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Installations built on ice, permafrost, or seasonal frozen ground require careful design to avoid melting issues. Therefore, efforts to rebuild McMurdo Station, Antarctica, to improve operational efficiency and consolidate energy resources require knowledge of near-surface geology. Both 200 and 400 MHz ground-penetrating radar (GPR) data were collected in McMurdo during January, October, and November of 2015 to detect the active layer, permafrost, excess ice, fill thickness, solid bedrock depth, and buried utilities or construction and waste debris. Our goal was to ultimately improve surficial geology knowledge from a geotechnical perspective. Radar penetration ranged between approximately 3 and 10 m depth for the 400 and 200 MHz antennas, respectively. Both antennas successfully detect buried utilities and near-surface stratified material to ~ 0.5–3.0 m whereas 200 MHz profiles were more useful for mapping deeper stratified and un-stratified fill over bedrock. Artificially generated excess ice which appears to have been created from runoff, water pooling and refreezing, aspect shading from buildings, and snowpack buried under fill, are prevalent. Results show that McMurdo Station has a complex myriad of ice-rich fill, scoria, fractured volcanic bedrock, permafrost, excess ice, and buried anthropogenically generated debris, each of which must be considered during future construction. [ABSTRACT FROM AUTHOR]

Cheekye Fan is a large paraglacial debris flow fan in southwest British Columbia. It owes its origin to the collapse of Mount Garibaldi, a volcano that erupted in contact with glacier ice near the end of the Pleistocene Epoch. The fan extended across Howe Sound, isolating a freshwater lake upstream of the fan from a fjord downstream of it. Squamish River built a delta into this lake during the Holocene. We use 28 radiocarbon ages to describe the final infilling of the lake and the subsequent evolution of the Squamish River floodplain over the past 3300 years. These events are recorded in fine-grained lacustrine, wetland, river channel, and overbank sediments exposed in the banks of Squamish River over a distance of more than 10 km upstream of the fan. We link these deposits to construction, persistence, and eventual degradation of the dam formed by Cheekye Fan and a smaller inset fan formed by Cheakamus River, into which Cheekye River flows. The coupled Cheekye Fan - Squamish River floodplain system is similar to other low-gradient valley floors upstream of fans such as at Tulare Lake, California, and Alexandra River in the Canadian Rocky Mountains. Future debris flows and landslides in the headwaters of Cheekye River are likely to continue to affect base level on lower Squamish River. We speculate that future aggradation of Cheekye Fan would cause increased flooding and sediment deposition upstream of this barrier. These landscape linkages should be included in future land-use planning in lower Squamish River valley. [ABSTRACT FROM AUTHOR]

Abstract: Frozen islands in the Lena River, Siberia, experience rates of fluvial thermal erosion exceeding 10m/year. The islands erode differentially, with rates of frontal retreat exceeding those on island sides. We define the erosion ratio (ER) between the front and sides to estimate this differential erosion. A GIS‐based study of 19 islands from 1967 to 2010 indicated average erosion rates of 19.7 and 3.7 m/year for the island heads and sides, respectively. The average ER over the period was 4.7. An analytical model of local thermal erosion for a frozen cylinder of sand in a turbulent water flow is proposed, assuming an ablation process. Thermal erosion of 19 frozen cylinders was measured for water flows of different temperature and velocity in a cold chamber. As observed in the field, frontal erosion always exceeded lateral erosion, with an average ER of 1.6. The ER decreased with increasing temperature from 5 to 15°C. The higher value of ER in the field may be due to interactions with neighboring islands and banks. An empirical law including phase change and the process of erosion is proposed, and validates our model compared with previous laws that do not account for erosion. The erosion process enhances heat transfer. [ABSTRACT FROM AUTHOR]

Abstract: Patterned ground is a characteristic periglacial landform in polar and alpine environments but has not been systematically studied in karst caves. Here we characterize the periglacial environment and sorted stripes within the Ledenica pod Hrušico ice cave, western Slovenia. The stripes were mapped, sediment depth and grain size were measured, and cave and outside air temperatures were monitored together with ground temperatures. Eleven sorted stripes of coarse limestone debris had developed on 1 m thick silt‐rich sediment, underlain by limestone bedrock. Silt‐rich cave sediments can accumulate as insoluble carbonate residue or during flood events, whereas coarse debris may result from frost shattering. Cold winter air entered the ice cave, but little air exchange occurred during summer, when the cave air temperature slowly rose to a maximum of 5°C. Winter temperature oscillations propagated efficiently to the snow‐free cave floor. Fourteen freeze‐thaw cycles were observed at the patterned‐ground surface during winter 2015/2016 and may cause the differential frost heaving necessary for sediment sorting. Such periglacial conditions and mixtures of silty and coarse sediments can produce sorted patterns in karst caves. [ABSTRACT FROM AUTHOR]

Abstract: In the Swiss Alps, climatic changes have not only caused glacier retreat, but also likely increased sedimentation downstream of glaciers. This material either originates from below the glacier or from periglacial environments, which are exposed as glaciers retreat, and often consist of easily erodible sediment. Griesgletscher's catchment in the Swiss Alps was examined to quantify erosion in the proglacial area, possible hydrological drivers and contributions of the sub‐ and periglacial sources. Digital elevation models, created from annual aerial photographs, were subtracted to determine annual volume changes in the proglacial area from 1986 to 2014. These data show a strong increase in proglacial erosion in the decade prior to 2012, coincident with increasing proglacial area size. However, examination of the gradient between discharge and sediment evacuation, and modeled sediment transport, could suggest that the proglacial area began to stabilize and sediment supply is limited. The large influx of sediment into the proglacial reservoir, which is roughly 2.5 times greater than the amount of sediment eroded from the proglacial area, demonstrates the importance of subglacial erosion to the catchment's sediment budget. Although far more sediment originates subglacially, erosion rates in the proglacial area are over 50 times greater than the rest of the catchment. In turn, both sub‐ and periglacial processes, in addition to constraining sediment supply, must be considered for assessing future sediment dynamics as glacier area shrinks and proglacial areas grow. ©  2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Solifluction is a widespread periglacial phenomenon. Little is known about present solifluction rates in Austria. The author monitored five solifluction lobes during a four-year period. Annual rates of surface velocity, vertical velocity profiles, depths of movement, and volumetric velocities were quantified using near-surface markers and painted lines. Environmental conditions were assessed using air temperature, soil texture, and ground temperature-derived parameters. The latter were used to estimate the relevance of needle-ice creep, diurnal frost creep, annual frost creep, and gelifluction. The mean surface velocity rates were 3.5-6.1 cm yr-1 (near-surface markers) and 6.2-8.9 cm yr-1 (painted lines), respectively, indicating a high relevance of needle-ice creep. The mean depth of movement was 32.5-40 cm. The mean volumetric velocities were 71-102 cm³ cm-1 yr-1. Solifluction rates at the five sites did not correlate with each other due to site-specific controls. No statistically significant correlations were quantified between solifluction rates and different environmental parameters due to data gaps and short time series, thus highlighting the importance of long-term monitoring. Nevertheless, the results suggest that longer zero curtain periods, longer seasonal ground thawing periods, later start of the seasonal snow cover, more freeze-thaw cycles, and cooler early summer temperatures promote solifluction. [ABSTRACT FROM AUTHOR]

The most important stratified screes of the Iberian Range are found in Sierra de Albarracín. These slope deposits have been traditionally considered, without absolute datings, as having been formed during various Pleistocene cold phases. The aim of this paper is to establish the sedimentological, morphological, chronological, and paleoenvironmental characteristics of these deposits through the study of four profiles recorded in the Calomarde canyon (El Rollo, El Molino, and Royuela) and Toril. The most representative profile is that of El Rollo as it is formed by basal tufa and stratified scree layers separated by paleosoils. Radiocarbon datings obtained from paleosoil samples show that the sequence ranges between the early and middle Holocene. The profiles from El Molino and Royuela, as well as the upper levels of Toril, complete the sequence showing deposits from upper Holocene (Bronze Age and ‘Little Ice Age’). These data show the oscillations during the Holocene between colder phases, represented by the stratified screes, and warmer–wetter phases with soil development and local tufa deposits. This geomorphological and pedological response to the Holocene climatic variability shows its clearest records in the canyons. However, there are almost no Pleistocene accumulations – with the exception of that of Toril (minimum age of <43.5 ka BP). The possibility of relating this succession of Holocene environmental changes to known regional and global climatic stages converts these accumulations into the most important Holocene paleoenvironmental record from the Iberian Ranges and the most complete sequence of Holocene stratified screes from the Mediterranean area. [ABSTRACT FROM AUTHOR]

Stratified periglacial sediments extensively cover the slopes of central European low mountain areas. Periglacial cover beds and loess-like sediments as most abundant strata influence many near-surface processes, forming an important component of the Earth's critical zone. The present study focusses on the analysis of a complex sequence of periglacial slope deposits with multiple intermediate layers and intercalated slope wash sediments in order to determine and date periods of intermediate layer formation. Since luminescence dating often provides inconsistent data for cover beds, there is need to reconsider the numerical dating strategy. This study hence places stronger emphasis on numerical dating of interbedded, sufficiently bleached slope wash sediments. The gained OSL-ages are more reliable and consistent and thus, provide a temporal framework for relative dating of intermediate layer formation cycles. In combination with paleosol relics the numerical ages allowed a chronostratigraphic interpretation of Late Pleistocene paleoenvironmental dynamics and slope evolution. Our findings not only prove multiple phases of intermediate layer formation in the study area during the last glacial period but also enabled the correlation of single intermediate layers with specific time spans, including Early and Middle Weichselian as well as the Late Glacial. Remnants of the Eemian soil in the studied sequence even indicate a Saalian age for the lowermost intermediate layer. The present study shows that luminescence dating of intercalated slope wash deposits instead of cover beds is a promising numerical dating strategy for the chronostratigraphic interpretation of cover bed sequences. The findings further illustrate that complex, fanned out periglacial sediment sequences form despite their scarcity important paleoenvironmental archives for Late Pleistocene periglacial landscape dynamics in central European low mountain areas. [ABSTRACT FROM AUTHOR]

Glaciolacustrine sediments in the Clark Fork River valley at Garden Gulch, near Drummond, Montana, USA record highstand positions of the ice-dammed glacial Lake Missoula and repeated subaerial exposure. During these highstands the lake was at greater than 65% of its recognized maximum capacity. The initial lake transgression deposited a basal sand unit. Subsequent cycles of lake-level fluctuations are recorded by sequences of laminated and cross laminated silt, sand, and clay deformed by periglacial processes during intervening periods of lower lake levels. Optically stimulated luminescence (OSL) dating of quartz sand grains, using single-aliquot regenerative-dose procedures, was carried out on 17 samples. Comparison of infrared stimulated luminescence (IRSL) from K-rich feldspar to OSL from quartz for all the samples suggests that they were well bleached prior to deposition and burial. Ages for the basal sand and overlying glaciolacustrine exposure surfaces are indistinguishable within one standard deviation, and give a weighted mean age of 20.9 ± 1.3 ka (n = 11). Based on sedimentological and stratigraphic analysis we infer that the initial transgression, and at least six cycles of lake-level fluctuation, occurred over time scales of decades to ∼2 ka. Bioturbated sandy slopewash dated at 10.6 ± 0.9 ka and 11.9 ± 1.2 ka unconformably overlies the upper glaciolacustrine deposits. The uppermost sediments, above the glaciolacustrine section, are younger than the Glacier Peak tephra (13.7–13.4 cal ka B.P.), which was deposited across parts of the drained lake basin, but has not been found at Garden Gulch. Our study indicates that glacial Lake Missoula reached >65 percent of maximum capacity by about 20.9 ± 1.3 ka and either partially or completely drained twelve times from this position. Rapid lowering from the lake's highstand position due to ice-dam failure likely led to scour in the downstream portions of the glacial Lake Missoula basin and megafloods in the Channeled Scabland. [ABSTRACT FROM AUTHOR]

Much of France remained unglaciated during the Late Quaternary and was subjected to repeated phases of periglacial activity. Numerous periglacial features have been reported but disentangling the environmental and climatic conditions they formed under, the timing and extent of permafrost and the role of seasonal frost has remained elusive. The primary sandy infillings of relict sand-wedges and composite-wedge pseudomorphs record periglacial activity. As they contain well-bleached quartz-rich aeolian material they are suitable for optically stimulated luminescence dating (OSL). This study aims to reconstruct when wedge activity took place in two regions of France; Northern Aquitaine and in the Loire valley. Results from single-grain OSL measurements identify multiple phases of activity within sand wedges which suggest that wedge activity in France occurred at least 11 times over the last 100 ka. The most widespread events of thermal contraction cracking occurred between ca. 30 and 24 ka (Last Permafrost Maximum) which are concomitant with periods of high sand availability (MIS 2). Although most phases of sand-wedge growth correlate well with known Pleistocene cold periods, the identification of wedge activity during late MIS 5 and the Younger Dryas strongly suggests that these features do not only indicate permafrost but also deep seasonal ground freezing in the context of low winter insolation. These data also suggest that the overall young ages yielded by North-European sand-wedges likely result from poor record of periglacial periods concomitant with low sand availability and/or age averaging inherent with standard luminescence methods. [ABSTRACT FROM AUTHOR]

Alases, which are thermokarst depressions that are occupied by grasslands and lakes, are an important element of the Central Yakutian periglacial landscape. In recent decades, climatic changes in Central Yakutia have resulted in important changes in environmental conditions. We use different remote-sensing instruments (Landsat 8, TerraSAR-X, ENVISAT-RA2, and Jason-2) alongside in situ observations to investigate 1) the spatial distribution and water regime of alas lakes and their relationships with climatic and geomorphologic factors, 2) the relationship of the alas' grassland productivity with the water regime and 3) the potential of alas grasslands for local agriculture. During the 2002–2010 period, the lake water level rose by 1.3 m on average, resulting in lake expansion throughout the region. Since 2011, the lake area decreased and the water level declined by 70 cm on the middle terraces (low ground-ice content), while the wetting trend continued until 2016 at higher elevations. Small thermokarst lakes (< 0.025 km 2 ), which indicate regions of young thermokarst, comprise up to 11% of the total lake area and experience high (30%) seasonal variations. In situ observations of the grassland dynamics show their synchronous cyclic variability with the lake extent and a general increasing trend for their productivity since 1985. Around 50% of these dynamics can be explained by the amount of pre-winter precipitation with a delay of two years. We explain this delay through the buffering effect of watershed soils. The cyclic variability of alas hydro-ecosystems strongly affects the local agriculture, which is based on horse and cattle breeding. We estimate that these alas grasslands can provide enough forage supply for local communities. However, the real alas yield is several times less than the theoretical value because of grassland degradation that is caused by recent thermokarst and waterlogging in the most productive phytocenosis. [ABSTRACT FROM AUTHOR]

Beryllium-10 concentrations in samples of sediment and bedrock from five study sites across the Scottish Highlands trace paraglacial sediment sources and define the nature of glacial erosion for the late Quaternary. Exposure ages derived from 10 Be concentrations in ridge and lower elevation bedrock range from 10 to 33 ka, which suggest that polythermal ice and warm based ice were primarily responsible for producing glacial sediment. Comparisons of 10 Be concentrations between catchment-wide sediment (2.06 ± 0.34 × 10 4 to 11.24 ± 1.54 × 10 4 atoms g −1 SiO 2 ; n = 33), near surface deposits (2.71 ± 0.33 × 10 4 to 3.48 ± 0.49 × 10 4 atoms g −1 SiO 2 ; n = 6), 4-m-thick deep till (0.68 × 10 4 10 Be atoms g −1 SiO 2 ; n = 1), ridge bedrock (8.93 ± 0.47 × 10 4 to 34.05 ± 1.66 × 10 4 atoms g −1 SiO 2; n = 20), and lower elevation polished bedrock (6.74 ± 0.67 × 10 4 to 12.65 ± 0.7 × 10 4 atoms g −1 SiO 2 , n = 5) indicate that most sand fluxing through catchments in the Scottish Highlands is sourced from the remobilization and vertical mixing of near surface deposits. These findings indicate that glaciogenic material continues to dominate paraglacial sediment budgets more than 11 ka after deglaciation. [ABSTRACT FROM AUTHOR]

On 17 October 2015, a landslide of roughly 60 × 10 6 m 3 occurred at the terminus of Tyndall Glacier in Taan Fiord, southeastern Alaska. It caused a tsunami that inundated an area over 20 km 2 , whereas the landslide debris itself deposited within a much smaller area of approximately 2 km 2 . It is a unique event in that the landslide debris was deposited into three very different environments: on the glacier surface, on land, and in the marine waters of the fjord. Part of the debris traversed the width of the fjord and re-emerged onto land, depositing coherent hummocks with preserved source stratigraphy on an alluvial fan and adjacent moraines on the far side of the fjord. Imagery from before the landslide shows that the catastrophic slope failure was preceded by deformation and sliding for at least the two decades since the glacier retreated to its current terminus location, exposing steep and extensively faulted slopes. A small volume of the total slide mass remains within the source area and is topped by striated blocks (> 10 m across) and standing trees that were transported down the slope in intact positions during the landslide. Field work was carried out in the summer of 2016, and by the time this paper was written, almost all of the supraglacial debris was advected into the fjord and half the subaerial hummocks were buried by glacial advance; this rapid change illustrates how highly active sedimentary processes in high-altitude glacial settings can skew any landslide-frequency analyses, and emphasizes the need for timely field investigations of these natural hazards. [ABSTRACT FROM AUTHOR]

Long-standing studies of the fixed late-glacial dune fields of the European Sand Belt (ESB) indicate that its development was driven by the degradation of permafrost and the widespread incision of rivers. Ice-marginal valleys, smaller valleys and limnic sediments are considered to be the main sand sources for dune fields within the ESB. However, the provenance of particular dune fields has not been independently assessed. Hence, discussion on the dynamics of the ESB dune fields has been limited to general statements about the distance and duration of aeolian transport. This problem was addressed through the geomorphological (pattern) analysis of 40 dune fields located within the central ESB. Using the calculated construction times and assumed migration rates, we identified the distances covered by the dune fields and their potential sand sources. The study confirmed that fluvial and fluvioglacial sediments were the main sand sources for the ESB dune fields. Most dune fields were found to have migrated over distances of 5–15 km during their development, confirming the short and local aeolian transport. At the same time, long-distance migration of dunes in areas located far from the Fennoscandinavian Ice Sheet was not ruled out. Results indicate dune migration rates as low as 0.5–3.5 m/yr. comparable to contemporary dune fields in cold regions. The methods used have the potential for use in studies in dune fields of other climatic zones, although the results need further verification based on geochemical studies. • European Sand Belt (ESB) dune fields derived mainly from fluvial and fluvioglacial sediments. • ESB dune fields have mostly migrated 5–15 km from their sand sources. • Long distance (>20 km) migration of dunes within the ESB was rare. • Pattern analysis can be used to indicate potential sand sources for dune fields. [ABSTRACT FROM AUTHOR]

• The chemical weathering intensity in Maritime Antarctica is modeled. • A geophysical survey and lithological characteristics as input data. • Proximal geophysical sensors and terrain attributes are combined for modeling. • Use of leave-one-out-cross-validation method in modeling. • Periglacial processes control the distribution of geophysical variables. The chemical weathering intensity in Antarctica is underestimated. As the chemical weathering intensity increases, hydrological, geochemical and geophysical changes occur in the different environmental spheres and at their interfaces through reactions and energy flows. Thus, once chemical weathering rates are understood and estimated, they can be used to predict and assess changes and trends in different environmental spheres. Few studies on the chemical weathering intensity have been performed in Antarctica. We used radiometric and magnetic properties associated with terrain attributes and the chemical degree of alteration of the igneous rock to model the chemical weathering intensity in Maritime Antarctica by using machine learning. Then, we related the chemical weathering intensity and geophysical variables with periglacial processes. To do this, gamma-spectrometric and magnetic readings were carried out using proximal-field sensors at 91 points located on different lithologies in a representative area of Maritime Antarctica. A qualitative analysis of chemical alteration for the different lithologies was carried out based on field observations and rock properties, and the levels of the chemical weathering degree were established. The geophysical data associated with terrain attributes were used as input data in the modeling of the weathering intensity. Then, the levels of the rock weathering degree were used as the "y" variable in the models. The results indicated that the C5.0 algorithm had the best performance in predicting the weathering intensity, and the most important variables were eTh, 40K, 40K/eTh, 40K/eU, the magnetic susceptibility and terrain attributes. The contents of radionuclides and ferrimagnetic minerals in different lithologies, concomitantly with the intensity at which chemical weathering occurs, determine the contents of these elements. However, the stability and distribution of these elements in a cold periglacial environment are controlled by periglacial processes. The chemical weathering intensity prediction model using gamma-spectrometric and magnetic data matched the in situ estimate of the chemical degree of alteration of the rock. The pyritized andesites showed the highest intensities of weathering, followed by tuffites, diorites, andesitic basalts and basaltic andesites, and the lowest weathering intensity was shown by undifferentiated marine sediments. This work highlighted the suitability of using machine learning techniques and proximal-field sensor data to study the chemical weathering process on different rocks in these important and inhospitable areas of the cryosphere system. [ABSTRACT FROM AUTHOR]

The downstream fining of riverbed sediments is ubiquitous; however, this pattern is controlled by multiple factors, including abrasion, sorting, characteristics of sediment sources, water discharge, and river gradient. During the Last Glacial Maximum (LGM), river characteristics (e.g., water discharge, river gradient) differed from those of modern rivers, and the nature of downstream fining in LGM rivers is poorly understood. Due to sea-level fall prior to the LGM, incised valleys formed beneath the present-day coastal lowlands in the Japanese Islands. The bases of these valleys consist of lowstand river sediments (LRSs). Most LRSs in the Japanese Islands are composed of uniform gravel, giving rise to the hypothesis that gravel discharge increased due to periglacial processes in the upper reaches of the rivers during the LGM. In this study, we compiled data on the physical characteristics of 50 Japanese rivers with coastal lowlands at their mouths. From these data, we demonstrate that LRSs span a range of grain sizes from cobble to sand. LRS grain size and thickness decrease downstream, and their maximum observed values are positively linearly correlated with the maximum water discharge, distance from the edge of the continental shelf, and LGM river gradient. These findings suggest that the production of coarse materials was not necessarily a result of periglacial processes, which occurred in a very limited area of the Japanese Islands during the LGM. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation into the processes controlling development of a cryo-conditioned rock coast system in Hornsund, Svalbard. A suite of nested geomorphological and geophysical methods have been applied to characterise the functioning of rock cliffs and shore platforms influenced by lithological control and geomorphic processes driven by polar coast environments. Electrical resistivity tomography (ERT) surveys have been used to investigate permafrost control on rock coast dynamics and reveal the strong interaction with marine processes in High Arctic coastal settings. Schmidt hammer rock tests, demonstrated strong spatial control on the degree of rock weathering (rock strength) along High Arctic rock coasts. Elevation controlled geomorphic zones are identified and linked to distinct processes and mechanisms, transitioning from peak hardness values at the ice foot through the wave and storm dominated scour zones to the lowest values on the cliff tops, where the effects of periglacial weathering dominate. Observations of rock surface change using a traversing micro-erosion meter (TMEM) indicate that significant changes in erosion rates occur at the junction between the shore platform and the cliff toe, where rock erosion is facilitated by frequent wetting and drying and operation of nivation and sea ice processes (formation and melting of snow patches and icefoot complexes). The results are synthesised to propose a new conceptual model of High Arctic rock coast systems, with the aim of contributing towards a unifying concept of cold region landscape evolution and providing direction for future research regarding the state of polar rock coasts. [ABSTRACT FROM AUTHOR]

Climate change will impact the water and sediment conveyance into periglacial reservoirs. It is therefore important to understand and forecast future reservoir sedimentation processes with regard to climate change. In the present project, particle size distribution (PSD) and suspended sediment concentrations (SSC) were measured in three reservoirs in the Swiss Alps whose catchment areas are covered by glaciers by at least 40%. The threefold combination of water sample analysis, laser in-situ scattering and transmissometry (LISST) and acoustic Doppler current profiler (ADCP) was applied and the results were compared to each other. The combination of the three measuring techniques was proven suitable for assessing PSD and SSC in periglacial reservoirs. Water sample analysis and LISST records showed that most of the suspended sediments in the reservoir are in the range of clay and silt. SSC was relatively low in the order of 100 mg/l. An increase in both PSD (e.g. median diameter d50) and SSC with increasing reservoir depth could be observed in deep reservoirs. Flow velocities and Signal-to-Noise ratios (SNR) were measured with ADCP. SNR values allowed to study the mixing of inflowing river water and the evolution and decay of turbidity currents. There is evidence of dominant homopycnal flows, whereas stratified flow was restricted to the regions close to the inflow. Flocculation, influence of mica, and organic content could be neglected. This paper presents detailed information about PSD and SSC gained with water sample analysis and LISST measurements. Furthermore, flow field measurements and tracking of mixing by means of ADCP will be illustrated. Finally, application experiences and limitations will be discussed. [ABSTRACT FROM PUBLISHER]

The Little Ice Age (LIA) is a well-recognized climatic event during which the glaciers in the Alps advanced and reached their maximum Holocene extent. During their retreat following the LIA, the glaciers left large areas of loose or poorly consolidated glacial deposits in their forelands, which are subject to paraglacial reworking and may represent potential hazards for human infrastructures. In this study, we present a regional scale mapping of the LIA and post-LIA glacial deposits and a reconstruction of the maximum LIA extents of glaciers in the same area. This work is motivated by a local law requiring the classification of areas subject to natural hazards in Trentino (Italian Alps). Results highlight that glaciers shrunk by 63% from the LIA maximum, leaving 30 km 2 of unconsolidated deposits, which are subject to geomorphic paraglacial processes. Potentially hazardous consequences can occur, in particular, during high-magnitude instantaneous events, causing debris and mud flows, mass wasting from debris-covered ice, and floods from small moraine-dammed lakes. [ABSTRACT FROM AUTHOR]

In this study, the evolution, the development and the development environment of solution dolines of glaciokarst (the Alps and the Dinarides) are studied. Based on morphological observations (partly with the help of literary data), the dolines of sample sites were put into doline types (giant solution doline, small-sized solution doline and schachtdoline). The various features of the dolines belonging to different doline types were analysed and compared: their size, shape, elongated nature and the slope angle of their side slope. Giant solution dolines are much more similar to the dolines of the temperate belt rather than to small-sized solution dolines or schachtdolines. At temperate climate, giant solution dolines developed under the tree line similarly to dolines of the temperate belt, and not above the tree line. Below the tree line, the dolines grew horizontally to the effect of horizontal dissolution. Later, in the glacials, they developed laterally mainly along their longer axis by glacial erosion. They got into their periglacial environment during the uplifting of the bearing area. In mountains where they are absent, the circumstances of their environment were not present either because the uplifting of the mountain was fast or it was covered by non-karstic rock. The shapes of small-sized solution dolines and schachtdolines prove that their increase happened by deepening. Their deepening was caused by the meltwater of the snow patches of snow drifts which water does not move laterally because of the rock debris of the floor and thus, solution works downwards in the features. Deepening and snow accumulation strengthen each other. These karstic depressions are connected to the periglacial zone because treeless environment favours snow drifts. If the depression is completely filled with snow in most part of the year, the snow patch is wide thus, dissolution affects the total width of the doline. A doline (schachtdoline) with vertical sides and plain floor develops. If snow-fill is only partial in most part of the year, the snow patch and thus, dissolution will have a smaller area and a small-sized solution doline with funnel shape develops. [ABSTRACT FROM AUTHOR]

Beachrock is present in deep, stable sections of a mixed sand and gravel beach at Whitepark Bay (55 o 14′N) on the paraglacial coast of Northern Ireland. The beachrock was revealed following progressive and extreme beach erosion during two particularly stormy winters (2013/14 and 2014/15). It occurs as large (up to 1 m diameter, 0.2 m thick), rounded, disc-shaped concretions in which original beach bedding structures are preserved. Both sand and gravel beach facies are cemented. The cements are similar to those of tropical beachrocks and comprise an initial thin micrite rim, and subsequent grain rims of aragonitic needles. The cementation is attributed to saturation of beach groundwater with calcium carbonate sourced from adjacent Cretaceous chalk outcrop in cliffs behind the beach and dunes. The micrite rims suggest microbial activity in the initial cementation, possibly by scavenging from chalk and skeletal carbonate grains. Subsequent aragonite rims were formed through degassing of CO 2 aided by tidal water level fluctuations. Despite similar cementation processes to low latitude beachrocks, only isolated concretions occur rather than extensive shore-parallel outcrops. Conditions necessary for cementation (and ultimately preservation) in this cold temperate and paraglacial setting include long-term beach stability, a carbonate source (in this case, adjacent chalk cliffs and stream sapping) and tidal water level fluctuations. Bacterial activity may initiate calcite precipitation. Following extreme storms and with progressive shoreline retreat prompted by rising sea levels, increased reporting of cold-water beachrocks is to be expected as formerly stable sections of beaches are exposed to wave action. [ABSTRACT FROM AUTHOR]

In connection with the future Seine-North Europe Canal (Seine-Scheldt), a large-scale rescue archaeological survey was conducted at Havrincourt (northern France) between 2008 and 2011. The discovery of several levels of Palaeolithic flint artefacts embedded in a relatively thick loess sequence (ca 6–7 m) preserved on a gentle slope facing North-East, resulted in a 6000 m 2 excavation. This opened the opportunity for a detailed pedosedimentary and interdisciplinary geochronological survey ( 14 C, optically stimulated luminescence, thermoluminescence, ESR/U-series) that has allowed us date the sequence reliably. On the basis of these results we propose this sequence as a new pedostratigraphic and archaeological reference sequence for northern France. We present here the optical dating of the sequence performed on fine (4–11 μm) quartz grains extracted from 17 samples. The luminescence characteristics of these extracts indicate that the single-aliquot regenerative dose optically stimulated luminescence (SAR-OSL) procedure that was applied is well suited. A consistent set of optical ages was obtained for the loess deposited up to around 70 ka ago. Independent age control (pedostratigraphy, 14 C, ESR/U-series dates) allowed us to apply a Bayesian approach to build a chronometric model. This in turn enabled a regional chronostratigraphic framework to be built, to constrain the correlations with neighboring regions (northern France and Belgium) and to calculate a precise age for the four Palaeolithic levels discovered, including a unique occupation related to the early Upper Palaeolithic which was previously unknown in the area. [ABSTRACT FROM AUTHOR]

A georeferenced database is used to analyse the distribution of Quaternary soft-sediment deformation structures across France. They include features visible in aerial photographs (soil stripes and cells) and features described in cross-section (involutions). Overall, there is no clear relation between the distribution of features and the locations of known faults and earthquakes in available databases. In contrast, the distribution agrees with that of Pleistocene periglacial structures. Most of the soil stripes and cells are located north of 47.5°N, i.e. in the zone of ice-wedge pseudomorphs, and can be interpreted as deformation structures of an active layer in permafrost terrain. The height of the involutions is influenced by the nature of the filling, the substrate and latitude. Deformation structures are larger in coarse material, reflecting the role of drainage and thermal conductivity. Their height increases northward to ca. 2 m at 48°N. This is thought to reflect the increase in thickness of the layer subjected to freeze-thaw cycles. Bowl-shaped structures separated by coarse pillars, which correspond to soil stripes seen in section, have formed on slopes in settings unfavourable to the generation of high pore-water pressure. Their genesis is probably related to differential frost heave. Ball-and-pillow structures and diapirs are common in flat and poorly drained terrain, and formed by liquefaction and sometimes fluidisation in a periglacial setting. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Involutions and small frost fissures have been recorded over a wide area of the lower terrace of the Warta River valley (central Poland). They developed at the lithological boundary between an organic-rich deposit with a thin peat layer (unit b) and an underlying fluvial sandy deposit (unit a). Most of the involutions are products of a reversed density gradient and loading, or developed under the influence of cryohydrostatic pressure. Among them are drop-like and flat-bottomed structures, diapirs, flame-like and fold structures and irregular involutions. Some frost fissures have also been recorded in the same stratigraphic position. The sedimentological properties and formative mechanism of the involutions, together with environmental data (lithology, groundwater conditions, snow cover and vegetation), reveal their origin as periglacial. Radiocarbon dating indicates that the structures formed during the Younger Dryas. Overall, the involutions and frost fissures indicate that permafrost re-aggraded in this region of central Poland during the Younger Dryas. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Intensely cold conditions occurred during part of the last major glaciation of the mountains and Qinghai-Tibet Plateau in northeast China but their chronology is constrained by few limiting ages. At the Mengyuan section, on the northeastern margin of the Qilian Mountains, sandy silt provided three OSL ages that suggest deposition during a very cold, dry period in northeastern China between c. 29 and 19 ka (early part of marine isotope stage (MIS) 2). Load-casting into the underlying outwash gravel occurred during climate amelioration. In some cases, the sandy silt infilled the spaces left by underlying thawing blocks of ice without collapse of the surrounding gravel. The gravel must therefore be older than c. 30 ka and was probably deposited by outwash from glaciers on the higher parts of the Qilian Mountains during MIS 3. Included in them were buried contemporaneous or remnant blocks of glacial ice. Subsequently the surface became flat by unknown processes and was finally covered by a thin loess dating from 2.7 ka, indicating it was deposited in the first warmer period in the Neoglacial sequence of events. Thus, the last major cold event spanned the period through isotope stages 2 and 3 in this area (57 to c. 19 ka), during which the dominant effects of glaciation of the mountain tops were replaced by intensely dry, cold permafrost conditions for c. 10 ka. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Sand grains from Quaternary glacial, aeolian and fluvial deposits in the Mazovian Lowland, central Poland, were examined to characterize the effects of different Quaternary processes on sand-grain surfaces that experienced repeated cycles of intense polar-desert-like conditions during the Middle and Late Pleistocene. A cold, dry and windy periglacial environment prevailed here at least twice between the Saalian (Marine Isotope Stage (MIS) 6) and Holocene (MIS 1) stages. Because the surface characteristics of quartz sand grains can provide important palaeoenvironmental information, we examined grains extracted from sediment samples in different landforms to determine their surficial features from scanning electron microscope images. The grain surfaces were dominated by microtextures characteristic of aeolian-induced grain transformation, indicated by a high percentage of well-rounded, low-relief-worn grains with dish-shaped depressions, bulbous edges and upturned plates. Although remnants of previous sedimentary cycles were occasionally observed, aeolian effects were dominant even in glacial and fluvial settings. Quartz microtextures indicated that none of the examined grains represented their original setting, but rather suggested remobilisation under periglacial conditions. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Sorted circles and polygons are widespread features of periglacial landscapes, but the controls on their development remain poorly understood, impeding their use as palaeoenvironmental indicators. We investigate the relationship of sorted circles and polygons to altitude in the northern Billefjorden area, central Svalbard. The patterns occur in two distinct elevation zones, below 200-250 m asl and above 600 m asl. The higher-elevated patterns have smaller diameters and shallower sorting depths due to a thinner active layer at higher elevations, suggesting that sorted patterns can indicate climate conditions and ground thermal state when the patterns initiated. Geology is believed to be of less importance for pattern morphology in the study area, causing only its fine-scale variations. The pattern diameter-to-sorting depth ratios have a median value of 3.57, consistent with previous studies and theoretical models of patterned-ground formation involving circulation mechanisms. Large-scale sorted patterns may develop over centennial timescales in this high-Arctic environment. They are probably not in equilibrium with present-day climate conditions and have probably formed throughout the Holocene. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

High-elevation ecosystems, such as those on Mount Kenya are undergoing significant changes, with accelerated glacial ice losses over the twentieth century creating new space for alpine plants to establish. These ecosystems respond rapidly to climatic variability and within decades of glacial retreat, Afroalpine pioneering taxa stabilize barren land and facilitate soil development, promoting complex patches of alpine vegetation. Periglacial lake sediment records can be used to examine centennial and millennial scale variations in alpine and montane vegetation compositions. Here we present a 5300-year composite pollen record from an alpine tarn (4370 m asl) in the Hausberg Valley of Mount Kenya. Overall, the record shows little apparent variation in the pollen assemblage through time with abundant montane forest taxa derived and transported from mid elevations, notably high abundances of aerophilous Podocarpus pollen. Afroalpine taxa included Alchemilla, Helichrysum and Dendrosenecio-type, reflecting local vegetation cover. Pollen from the ericaceous zone was present throughout the record and Poaceae percentages were high, similar to other high elevation pollen records from eastern Africa. The Oblong Tarn record pollen assemblage composition and abundances of Podocarpus and Poaceae since the late Holocene (~4000 cal yr BP-present) are similar to pollen records from mid-to-high elevation sites of nearby high mountains such as Mount Elgon and Kilimanjaro. These results suggest a significant amount of uphill pollen transport with only minor apparent variation in local taxa. Slight decreasing trends in alpine and ericaceous taxonomic groups show a long-term response to global late Holocene cooling and a step decrease in rate of change estimated from the pollen assemblages at 3100 cal yr BP in response to regional hydroclimatic variability. Changes in the principal component axis scores of the pollen assemblage were coherent with an independent mid-elevation temperature reconstruction, which supported the strong influence of uphill pollen transport from montane forest vegetation and association between temperatures and montane vegetation dynamics. Pollen accumulation rates showed some variability related to minerogenic sediment input to the lake. The Oblong Tarn pollen record provides an indication of long term vegetation change atop Mount Kenya showing some decreases in local alpine and ericaceous taxa from 5300–3100 cal yr BP and minor centennial-scale variability of montane taxa from mid elevation forests. The record highlights potentials, challenges and opportunities for the use of proglacial lacustrine sediment to examine vegetation change on prominent mountain massifs. [ABSTRACT FROM AUTHOR]

Evidence for mid-high latitude glacial episodes existing within the Late Amazonian history of Mars has been reported from analysis of variety of glacial/periglacial landforms and their stratigraphic relationships. In this study, using the Context Camera (CTX) images, we have surveyed the interior of craters within the Alba Mons region of Mars (30°–60°N; 80°–140°W) to decipher the presence of ice-related flow features. The primary goals of this study are to (1) suggest from observations that the flow features identified in the interior of Alba Mons craters have flow characteristic possibly different from concentric crater fill (CCF) landforms and (2) interpret the extent of glacial activity that led to formation of flow features with respect to previously described mid-latitude ice-related landforms. Our geomorphic investigation revealed evidence for the presence of tongue-like or lobate shaped ice-related flow feature from the interior of ∼346 craters in the study region. The presence of ring-mold crater morphologies and brain-terrain texture preserved on the surface of flow features suggests that they are possibly formed of near-surface ice-rich bodies. We found that these flow features tend to form inside both the smaller (<5 km) and larger (>5 km) diameter craters emplaced at a wide range of elevation (from ∼ −3.3 km to 6.1 km). The measurement of overall length and flow direction of flow features is suggestive that they are similar to pole-facing small-scale lobate debris apron (LDA) formed inside craters. Crater size-frequency distribution of these small-scale LDAs reveals a model age of ∼10–100 Ma. Together with topographic and geomorphic observations, orientation measurements, and distribution within the study region, we suggest that the flow features (identified as pole-facing small-scale LDAs in the interior of craters) have flow characteristic possibly different from CCF landforms. Our observations and findings support the results of previous analyses that suggests Mars to have preserved records of multiple debris-covered glacial episodes occurred in the Late Amazonian. [ABSTRACT FROM AUTHOR]

The periglacial realm is a major part of the cryosphere, covering a quarter of Earth's land surface. Cryogenic land surface processes (LSPs) control landscape development, ecosystem functioning and climate through biogeochemical feedbacks, but their response to contemporary climate change is unclear. Here, by statistically modelling the current and future distributions of four major LSPs unique to periglacial regions at fine scale, we show fundamental changes in the periglacial climate realm are inevitable with future climate change. Even with the most optimistic CO2 emissions scenario (Representative Concentration Pathway (RCP) 2.6) we predict a 72% reduction in the current periglacial climate realm by 2050 in our climatically sensitive northern Europe study area. These impacts are projected to be especially severe in high-latitude continental interiors. We further predict that by the end of the twenty-first century active periglacial LSPs will exist only at high elevations. These results forecast a future tipping point in the operation of cold-region LSP, and predict fundamental landscape-level modifications in ground conditions and related atmospheric feedbacks. [ABSTRACT FROM AUTHOR]

The article discusses the modern periglacial environment of high-latitude and high-altitude regions that extends from the cold limits of forest to the snowline. Within a compact space, several sharply contrasting mountain landscape belts interchange. Living organisms there are particularly affected by cosmic and random-destructive forces. Precisely in these areas, various global geographical, geological, and biological problems are manifested most vividly. The upper limits of agriculture and their importance for high-altitude areas in the main mountain systems of the world are considered. Tourism changes the periglacial environment approach paradigm from the use- and risk-management perspective to the axiological, with attractive categories, angle. [ABSTRACT FROM AUTHOR]

An integrated study of the loess-soil sequence in the coastal exposure near the settlement of Beglitsa (Rostov oblast) allowed us, for the first time, to reconstruct the landscape-climatic changes that occurred in the eastern Azov region over the course of the Late Pleistocene. In the south of the periglacial zone, considerable differences between intensity of the loess accumulation in the Early and Late Valdai Cryochrons were revealed. In the Early Valdai Epoch, which corresponds roughly to the end of Marine Isotope Stage (MIS) 5 and MIS 4, loess accumulation occurred after completion of development of the Mezin pedocomplex and before the beginning of the Bryansk stage of soil development, i.e., over more than 20 000 years. In the much shorter Late Valdai Cryochron MIS 2 (10 000-12 000 years), loess accumulation reached 5 m. The data evaluation shows that the loess accumulation rates in the Early Valdai Epoch (~0.07 mm/year) and the Late Valdai Epoch (~0.5 mm/year) differ from each other by an order of magnitude. [ABSTRACT FROM AUTHOR]

High-resolution aerial images allow detailed analyses of periglacial landforms, which is of particular importance in light of climate change and resulting changes in active layer thickness. The aim of this study is to show possibilities of using UAV-based photography to perform spatial analysis of periglacial landforms on the Demay Point peninsula, King George Island, and hence to supplement previous geomorphological studies of the South Shetland Islands. Photogrammetric flights were performed using a PW-ZOOM fixed-winged unmanned aircraft vehicle. Digital elevation models (DEM) and maps of slope and contour lines were prepared in ESRI ArcGIS 10.3 with the Spatial Analyst extension, and three-dimensional visualizations in ESRI ArcScene 10.3 software. Careful interpretation of orthophoto and DEM, allowed us to vectorize polygons of landforms, such as (i) solifluction landforms (solifluction sheets, tongues, and lobes); (ii) scarps, taluses, and a protalus rampart; (iii) patterned ground (hummocks, sorted circles, stripes, nets and labyrinths, and nonsorted nets and stripes); (iv) coastal landforms (cliffs and beaches); (v) landslides and mud flows; and (vi) stone fields and bedrock outcrops. We conclude that geomorphological studies based on commonly accessible aerial and satellite images can underestimate the spatial extent of periglacial landforms and result in incomplete inventories. The PW-ZOOM UAV is well suited to gather detailed geomorphological data and can be used in spatial analysis of periglacial landforms in the Western Antarctic Peninsula region. [ABSTRACT FROM AUTHOR]

Periglacial processes are active under current climatic conditions on the more exposed peaks and ridges of Tasmania's high country. Non-sorted steps, stripes, and solifluction lobes with vegetated risers and bare treads have formed on many of the mountains capped in fissile sedimentary rocks. Any disturbance to the balance between vegetation and bare ground can result in biogeomorphic feedbacks leading to an increase or decrease in periglacial activity and thereby threaten the survival of fjaeldmark. We tested the hypotheses that vegetation helps create risers by capturing material moved by needle ice, water, and wind, and that the balance between vegetation and bare ground in fjaeldmark is dynamic in Tasmania at the decadal time scale. Repeat photo plots and temperature data loggers were employed to monitor the dynamism of two non-sorted lobes on Mount Rufus over a seven-month period. Diurnal freeze/thaw cycles resulted in needle ice formation on the bare treads and promoted downslope movement of the surface layer through frost creep. Vegetation was observed to reduce geomorphic activity and to capture soil and clasts transported downslope, thereby steepening the risers. Aerial photographic analysis showed a 0.065% per annum increase in vegetation cover in fjaeldmark since the mid-20th century. Mountains that had a high number of days with snow cover were especially prone to increases in vegetation cover. Decline in vegetation cover occurred on some mountains burned during the past century. The smallest changes occurred on the most exposed peaks and ridges. [ABSTRACT FROM AUTHOR]

As a result of complex investigation in the Central Russian Loessal Province, detailed lithologic, geochemical, paleopedological, and paleontological characteristics of the young deposits of the stratotype section Mikhailovka are obtained. They provide the basis for facies genetic differentiation, stratification, and correlation of particular horizons chronologically coordinated by paleopedological and paleontological data with the geological scale of the Neopleistocene. The loess-soil sequences corresponding to climatolites of the Lower, Middle, and Upper Neopleistocene are established and characterized. In dynamical history of the Central Russian Periglacial Loessal Province, thirteen paleogeographical stages of natural-climatic changes (seven warm interglacial and interstadial epochs, six cold epochs alternating with them) are revealed. A rhythmic climatic substantiation for the stratigraphical division of recent sediments in the investigated region is provided. [ABSTRACT FROM AUTHOR]

Ross Mackay's contributions to periglacial geomorphology are commonly regarded as the fruit of solo inspiration. In fact, his work is an exemplary product of its time. At the outset of his career, geomorphology was entering a radical transformation from interpretive study of landscape history towards quantitative study of landscape-forming processes. Early periglacial geomorphology was concerned mainly with attempting to infer historical environmental conditions on the periphery of the great Pleistocene ice sheets and Mackay's earliest works are historically oriented accounts of regional geography. From 1960, however, his work, following the new perspective, was based on quantitative measurement of landforms and land-forming processes, both in the field and on maps, and application of physical theory to interpret his observations. He focused attention on individual periglacial landforms that had hitherto been only superficially described. Outstanding aspects of Mackay's contributions are his genius for making critical field observations and his ability to use them to test geophysical theory. He was one of a very small number of pioneers who reconstructed periglacial geomorphology. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Annual mean ground temperatures ( Tg) decline northward from approximately −3.0°C in the boreal forest to −7.0°C in dwarf-shrub tundra in the Tuktoyuktuk Coastlands and Anderson Plain, NWT, Canada. The latitudinal decrease in Tg from forest to tundra is accompanied by an increase in the range of values measured in the central, tall-shrub tundra zone. Field measurements from 124 sites across this ecotone indicate that in undisturbed terrain Tg may approach 0°C in the forest and −4°C in dwarf-shrub tundra. The greatest range of local variation in Tg (~7°C) was observed in the tall-shrub transition zone. Undisturbed terrain units with relatively high Tg include riparian areas and slopes with drifting snow, saturated soils in polygonal peatlands and areas near lakes. Across the region, the warmest permafrost is associated with disturbances such as thaw slumps, drained lakes, areas burned by wildfires, drilling-mud sumps and roadsides. Soil saturation following terrain subsidence may increase the latent heat content of the active layer, while increases in snow depth decrease the rate of ground heat loss in autumn and winter. Such disturbances increase freezeback duration and reduce the period of conductive ground cooling, resulting in higher Tg and, in some cases, permafrost thaw. The field measurements reported here confirm that minimum Tg values in the uppermost 10 m of permafrost have increased by ~2°C since the 1970s. The widespread occurrence of Tg above −3°C indicates warm permafrost exists in disturbed and undisturbed settings across the transition from forest to tundra. Copyright © 2017 Government of the Northwest Territories. Permafrost and Periglacial Processes © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The climate of northeastern Europe is likely to resemble in many ways Late Pleistocene periglacial conditions in Europe, but there have been relatively few studies exploring the association between climate and morphology in the mid-face of modern northeastern European populations. To fill this gap, we sampled 540 male skulls from 22 European and Near Eastern groups, including 314 skulls from 11 populations from northeastern Europe, to test for possible climate-morphology association at the continental scale. Our results found a moderate and highly significant association (R = 0.48, p = 0.0013, Mantel test) between sets of 23 mid-facial measurements and eight climatic variables. A partial least squares analysis revealed this association to be mostly driven by differences between groups from northeastern Europe and populations from the Mediterranean and the Caucasus. Matrices of between-group genetic distances based on Y-chromosome and mtDNA markers, as well as cranial non-metric and geographic distance matrices, were used to control for the possible influence of shared population history. Irrespective of which measure of neutral between-population distances is taken into account, the association between cranial variables and climate remains significant. The pattern of association between climate and morphology of the mid-face in western Eurasia was then compared to that in east and north Asia. Although differences between the two were found, there were also similarities that support existing functional interpretations of morphology for the bony parts of the upper airways. Last, in a preliminary analysis using a reduced set of measurements, mid-facial morphology of several Upper Paleolithic European Homo sapiens specimens was found to be more similar to groups from northern and northeastern Europe than to southern European populations. Thus, the population of northeastern Europe rather than east and north Asian groups should be used as a model when studying climate-mediated mid-facial morphology of Upper Paleolithic European H . sapiens . [ABSTRACT FROM AUTHOR]

Till macrofabric and grain-size analysis of glacial diamictons and sequences present in several valleys of the Serra do Gerês Mountains in the Northwestern Iberian Peninsula were used to interpret till types and to reconstruct the glacial paleoprocess history of this mountainous region. Subglacial lodgement, supraglacial melt-out, and deformation tills are dominant in this range. Subglacial lodgement tills, representative of periods of glacial advance followed by stability in several valleys, present cluster fabrics and generally poorly sorted and fine sediments. Supraglacial melt-out and deformation tills, representative of periods of glacial stability with some minor readvances followed by recession, present weaker fabric data and coarser, poorly sorted sediments. Glacial deposits affected by post-glacial paraglacial activity in the form of landslides were also observed in one valley. These present weaker to moderate fabric data and coarser, poorly sorted sediments. These glacial diamictons and sequences are of particular importance in the reconstruction of the glacial dynamics and history of the Serra do Gerês Mountains due to poor preservation of glacial landforms related to the Last Glacial Maximum in several glaciated valleys. [ABSTRACT FROM PUBLISHER]

Sierra Nevada constitutes the southernmost and highest massif in the Iberian Peninsula, with elevations exceeding 3000 m. Two large glacial advances were recorded during the Last Glaciation and several minor advances occurred until the Early Holocene. Since then, periglacial activity has prevailed above 2500 m. Here, we present a new and more accurate geomorphological map of the highlands of Sierra Nevada, integrating in a GIS environment i) high resolution satellite imagery, ii) topographic data, and iii) field observations. This approach has allowed a better characterization of the spatial extent of cold-climate morphogenic processes and associated landforms formed during the Last Glaciation and subsequent deglaciation. Despite its extension and high altitude, the steep relief of Sierra Nevada and its southern location conditioned a significantly lower glaciated surface (104.6 km 2 ) with respect to other Iberian massifs. We have also inferred the paleoclimatic conditions of the study area through the calculation of Equilibrium Line Altitudes (ELAs). The distribution of the lowest moraines suggests an ELA for the maximum glacial extent at 2525 m in the northern slope and 2650 m in the southern side, increasing towards the east. Local ELA differences are related to: (i) the influence of the warmer Mediterranean Sea in contrast to the cooler Atlantic Ocean, (ii) the climate with more continental characteristics on the northern slope, and (iii) the microscale control of the local topography. Mean annual air temperatures in the ice-free summit plateaus were between − 4/− 6 °C during the maximum local glacial extent, determining permafrost conditions with intense periglacial dynamics. Rock glaciers and protalus lobes developed until 2500 m, the lowest boundary for permafrost regime. The distribution of other glacial and periglacial landforms within the limits of the maximum ice extent provides evidence to better understand the extent of subsequent glacial stages and post-glacial landscape evolution in Sierra Nevada. [ABSTRACT FROM AUTHOR]

Active rock glaciers are periglacial landforms consisting of coarse debris with interstitial ice or ice-core. Recent studies showed that such landforms are able to support plant and arthropod life and could act as warm-stage refugia for cold-adapted species due to their microclimate features and thermal inertia. However, integrated research comparing active rock glaciers with surrounding landforms to outline their ecological peculiarities is still scarce. We analysed the abiotic (ground surface temperature and humidity, soil physical and chemical parameters) and biotic (plant and arthropod communities) features of two Alpine active rock glaciers with contrasting lithology (silicate and carbonate), and compared them with the surrounding iceless landforms as reference sites (stable slopes and active scree slopes). Our data show remarkable differences between stable slopes and unstable landforms as a whole, while few differences occur between active scree slopes and active rock glaciers: such landforms show similar soil features but different ground surface temperatures (lower on active rock glaciers) and different occurrence of cold-adapted species (more frequent/abundant on active rock glaciers). Both plant and arthropod species distributions depend mainly on the geographical context as a function of soil pH and on the contrast between stable slopes and unstable landforms as a function of the coarse debris fraction and organic matter content, while the few differences between active scree slopes and active rock glaciers can probably be attributed to microclimate. The role of active rock glaciers as potential warm-stage refugia for cold-adapted species is supported by our data; however, at least in the European Alps, their role in this may be less important than that of debris-covered glaciers, which are able to host cold-adapted species even below the climatic tree line. [ABSTRACT FROM AUTHOR]

In glacier forelands, solifluction is a major and fast-responding paraglacial process in the adjustment of low- or moderately-inclined moraine slopes. However, the spatial pattern of the factors that control solifluction and their interactions are poorly understood. In this study, we combine geomorphic and vegetation mapping, analysis of borehole material and time domain reflectometry with two-dimensional (2D) and three-dimensional (3D) electrical resistivity tomography (ERT) to quantify the controlling factors and evaluate their influence on sediment transport. The investigated turf-banked solifluction lobe is located on the distal slope of a 1920s lateral moraine in the foreland of the Turtmann glacier in the southern Swiss Alps. Our data demonstrate the interaction between material, soil moisture and vegetation, which results in geomorphometric features such as (i) frontal and lateral risers, (ii) a lobe tread and (iii) a ridge. Lobe size indicates intense solifluction movement in the last 100 years. The interaction of controlling factors results in a negative feedback which stabilises the lobe and, thus, limits paraglacial sediment transport to frost heave processes on the ridge. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Three maps are presented that portray the periglacial geomorphology of the three summit areas of Bodmin Moor, Cornwall, SW England, including Brown Willy (scale 1:2630), Kilmar/Bearah/Sharp tors (scale 1:3335) and Rough/Little Rough/Showery tors (scale 1:2175). Landform elements include castellated tors with well-developed cantilevered or precariously balanced corestones, summit blockfields, rock-fronted lobes thought to record former permafrost creep, patterned ground (stripes) and lower slope accumulations of crudely stratified growan or weathered granite residue. The altitudinal arrangement of these periglacial landforms appears to be a signature of a well-established periglacial landsystem and hence the Bodmin Moor granite massif is a suitable exemplar for a mature upland periglacial landsystem unaffected by glacierization. [ABSTRACT FROM PUBLISHER]

A 1:19,500 map of the Petunibukta region documents the spatial distribution of almost 300 colluvial and alluvial fans (together with their catchments) in the periglacial high-Arctic environment of Svalbard. Fan-shaped landforms were mapped using an orthophoto and digital elevation model generated from 2009 aerial photographs and a 2013 high-resolution satellite image using Geographic Information Systems. Four additional maps at a scale of 1:40,000 provide details about the morphometric characteristics of the studied fans: long- and cross-profiles, slope and aspect. Additionally, parameters such as fan and catchment area, relief, length, width, elevation (the lowest point at the fan toe, apex, and the highest point of the catchment boundary), fan mean plan and profile curvatures, fan relation to neighbouring fans, are also presented. Fans were classified according to the dominant processes shaping their surface: colluvial fans (n = 229), alluvial fans dominated by debris flows (n = 49), and alluvial fans dominated by fluvial flows (n = 19). [ABSTRACT FROM PUBLISHER]

Meteorological studies have indicated that high alpine environments are strongly affected by climate warming, and periglacial debris flows are frequent in deglaciated regions. The combination of rainfall and air temperature controls the initiation of periglacial debris flows, and the addition of meltwater due to higher air temperatures enhances the complexity of the triggering mechanism compared to that of storm-induced debris flows. On the south-eastern Tibetan Plateau, where temperate glaciers are widely distributed, numerous periglacial debris flows have occurred over the past 100 years, but none occurred in the Tianmo watershed until 2007. In 2007 and 2010, three large-scale debris flows occurred in the Tianmo Valley. In this study, these three debris flow events were chosen to analyse the impacts of the annual meteorological conditions, including the antecedent air temperature and meteorological triggers. The remote sensing images and field measurements of the adjacent glacier suggested that sharp glacier retreats occurred in the 1 to 2 years preceding the events, which coincided with spikes in the mean annual air temperature. Glacial till changes providing enough active sediment driven by a prolonged increase in the air temperature are a prerequisite of periglacial debris flows. Different factors can trigger periglacial debris flows, and they may include high-intensity rainfall, as in the first and third debris flows, or continuous, long-term increases in air temperature, as in the second debris flow event. [ABSTRACT FROM AUTHOR]