timing of the ice advance, is of importance to the style of internal deformation found within ice-marginal push moraines. [ABSTRACT FROM AUTHOR]

It has been suggested that extremely long subglacial bedforms (e.g. attenuated drumlins and mega-scale glacial lineations) record former areas of fast-flowing ice and that bedform elongation ratio is a useful proxy for ice velocity. Despite the availability of much data pertaining to the measurement and analysis of subglacial bedforms, these assumptions have rarely been explicitly addressed in detail. In this paper, we demonstrate that long subglacial bedforms (length:width ratios ≥10:1) are indicative of fast ice flow. Using satellite imagery, we mapped over 8000 lineaments associated with a highly convergent flow pattern near Dubawnt Lake, District of Keewatin, Canada. This flow pattern is unusual in that it displays a large zone of convergence feeding into a main 'trunk' and then diverging towards the inferred ice margin. The 'bottleneck' pattern is taken to record an increase and subsequent decrease in ice velocity and we analysed transverse and longitudinal variations in bedform morphometry. The main trunk of the flow pattern (down-ice of the convergent zone) is characterized by mega-scale glacial lineations of great length (up to 13 km) and high elongation ratios (up to 43:1). The down-ice variations in elongation ratio reflect exactly what we would expect from a terrestrial ice stream whose velocity increases in the onset zone passes through a maximum in the main trunk and slows down as the ice diverges at the terminus. It is suggested that any unifying theory of drumlin formation must be able to account for the association between long subglacial bedforms and fast ice flow, although it is not assumed that fast ice flow always produces attenuated bedforms. A further implication of this work is that many more ice streams may be identified on the basis of attenuated subglacial bedforms, radically altering our views on the flow dynamics of former ice sheets. [ABSTRACT FROM AUTHOR]

This paper relates recent proglacial fluvial channel change at Skaftafellsjökull, southeast Iceland, to glacier margin fluctuations. Observations of the western portion of the proglacial braided sandur were made annually between 1996 and 2000. Between 1996 and 1998, during a period of glacier advance, the proximal proglacial outwash surface at the western end of the glacier margin was characterized by a complex braided channel pattern active over the entire sandur surface. Retreat of the glacier margin since 1998 led to rapid incision, so that by 1999 abandonment of the proximal terrace surface and reorganization of the proglacial fluvial system into a single, entrenched channel had occurred. Further retreat and incision occurred during 1999–2000. These observations demonstrate that glacier retreat at Skaftafellsjökull is accompanied by short-lived rapid incision events and terrace formation, separated by long intervals of relatively minor change rather than progressive incision over long time periods. The margin of Skaftafellsjökull is thought to be particularly sensitive to retreat, as the glacier occupies an overdeepening behind the snout and results in lowering of the river's point of exit from the glacier, necessitating adjustment of the river's long profile. [ABSTRACT FROM AUTHOR]

In this paper we briefly compare previously published data on four lateglacial sediment profiles from lakes Holzmaar and Meerfelder Maar in the Eifel region. Two of these profiles (one from each lake) are varvedated, whereas the other two pollen profiles are on depth scales. In general, the palynological signal in all profiles compares well, proving the regional validity of the individual data sets. There are some discrepancies between Holzmaar and Meerfelder Maar, however, mainly concerning varve dating of major lateglacial features, and these are explained after detailed correlation using a combination of varve dating and palynological signals. The result is a consistent varve-dated biostratigraphy for the Lateglacial in the Eifel region. Moreover, it is demonstrated that a combination of varve chronology and high resolution palynostratigraphy in several lake profiles enables even gaps of a few decades up to a few centuries to be detected, thus providing a valuable tool for precise regional palaeoenvironmental study. This multi-core study on two lakes from the same region demonstrates the likelihood of undetected errors in single-core studies on non-varved sediments. [ABSTRACT FROM AUTHOR]

The laminated sediment of Lake Holzmaar (Germany) has provided a continuous varve chronology for the last 3500 varve years (vy) and beyond that a floating varve chronology back to more than 22 500 vy BP. This chronology in calendar years, in combination with palynology, enables us to determine the timing and the magnitude of Lateglacial and Early Holocene environmental changes on land (from 13 838 to 10 930 vy BP). The palynological diagram has a mean time resolution of 27 vy between samples. This paper establishes for the first time the biozonation for Lake Holzmaar below the Laacher See Tephra. Fifteen pollen subzones grouped in four biozones are defined by cluster analysis. After a period disturbed by microturbidites, only a part of the Bølling is present. Three cold periods have been evidenced by pollen analyses: the Older Dryas (96-vy-long), the Younger Dryas (654-vy-long) and the Rammelbeek phase (237-vy-long). The Allerød (883-vy-long) is bipartite with a first Betula-dominated period followed by a Pinus-dominated one. The Younger Dryas is also bipartite, with first a decrease of winter temperatures along with a change to a more continental climate. It is followed by a drier phase with a second decrease in temperatures, probably this time also affecting summer temperatures. The Preboreal is 702-yr-long. The duration of most phases corresponds to published records, except for that of the Younger Dryas. Cluster and rate-of-change analyses indicate a sharp change in the terrestrial vegetation assemblages that may be caused by a sedimentary hiatus of erosive origin during this cold and dry period. As a result, the chronology of Holzmaar has to be revised most likely below the middle of the Younger Dryas. Comparison with the varve record of Meerfelder Maar, a neighbour maar lake, suggests adding 320 vy below 12 025 vy. [ABSTRACT FROM AUTHOR]