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There is a unique glacial landscape system in the southern Żarnowiec Moraine Plateau of northern Poland. Here the terrain is characterized by a very high concentration of ridges that are often adjacent to pits, which together constitutes a special type of hummocky topography. The morphological diversity of the study-area ridges and pits was determined from high-resolution lidar imagery that was qualitatively and quantitatively processed, then analysed. Fourteen test fields of spatial dimensions 0.5 km × 0.5 km were selected within the moraine plateau for detailed studies. The results show that the ridges and pits constitute a very dense network of approximately circular, diverse-oriented forms of various sizes, most of which are linked to each other in a step-wise fashion. The pits are surrounded by ridges of various heights and widths that separate one pit from another. A characteristic feature of the studied pits is the orientation of their long axis. Form-based morphological analysis revealed that their genesis was associated with a glacial rather than a periglacial environment. It is believed that ridge orientation reflects a spatial pattern related to ice crevasses. A moraine plateau constituted a terrain obstacle that acted as a counterslope to the advancing ice sheet. The studied landforms and landscape resulted from the ice sheet's breaking up into dead-ice blocks of various sizes. The very dense system of perpendicular, parallel, and diagonal crevasses was related to ice sheet advance from a northerly direction, resulting in a flow around the obstacle and differences in ice-mass speed. [ABSTRACT FROM AUTHOR]

Proglacial areas in the European Alps and other high-elevation mountains are currently undergoing rapid change due to global warming. Because of rising temperatures, glaciers and glacier forefields are subjected to increased melting and associated sediment export. This observation is increasingly important with respect to high-elevation geomorphological and ecological dynamics, emerging natural hazards and mitigation efforts, and hydropower plant management. It is therefore crucial to analyze the factors and feedback mechanisms governing sediment production, transport, and deposition in these rapidly changing areas. In this study, we investigated the sediment dynamics of a proglacial area located in the Eastern Italian Alps over the period 1969–2021 with the aims of: i) identifying the areas of sediment production; ii) quantifying volumes and rates of bedload sediment transport; and iii) determining the relative contribution of glacial export and fluvial erosion to the total sediment budget. We found that i) apart from glaciers, moraines and fluvial channels have been the most important sediment sources, albeit with substantial differences in terms of connectivity and thus supply rates; ii) the volumes and rates of sediment erosion varied by one order of magnitude (between tens and hundreds of mm per year), and were generally higher along the channel network; and iii) for a relatively shorter time interval between 2005 and 2021, the relative contribution of glacial bedload input with respect to the total sediment budget ranged between 34 % and 37 %, whereas 45 % to 59 % was derived from lateral fluvial erosion. Only a relatively small sediment volume was generated by net channel bed incision. These results imply that most of the sediment released from the proglacial area of the Sulden glacier is progressively transferred to the downstream sector of the channel network, with volumes that range between 931 and 1017 tons yr−1 km−2. These values are in the typical range of sediment export volumes from glaciated basins and highlight the high dynamicity of this region of the Alps. In general, our results confirm the complexity – in terms of spatial and temporal variability – of Alpine proglacial systems and highlight the need to systematically study these areas on a wide spatial and temporal scale, since the information provided by single locations or individual sectors of the sediment cascade, may not be adequate for understanding the dynamics acting in the entire proglacial regions. [Display omitted] • Proglacial areas change rapidly and supply sediment to the downstream valleys. • Moraines and channels are the most important sediment sources. • Glacial and fluvial erosion contribute between 35 % and 50 % to the sediment budget. • The proglacial area of the Sulden glacier is dominated by sediment transport. • In the Sulden region, sediment export may increase in the near future. [ABSTRACT FROM AUTHOR]

The erosional and depositional landforms modified by the glaciers can be used effectively to reconstruct the palaeo-glacial events along with dating techniques. In this study, a detailed reconstruction of the Satopanth Glacier (SPG), Bhagirath Kharak Glacier (BKG), and Bhagnyu Glacier (BG) in the Alaknanda Basin of Central Himalaya is carried out using glacier morphological features identified from a comprehensive dataset that includes historic toposheets (1882–1962), satellite images (1968–2020), and field observations (2019 & 2020). We also compute paleo, contemporary ice thickness, and glacier volumes using the Glacier Reconstructio (GlaRe) and the Himalayan Glacier Thickness Mapper (HIGTHIM) tools, respectively. Our results demonstrate that the region has witnessed three major glacial advances: Stage I (oldest), Stage II, and Stage III glaciations. The SPG, BKG, and BG were tributaries of a primary primitive glacier that existed during the Stage I glaciation that extended to the Mana village. The Stage I glacial moraines are at a distance of 8.4 ± 1.1 km, 7.8 ± 1 km, and 8.4 ± 1.1 km from the present-day snout of SPG, BKG, BG, while the Stage II moraines are 5.1 ± 0.71 km, 4.2 ± 0.58 km, and 5 ± 0.7 km away, and Stage III moraines are 1.9 ± 0.26 km, 1.3 ± 0.18 km, and 2.8 ± 0.39 km away, respectively. The area of the primitive glacier reduced (Stage I to the recent period) from 78 ± 4.6 km2 to 60 ± 3.6 km2 with a volume reduction from 4.7 ± 0.94 km3 to 3.5 ± 0.63 km3. Most importantly, the rate of recession of the glaciers in the Alaknanda Basin is more in the last 5 decades ∼(8.4 ± 1.1 m a−1 (SPG), 7.2 ± 1 m a−1 (BKG), 10 ± 1.4 m a−1 (BG)) than that reported over the last 12,000 years, which is ∼0.42 m a−1 (SPG), 0.35 m a−1 (BKG), 0.42 m a−1 (BG). The present study provides a detailed characterization of the long-term evolution of glaciers in the Alaknanda Basin for the first time. [Display omitted] • Paleoextent of 3 major glaciers in the Alaknanda Basin using satellite and field data • Paleo and contemporary ice thickness estimation using Laminar flow and GlaRe models • Observed 23 % volume and area reduction of glaciers between Stage I and III • Drastic glacier recession, ∼1.3 km to 2.8 km over the last 5 decades • Ice thickness stayed constant, 356–332 m, from Stage I to III. [ABSTRACT FROM AUTHOR]

In order to improve our understanding of the glacier development in central Switzerland after the Last Glacial Maximum (LGM) we have investigated moraine sequences of the Meiental ("Meien Valley"). After detailed field mapping, 34 rock samples from different moraines were dated with cosmogenic 10Be. The results indicate that the investigated moraines were deposited mainly in multi-phased advances during the Younger Dryas and the Early Holocene. This is in contrast to previous studies suggesting that these moraines represent equivalents of the older Egesen and Daun stadials. Our research shows that factors like the moraine stratigraphy, geomorphologic characteristics and Equilibrium Line Altitudes (ELAs) can be highly variable at the local scale, which can make a stadial correlation of moraines between different valleys or regions within the Alps without age constraints ambiguous and unreliable. Against this background the interregional use of ΔELAs (ELA depressions) for the parallelization of paleo-glacier extents throughout the Alps according to traditional concepts of the Lateglacial deglaciation seems to produce erroneous results. Geomorphologic observations and relative age relationships in moraine successions based on stratigraphic principles remain the basis for this kind of studies. But as we show here it is necessary to base local-to-regional comparisons of moraine sequences additionally on exposure ages to gain a more reliable understanding of the Alpine glacier development after the LGM. • Marked multi-phased glacier advances in the Meiental were dated to the YD. • Several Early Holocene moraines prove separate glacier advance/standstill phases. • YD age of supposed Daun equivalent moraines challenges the Daun as separate stadial. • The ELA approach for the parallelization of paleo glaciers has evident limitations. • Exposure dating results increasingly update the concept of the Alpine deglaciation. [ABSTRACT FROM AUTHOR]

Abstract A debris flow occurred in the foreland of Gangotri Glacier by its former tributary, Meru (Bamak) Glacier between 16 and 19 July 2017. We investigated the debris flow using pre- and post-event field observations; hydro-meteorological data along with remote sensing assessments to understand the mechanism and evolution of the debris flow. A large volume of sediments (−7.9 × 106 m3 ± 0.1 × 106 m3) moved from the Meru Bamak and adjoining Neela Taal (4380 m a.s.l) during the debris flow, depositing 6.5 × 106 m3 ± 0.1 × 106 m3 of sediments in the frontal region (4050 m a.s.l) of the Gangotri Glacier. This event transported sediments up to 1.5 km downstream, as a debris flow fan-type feature. During the event, ~18% of the sediments were transferred by the meltwater stream. The stream of the Meru Bamak completely dissected and exposed the ice-cored left lateral moraine of the Gangotri Glacier. This event comprehensively reworked the morainic material and entirely changed the morphology of the pro-glacial area. A small pro-glacial lake (area: 5075 m2) is also observed at the snout of Gangotri Glacier because of the blockage by morainic material and sediments. A sharp increase in the concentration of suspended sediments (SSC), reaching 11,370 and 10,605 mg/l on July 18 and 19, respectively was recorded at Bhojwasa (~3 km downstream). Multiple factors such as recession of Gangotri Glacier, degraded ice-cored moraine, loose sediments at the front of the Meru Bamak, and continuous rainfall created favourable conditions for the debris flow. Therefore, geomorphic hazards associated with glacial retreat need to be investigated intensively in the Himalaya especially, in areas where significant glacial retreat is observed, lateral moraines are exposed, and the unstable slopes are occupied by the tributary glaciers. [ABSTRACT FROM AUTHOR]

Abstract Kuannersuit Glacier in west Greenland experienced a major surge in 1995–1998, where the glacier advanced 10.5 km down-valley. In this paper, we examine how the quiescent phase has progressed until 2015 with respect to ice dynamics, landform formations and glaciomorphological changes. In the initial quiescent phase (2001–2005), ice velocities along the center flowline were 37–55% higher than ice velocities (6.3–9.0 m yr−1) in 2005–2015, and a linear relationship between ice velocity and distance from the glacier front, which existed during the initial quiescent phase, had disappeared in 2005–2015. Between 2001 and 2015, the post-surge glacier tongue thinned by 84.0 ± 6.3 m, equal to 6.0 ± 0.5 m yr−1. The 30-m high terminal moraine detached from the active glacier along the uppermost thrust band between 2005 and 2015, after which the glacier front receded 1.5 km. Between the terminal moraine and the glacier front, observations suggested that a proximal outwash plain was forming on top of glacier ice and that glacier naled (icing, aufeis) was incorporated into the outwash plain. In less dynamic areas with gently sloping topography along the lateral glacier margins, crevasse-squeeze ridges were melting out. The most prominent glaciomorphological feature in 2015 was a c. 1-km long gorge with c. 30–40 m high ice cliffs. This gorge had formed into the glacier front, following the collapse of a series of chasms above the main subglacial channel. Roof collapse processes above subglacial channels had a significant impact on the glacier's mass loss and on the glaciomorphology during the quiescent phase. Earlier observations from 1913 suggest that the formation of this gorge is a reoccurring phenomenon during the quiescent phase. A lower pothole field on the glacier tongue that existed during the initial quiescent phase had completely disappeared in 2015, while a larger upper pothole field in the reservoir area prevailed. During the initial quiescent phase, the subglacial drainage system developed into a stable channelized network, although a jökulhlaup from a large ice-dammed lake occurred. This single event was dated to have occurred between 11 and 13 August 2006, and the lake did not refill. The spatiotemporal association and evolution of glacial and glaciomorphological landforms at Kuannersuit Glacier are likely similar to processes at many other surging and rapidly receding glaciers of similar size. [ABSTRACT FROM AUTHOR]

Small glaciers of temperate mountain regions are suffering significant reduction, with ice mass losses reaching unprecedented melt rates in the very last years. On the other hand, several glacial bodies experienced increasing debris inputs since the end of the Little Ice Age, transitioning from rather clean ice to debris-covered and, sometimes, to rock glaciers. Here we present the recent surface elevation change (2006–2022) of the Popera Alto glacier, a very small debris-covered glacier in the Sesto Dolomites (S-E European Alps), retrieved from a combination of airborne LiDAR and Structure from Motion surveys. We analyse the glacier evolution in terms of surface cover and geomorphic processes, reconstructing its palaeo-volume and -extent from geomorphological evidence. The environmental Equilibrium Line Altitude (envELA) based on climatic data is compared to the effective ELA (effELA), discussing the role of local topography in the evolution of small debris-covered glaciers. Popera Alto glacier lost 0.35 m w.e. yr−1 in the last 16 years, with its surface cover actively modified by geomorphic processes. Debris and local topography feedback allowed the resilience of the glacier, with marked difference between the current envELA of the area, 3480 m a.s.l., and the effELA of the glacier, 2550 m a.s.l. As such, Popera Alto glacier shows evidence of transitioning from a glacial to a periglacial landform. • Debris and local topography feedback extend the survival of small alpine glaciers. • Effective ELA of small glaciers can be hundreds of meters lower than the regional environmental ELA. • Using a single local glacier for climatic reconstruction poses the risk of bias. • Glaciers like Popera Alto are likely to switch into periglacial features soon. • Dynamic debris processes can reshape a glacier surface even in a single year. [ABSTRACT FROM AUTHOR]

Moraine failures are severe events in proglacial areas that lead to major surface changes. On July 1, 2015, a lateral moraine collapsed within the 9.1 km2 glacierized Djankuat Catchment in the Northern Caucasus. This study quantifies the surface changes over a 7-year period after the collapse and proposes the main event triggers using hydrometeorological measurements and remote sensing data. Digital Elevation Models (DEMs), derived from Unmanned Aerial Vehicle (UAV) surveys and satellite images for the 2010–2022 period, were used to estimate erosion/deposition associated with the event and further surface changes in several zones: the breach, the fan, the headward erosion area and gully erosion on lateral moraine slopes. The failure occurred due to an extreme precipitation event (7-day cumulative sum: 227 mm, 24 h prior: 60 mm), simultaneous snowmelt within the whole upstream catchment, and continuous positive temperatures. During the 2015 event, approximately 200,000 m3 of material was instantly eroded, corresponding to a surface lowering of 1.91 m a−1 (over 52,227 m2). Only 25 % of the eroded material redeposited on the fan. Later in 2017–2019, the breach underwent infilling with a 10 m deposition layer in the bottom (net change ca. 14,600 m3), while the stream in the headward erosion area continued to incise (ca. −12,900 m3). From 2019 to 2022, the dynamics decreased, and a positive sediment budget was assessed for all zones except the intensive local erosion on the fan in 2021–2022 (ca. −15,200 m3). Gully changes suggested a constant erosion of 90–100 mm a−1. Based on daily rainfall measurements for the 2008–2022 period, we proposed a 3-day and prior 15-day cumulative precipitation threshold that outlines major erosional events in the Djankuat River valley. A cumulative 3-day precipitation of 100 mm could be a sufficient but not necessary condition since some significant sediment export was recorded below that threshold. • Surface changes due to the moraine failure in the Caucasus were quantified. • The main factors are rainfall, simultaneous snowmelt, and high temperatures. • Deepening caused headward erosion of a new channel, followed by stabilization. • Snowmelt only is not enough to initiate significant erosion. • Erosion-deposition processes occur when the 3-day rainfall exceeds 100 mm. [ABSTRACT FROM AUTHOR]

Abstract An accurate review of the literature on surface exposure dating methods shows evidence of the difficulty in applying cosmogenic dating methods to old moraines because of the intensity of late Quaternary erosion processes. Moreover, as in some previous cases, we also found special difficulties in applying these methods to LIA moraines, caused by the intensity of current paraglacial processes. The objective of this study is to apply cosmogenic dating methods to very old and very young moraines, which in both cases have been or are being affected intensively by erosion. With this purpose, we collected samples of boulders from moraines corresponding to (i) the penultimate glaciation and (ii) the Little Ice Age (LIA), both from Sierra Nevada in the south of the Iberian Peninsula. The sampling strategy was based on a preliminary accurate analysis of the geomorphological settings of two valley sites that resulted in the collection of only four boulder samples from an old moraine and three more from a very recent moraine. Using in situ-produced cosmogenic 10Be to date these boulders, the old samples yielded an age of ca. 130–135 ka for moraine stabilization. The younger samples indicate that the LIA moraine accretion probably occurred between the fourteenth and seventeenth centuries, with a subsequent stage of accumulation during the nineteenth century as suggested by historical documents. Dating a glaciation that occurred prior to the last Pleistocene glacial cycle and dating LIA glacial stages are novel in the context of Iberian glaciations and agree with other palaeoenvironmental studies in Iberian and in other Europe an mountains. The limited number of boulders adequate for cosmic-ray exposure dating prevents statistical methods to be applied, and therefore highlights the need to improve geomorphological criteria in sample selection. Highlights • We examine old and young glaciations in Sierra Nevada (Sothern Spain). • Seven moraine boulders have been CRE dated using 10Be isotope. • The Naute valley includes a moraine of the penultimate glaciation (130–134 ka). • During the LIA a moraine developed in the Veleta cirque (14–17th centuries). • Geomorphological criteria are preferred over dating large number of samples. [ABSTRACT FROM AUTHOR]

The article provides a contribution to the glacial geomorphology of tropical high-altitude mountains. It focuses on the diversity of glacial landforms in the Cordillera Blanca (Peru). The landforms are classified as individual landform types as well as in their hypsometric sequence. Their spatial arrangement is depicted in vertical series and summarised in a glacial-morphological altitudinal belt model. The glacial landforms are analysed in a genetic succession from the moraine-delimited glacier forefields to the excessive pedestal moraines and taking account of the topographical conditions in the verticality. The Pleistocene glacial relief formation is considered as one of the dominating factors in the development of the moraine types. The sediments are on the one hand in situ deposition forms and on the other depositions dislocated by mass movements and represent paraglacial landforms. Using the example of the Paron Valley in the Artesonraju-Huandoy Massif and neighbouring valleys, the article provides a typology of the range of glacial and paraglacial landforms based on a holistic glacial landsystem approach with special reference to pedestal moraines. [ABSTRACT FROM AUTHOR]

Two sets of Pleistocene moraines (Tioga and Tahoe) are preserved at Cascade Lake along the west side of Lake Tahoe. The 10 Be terrestrial cosmogenic nuclide surface exposure ages for two younger Tioga moraines yield an average age of 22.3 ± 1.2 ka, coincident with the global Last Glacial Maximum. The ages suggest that the Tioga glaciation may have reached its maximum several thousand years earlier in the Lake Tahoe basin than to the south along the east flank of the Sierra Nevada. The oldest 10 Be age (120 ± 8 ka) determined for an additional suite of 10 boulders exhibiting significant scatter in 10 Be ages is interpreted to be the minimum age of formation for older Tahoe moraines in the Tahoe basin, suggesting they were deposited during marine oxygen isotope stage 6. The moraines at Cascade Lake are displaced by the West Tahoe Fault that strikes northward for 45 km along the western edge of the Lake Tahoe basin. Vertical displacements of the crests of the Tahoe and Tioga moraines are 59 ± 10 and 32 ± 12 m respectively. Averaged over the time since the formation of the Tahoe and Tioga moraines, the average vertical separation rates are < 0.5 ± 0.1 and ~ 1.4 ± 0.7 mm/y respectively. The measured vertical separation across the broad graben on the Tioga moraine may be accentuated by its deposition on a preexisting scarp and, in this regard, the increase in slip rate since the Tioga glaciation may be apparent rather than real. The fault slip rate and accompanying horizontal rate of extension averaged over the time since the formation of the older Tahoe moraines are respectively 0.6 ± 0.2 and 0.3 ± 0.2 mm/y. The slip rate averaged over the time since emplacement of the Tahoe moraine is in general accord with prior geologic studies reporting slip rate estimates elsewhere along the fault, and the horizontal extension rate is at the lower end of extension rates estimated by others with geodesy across the Tahoe basin. [ABSTRACT FROM AUTHOR]

Erosion processes, aggravated by human activity, have a large impact on the spatial variation of soil and topographic properties. Knowledge of the topography prior to human-induced erosion (paleotopography) in naturally stable landscapes is valuable for identifying vulnerable landscape positions and is required as starting point for erosion modelling exercises. However, developing accurate reconstructions of paleotopography provide a major challenge for geomorphologists. Here, we present a set of paleotopographies for a closed kettle hole catchment in north-east Germany (4 ha), obtained through different reconstruction approaches. Current soil and colluvium thickness, estimated from a dataset of 264 soil descriptions using Ordinary Kriging, were used as input for a mass balance, or were compared with a set of undisturbed soil thicknesses to estimate the amount of erosion. The performance of the different approaches was assessed with cross-validation and the count of mispredicted eroded, depositional or stable landscape positions. The paleotopographic reconstruction approach based on the average thickness of undisturbed soils in the study area showed the best performance. This thickness (1.00 m) is comparable to the average undisturbed soil thickness in the region and in line with global correlations of soil thickness as a function of rainfall and initial CaCO 3 content. The performance of the different approaches depended more on mispredictions of landscape position due to the assumption of a spatially constant initial soil depth than on small variations in this depth. To conclude, we mention several methodological and practical points of attention for future topography reconstruction studies, concerning data quality and availability, spatial configuration of data and other processes affecting topography. [ABSTRACT FROM AUTHOR]

The main relief units from the dry valley of Edson Hills, Ellsworth Mountains, Antarctica (79°49′12.4″/83°40′16.1″), were assessed, emphasizing the analysis of soil and landform interplay. Soil morphological, physical, and chemical properties; salinity; surface boulder weathering (frequency and feature); classification; and weathering stages were analyzed. Three distinct landforms summarize the geomorphology of the dry valley of Edson Hills, Ellsworth Mountains: (i) periglacial features like slightly creeping debris-mantled slopes, steep debris-mantled slopes, patterned grounds, and thermokarst; (ii) glacial features like hummocky moraines, lateral moraines (supraglacial), lakes, kettle hole (proglacial), cirques infill (subglacial), horn, and arête (erosional glacial); and (iii) nonglacial features like scree slopes and talus deposits. All these glacial and periglacial features are related to the West Antarctica ice sheet variations. Soils in the dry valley of Edson Hills are pedologically poorly developed. However, the degree of development in soils associated with patterned ground and moraine systems is remarkable. All soils present desert pavement owing to the action of severe aeolian erosion. In addition, soils accumulate salts depending on the local drainage conditions. The most expressive soil classes among the studied soils were Typic Haploturbel and Typic Anhyorthel, especially because of: (i) a general trend of ice-cemented permafrost occurrence in lower portions of the landscape, particularly in the patterned ground area and in the hummocky moraine; and (ii) the presence of dry permafrost in higher positions of the landscape, in relief units such as in debris-mantled slopes and talus deposits. Thus, a close relationship among soil characteristics and landforms were observed in the dry valley of Edson Hills. [ABSTRACT FROM AUTHOR]

10 Be exposure ages from moraines and bedrock sites in the Roháčská Valley provide chronology of the last glaciation in the largest valley of the Western Tatra Mts., the Western Carpathians. The minimum apparent exposure age of 19.4 ± 2.1 ka obtained for the oldest sampled boulder and the mean age of 18.0 ± 0.8 ka calculated for the terminal moraine indicate that the oldest preserved moraine was probably deposited at the time of the global Last Glacial Maximum (LGM). The age of this moraine coincides with the termination of the maximum glacier expansion in other central European ranges, including the adjacent High Tatra Mts. and the Alps. The equilibrium line altitude (ELA) of the LGM glacier in the Roháčská Valley, estimated at 1400–1410 m a.s.l., was 50–80 m lower than in the eastern part of the range, indicating a positive ELA gradient from west to east among the north-facing glaciers in the Tatra Mts. Lateglacial glacier expansion occurred no later than 13.4 ± 0.5 ka and 11.9 ± 0.5 ka, as indicated by the mean exposure ages calculated for re-advance moraines. This timing is consistent with the exposure age chronology of the last Lateglacial re-advance in the High Tatra Mts., Alps and lower mountain ranges in central Europe. The ELA in the Roháčská Valley estimated at 1690–1770 m a.s.l. in this period was located 130–300 m lower than in the north-facing valleys in the High Tatra Mts. 10 Be exposure ages obtained for a rock glacier constrains the timing of this landform stabilization in the Salatínska Valley and provides the first chronological evidence for the Lateglacial activity of rock glaciers in the Carpathians. [ABSTRACT FROM AUTHOR]

Medial moraines form important pathways for sediment transportation in valley glaciers. Despite the existence of well-defined medial moraines on several glaciers in the New Zealand Southern Alps, medial moraines there have hitherto escaped attention. The evolving morphology and debris content of medial moraines on Franz Josef Glacier and Fox Glacier on the western flank of the Southern Alps is the focus of this study. These temperate maritime glaciers exhibit accumulation zones of multiple basins that feed narrow tongues flowing down steep valleys and terminate ~ 400 m above sea level. The medial moraines at both glaciers become very prominent in the lower ablation zones, where the medial moraines widen, and develop steeper flanks coeval with an increase in relative relief. Medial moraine growth appears somewhat self-limiting in that relief and slope angle increase eventually lead to transport of debris away from the medial moraine by mass-movement-related processes. Despite similarities in overall morphologies, a key contrast in medial moraine formation exists between the two glaciers. At Fox Glacier, the medial moraine consists of angular rockfall-derived debris, folded to varying degrees along flow-parallel axes throughout the tongue. The debris originates above the ELA, coalesces at flow-unit boundaries, and takes a medium/high level transport pathway before subsequently emerging at point-sources aligned with gently dipping fold hinges near the snout. In contrast at Franz Josef Glacier, the medial moraine emerges farther down-glacier immediately below a prominent rock knob. Clasts show a mix of angular to rounded shapes representing high level transport and subglacially transported materials, the latter facies possibly also elevated by supraglacial routing of subglacial meltwater. Our observations confirm that a variety of different debris sources, transport pathways, and structural glaciological processes can interact to form medial moraines within New Zealand's Southern Alps. [ABSTRACT FROM AUTHOR]

Exceptional early high monsoon rains between 15 and 17 June 2013 combined with discharge from snowmelt water caused widespread floods in every major river of the Garhwal Himalaya. This catastrophic event triggered widespread landslides and devastation in the region, affecting the movement of the people that led to stranding of pilgrims in various pilgrimage routes. This event caused many casualties and irreparable damage to the infrastructures and property in the Garhwal Himalaya. A large volume of debris was deposited in Kedarnath town (3.9 x 106 m³), and a huge amount of debris was removed from Rambara and surrounding areas (2.6 x 108 m³). The study also found that villages like Lambaghar, Bhyundar (Alaknanda River Valley), and Rambara (Mandakini River Valley) were completely washed away, leaving no trace of earlier settlement. Govindghat and Pulna villages in the Alaknanda River Valley were also badly damaged. Approximately 0.3 x 106 and 0.72 x 106 m³ of debris was deposited, respectively. Similarly in the Mandakini Valley, Kedarnath and Sonprayag towns were also badly damaged and ~ 3.9 x 106 and ~ 1.4 x 106 m³ of debris was deposited in the area, respectively. Simultaneously, the moraine-dammed Chorabari Lake breached releasing ~ 6.1 x 105 m³ of water with an average rate of ~ 1429 m³/s (discharge of lake). The towns of Pandukeshwar in the Alaknanda Valley and Gaurikund in the Mandakini Valley were partially damaged. However, no evidence of such magnitude of destruction was reported from the Yamuna River Valley during the same period. This catastrophic event changed the landscape in many parts of Uttarakhand, making the whole region more fragile and vulnerable. A disaster of such magnitude was perhaps not witnessed by the region for at least the last 100 years. [ABSTRACT FROM AUTHOR]

The entire Himalayan region is prone to disasters, with many people being vulnerable to hydroclimatic threats such as extreme rainfall-driven floods, glacial lake outburst floods (GLOFs), landslide lake outburst floods (LLOFs), and landslides triggered by rainfall. Landslides and floods are related, as the former cause the lakes that burst, and floods can undercut slopes and cause landslides. During the past 200 years, landslides and floods caused by LLOFs in the Garhwal Himalaya have occurred in 1894, 1970, and 1978; but the most disastrous event, in terms of loss of life and economic impact, occurred in June 2013, which was a result of extreme rainfall in the Higher Himalaya and breaching of a moraine-dammed lake, very short-lived LLOFs, and rainfall-induced runoff and landslides. Outmigration from the area as a result of the 2013 event has caused anxiety about the future of the economy and also concerns about security of a state that has an international border. As a contribution to planning and reconstruction to secure the livelihoods of the local people and to entice migrants to return, this paper identifies zones in the Mandakini valley susceptible to landslides using a 'Weights of Evidence' approach. The roles of climate, geology, and geomorphology of the valley are also given attention to explain the reasons for the disastrous event of June 2013. The results of the research presented here may be an important input to disaster governance. [ABSTRACT FROM AUTHOR]

Deposits near Lamoille in the Ruby Mountains-East Humboldt Range of central Nevada and at Woodfords on the eastern edge of the Sierra Nevada each record two distinct glacial advances. We compare independent assessments of terrestrial cosmogenic nuclide (TCN) surface exposure ages for glacial deposits that we have determined to those obtained by others at the two sites. At each site, TCN ages of boulders on moraines of the younger advance are between 15 and 30 ka and may be associated with marine oxygen isotope stage (MIS) 2. At Woodfords, TCN ages of boulders on the moraine of the older advance are younger than ~ 60 ka and possibly formed during MIS 4, whereas boulders on the correlative outwash surface show ages approaching 140 ka (~ MIS 6). The TCN ages of boulders on older glacial moraine at Woodfords thus appear to severely underestimate the true age of the glacial advance responsible for the deposit. The same is possibly true at Lamoille where clasts sampled from the moraine of the oldest advance have ages ranging between 20 and 40 ka with a single outlier age of ~ 80 ka. The underestimations are attributed to the degradation and denudation of older moraine crests. Noting that boulder ages on the older advances at each site overlap significantly with MIS 2. We speculate that erosion of the older moraines has been episodic, with a pulse of denudation accompanying the inception of MIS 2 glaciation. [ABSTRACT FROM AUTHOR]

Ice-cored lateral–frontal moraines are common at the margins of receding high-Arctic valley glaciers, but the preservation potential of these features within the landform record is unclear. Recent climatic amelioration provides an opportunity to study the morphological evolution of these landforms as they de-ice. This is important because high-Arctic glacial landsystems have been used as analogues for formerly glaciated areas in the mid-latitudes. This study uses SfM (Structure-from-Motion) photogrammetry and a combination of archive aerial and UAV (unmanned aerial vehicle) derived imagery to investigate the degradation of an ice-cored lateral–frontal moraine at Austre Lovénbreen, Svalbard. Across the study area as a whole, over an 11-year period, the average depth of surface lowering was − 1.75 ± 0.89 m. The frontal sections of the moraine showed low or undetectable rates of change. Spatially variable rates of surface lowering are associated with differences in the quantity of buried ice within the structure of the moraine. Morphological change was dominated by surface lowering, with limited field evidence of degradation via back-wastage. This permits the moraine a greater degree of stability than previously observed at other sites in Svalbard. It is unclear whether the end point will be a fully stabilised ice-cored moraine, in equilibrium with its environment, or an ice-free lateral–frontal moraine complex. Controls on geomorphological change (e.g. topography and climate) and the preservation potential of the lateral–frontal moraine are discussed. The methods used by this research also demonstrate the potential value of SfM photogrammetry and unmanned aerial vehicles for monitoring environmental change and are likely to have wider applications in other geoscientific sub-disciplines. [ABSTRACT FROM AUTHOR]

A 200-km-long and 10-km-wide linear assemblage of till-filled geometrical ridges on the bed of the Maskwa palaeo-ice stream of the late Wisconsinan southwest Laurentide Ice Sheet are interpreted as crevasse-squeeze ridges (CSR) developed during internal flow unit reorganization, immediately prior to ice stream shutdown. Ridge orientations are predominantly orientated WNW–ESE, with a subordinate WSW–ENE alignment, both indicative of ice fracture development transverse to former ice stream flow, as indicated by NNE–SSW aligned MSGL. Subglacial till injection into basal and/or full depth, mode I and II crevasses occurred at the approximate centreline of the ice stream, in response to extension and fracturing. Landform preservation indicates that this took place during the final stages of ice streaming, immediately prior to ice stream shutdown. This linear zone of ice fracturing therefore likely represents the narrowing of the fast-flowing trunk, similar to the plug flow identified in some surging valley glaciers. Lateral drag between the final active flow unit and the slower moving ice on either side is likely recorded by the up-ice bending of the CSR limbs. The resulting CSR corridor, here related to an individual ice stream flow unit, constitutes a previously unreported style of crevasse infilling and contrasts with two existing CSR patterns: (1) wide arcuate zones of CSRs related to widespread fracturing within glacier surge lobes; and (2) narrow concentric arcs of CSRs and recessional push moraines related to submarginal till deformation at active temperate glacier lobes. [ABSTRACT FROM AUTHOR]

Understanding the evolution of the ice-bed interface is fundamentally important for gaining insight into the dynamics of ice masses and how subglacial landforms are created. However, the formation of the suite of landforms generated at this boundary — subglacial bedforms — is a contentious issue that is yet to be fully resolved. Bedforms formed in aeolian, fluvial, and marine environments either belong to separate morphological populations or are thought to represent a continuum of forms generated by the same governing processes. For subglacial bedforms, a size and shape continuum has been hypothesised, yet it has not been fully tested. Here we analyse the largest data set of subglacial bedform size and shape measurements ever collated (96,900 bedforms). Our results show that flutes form a distinct population of narrow bedforms. However, no clear distinction was found between drumlins and megascale glacial lineations (MSGLs), which form a continuum of subglacial lineations. A continuum of subglacial ribs also exists, with no clear size or shape distinctions indicating separate populations. Furthermore, an underreported class of bedform with no clear orientation to ice flow (quasi-circular bedforms) overlaps with the ribbed and lineation continua and typically occurs in spatial transition zones between the two, potentially merging these three bedform types into a larger continuum. [ABSTRACT FROM AUTHOR]

Investigating Quaternary glaciations by terrestrial cosmogenic nuclide dating provides unique insights into glacial landscapes. However, postglacial processes may reshape these topographies via weathering, erosion and deposition, especially after the glaciers have entirely disappeared. Understanding the timing of Quaternary glaciations in the areas developed under different geomorphological processes may be challenging. In this study, we produced a detailed geomorphological map of Mt. Barla in the Western Taurus Mountains of Turkey. We found that geomorphological processes such as karstification and mass movements provided favourable settings for the valleys to be carved by glaciers during the Late Pleistocene. We applied in-situ cosmogenic 36Cl surface exposure dating to moraine boulders to reveal the glacial chronology and the geomorphological evolution. We dated moraine boulders (n = 11) from two glacial valleys that show at least two and possibly three deglaciations during the Late Pleistocene. For Gedik Valley, the left lateral moraine marks the LGM glacier retreat by 16.6 ± 2.6 ka (MIS 2). On the other hand, the terminal moraine indicates that the most extensive glaciation occurred at 42.1 ± 5.2 ka (pre-global LGM) in this valley. The outer terminal moraine age (45.5 ± 6.8 ka) in Kapıdere Valley confirms this MIS 3 extension. Our results also imply even a possible earlier glaciation in Kapıdere Valley at 78.5 ± 17.6 ka (MIS 5), even though more data are needed to confirm this extent. • Non-glacial surface processes provided the basis for glacier formations in Mt. Barla. • Multiple glacier advances occurred during the Late Pleistocene. • Using 36Cl cosmogenic exposure dating, we report the oldest glacial event in Turkey. • Lateral moraines imply glaciation during MIS 5 (78.5 ± 17.6 ka). • Lateral moraines indicate final deglaciation during MIS 2 (16.6 ± 2.6 ka). [ABSTRACT FROM AUTHOR]

Geometric characteristics of the washboard moraines of the Des Moines Lobe (DML) of the Laurentide ice sheet agree with their proposed origin as crevasse-squeeze ridges, but study of their sediments is required to help further test this hypothesis. A 70-m-long, 3–5 m high section through a moraine ridge in central Iowa revealed till with irregular, isolated lenses of silt, sand, and gravel that dip to varying extents upglacier. The texture and density of the till are like those of the basal till of the DML studied elsewhere in Iowa, and preconsolidation pressures determined from tests on till and silt of the ridge indicate that it developed subglacially rather than at the glacier margin. Preconsolidation pressures additionally demonstrate that pore-water pressures in the bed supported most of the glacier's weight, which would have contributed to till mobility. Fabrics based on the anisotropy of magnetic susceptibility of 3125 intact till specimens collected at 125 locations in the section indicate two end-member states of strain that varied with location in the ridge and caused sediment mounding: simple shear that was directed downglacier along shear planes inclined upglacier, together with pure shear where an overlying crevasse allowed the sediment bed to extend upward and laterally. Meltwater that likely flowed along the crevasse deposited sorted sediments that were incorporated in till, deformed, and rotated. This positive test of the crevasse-squeeze hypothesis indicates that the DML was in longitudinal extension near its margin, reinforcing previous arguments that the lobe surged. The predominance of fabrics caused by simple shear demonstrates that crevasse filling was underway before the surge had fully halted. This study should prompt caution in using similar transverse ridges, such as those geophysically imaged in some submarine glacier forefields, as indicators of retreat rates. [ABSTRACT FROM AUTHOR]

The Des Moines Lobe (DML)—the largest lobe along the southern margin of the Laurentide ice sheet—deposited low-relief (1–5 m) transverse moraine ridges, herein called washboard moraines, that are most prominent in central Iowa. Their origin as either subglacial or ice-marginal features bears on the dynamics of the lobe, geomorphic reconstructions of it, and interpretations of similar ridges elsewhere. Data from airborne laser swath mapping provide the first digital elevation models with sufficient spatial resolution to study in detail the geometric attributes of these topographically subtle features. Spectral analysis of profiles perpendicular to ridge crests indicates that most of them are spaced with statistically significant periodicities, with dominant wavelengths of 70–150 m. Normalizing and stacking these profiles indicate that, on average, they display no systematic asymmetry. Locally, washboard moraines are intersected by discontinuous longitudinal ridge segments. Trends of the crests of moraines are scalloped, with cusps that point upglacier and are coincident with outwash trains, which were overridden by the lobe. Our interpretation of these data is that the moraines formed subglacially as crevasse-squeeze ridges. Overridden outwash trains likely supported low basal water pressures and resulted in anomalously slow basal slip, causing upglacier deflection of crevasses that extended to the bed. This crevasse-squeeze interpretation reinforces evidence that the DML surged to its maximum position. Bering Glacier, as a temperate, surge-type glacier that deposited crevasse-squeeze ridges similar to the washboard moraines of the DML, may be a good analog for the lobe. [ABSTRACT FROM AUTHOR]

Extensive ice-cored moraine complexes are common elements, marking the last advance of many Svalbard glaciers. Sediment gravity flows are among the most dynamic processes, transforming these landforms. The short-term (yearly and weekly) dynamics of mass-wasting processes were studied in a cm-scale using repetitive topographic scanning. We monitored several active sites on the forelands of two glaciers, Ebbabreen and Ragnarbreen, both of which are located near Petuniabukta at the northern end of Billefjorden in Spitsbergen. The surveys indicate high dynamic rates of landforms' transformation. The mean annual volume loss of sediments and dead-ice for the most active parts of the moraines was up to 1.8 m a − 1 . However, most of the transformation occurred during summer, with the short-term values of mean elevation changes as high as − 104 mm day − 1 . In comparison, the dynamics of the other (i.e. non-active) parts of the ice-cored moraines were much lower, namely, the mean annual lowering (attributed mainly to dead-ice downwasting) was up to 0.3 m a −1 , whereas lowering during summer was up to 8 mm day − 1 . Our results indicate that in the case of the studied glaciers, backwasting was much more effective than downwasting in terms of landscape transformation in the glacier forelands. However, despite the high activity of localised mass movement processes, the overall short-term dynamics of ice-cored moraines for the studied glaciers were relatively low. We suggest that as long as debris cover is sufficiently thick (thicker than the permafrost's active layer depths), the mass movement activity would occur only under specific topographic conditions and/or due to occurrence of external meltwater sources and slope undercutting. In other areas, ice-cored moraines remain a stable landsystem component in a yearly to decadal time-scale. [ABSTRACT FROM AUTHOR]

The Wind River Range spans roughly 200 km along the continental divide in western Wyoming and encompasses at least 269 glaciers and perennial snowfields totaling 34.34 ± 0.13 km 2 (2006), including Gannett Glacier, the largest glacier (2.81 km 2 ) in the continental U.S. outside of Washington State. To track changing glacier and perennial snow surface area over the past century we used historic maps, aerial photography, and geologic evidence evident in said imagery. Since the end of the Little Ice Age (~ 1900), when the glaciers retreated from their moraines, to 2006 the ice-covered area shrank by ~ 47%. The main driver of surface area change was air temperature, with glaciers at lower elevations shrinking faster than those at higher elevations. The total contribution of ice wastage to late summer stream flow ranged from 0.4 to 1.5%, 0.9 to 2.8%, 1.7 to 5.4%, and 3.4 to 10.9% in four different watersheds, none of which exceeded 7% glacier cover. Results from previous studies were difficult to include because of differences in interpretation of glacier boundaries, because of poor imagery, or to extensive seasonal snow. These difficulties highlight potential problems in combining data sets from different studies and underscores the importance of reexamining past observations to ensure consistent interpretation. [ABSTRACT FROM AUTHOR]

Whether glaciers in the southern hemisphere were asynchronous to those in the north during the global Last Glacial Maximum (gLGM; 26.5–19 ka) is still debated. In Patagonia (South America), numerous ice lobes attained their maximum extents during diverse episodes of the last glacial cycle. To understand the variations in the gLGM vs local LGM record, we studied the Lago Aníbal Pinto area (52°00′ S, 72°40′ E; Chile), where several moraine belts were deposited by one of the eastward-flowing southern Patagonian Ice Sheet (PIS) outlet ice lobes; the Última Esperanza. We report eight 10Be terrestrial cosmogenic nuclides (TCN) surface ages from granitic moraine boulders. Our weighted average age obtained from the southern part of the Río Turbio moraine belt yields 50.7 ± 2.4 ka (oldest boulder age; 53.8 ± 5.3 ka) and confirms the greatest extent of the local Last Glacial Maximum (lLGM) during Marine Isotope Stage 3 (MIS 3) in the previously dated northern moraines from the same belt. Our 10Be TCN age (32.6 ± 2.2 ka) derived from the Dos Lagunas moraine, which makes up the northernmost margin of the Última Esperanza ice lobe's Arauco advance, also validates the MIS 3 timing. Following the formation of Arauco moraines, the Última Esperanza ice lobe was split into three main tributaries in the south, which formed three restricted and previously undated moraine complexes. We dated one of them, the Aníbal Pinto moraine complex. Whereas the highest moraine yielded the oldest age (28.3 ± 2.2 ka), lower moraine's surface that was later truncated as a lacustrine erosional platform, yielded younger boulder ages (weighted average age = 18.9 ± 1.0 ka; oldest boulder age = 19.0 ± 1.5 ka), indicating they were deposited under the Pinto Lake level. Our new age data allow us to propose a new chronology for the Aníbal Pinto moraine complex and consolidate previously published ages from other moraine belts. We attribute the Aníbal Pinto moraine complex to early gLGM (MIS 2), emphasising that the gLGM was half the extent of lLGM in the Última Esperanza ice lobe that underpins its interhemispheric asynchronous character. • We present eight 10Be cosmogenic ages from the Última Esperanza (ÚE) ice lobe. • We attribute the Aníbal Pinto moraine complex to the early global LGM (c. 28 ka). • We confirm Río Turbio moraine belt ages (c. 50 ka; MIS 3) in its southern sector. • Global LGM (MIS 2) was half the extent of local LGM (MIS 3) in the ÚE ice lobe. [ABSTRACT FROM AUTHOR]

A glacial geomorphological analysis of three valleys on Mt. Mavrovouni (North Pindus Mountains, Greece) is presented alongside a pilot study using cosmogenic 36Cl to obtain surface exposure ages from iron-rich ophiolite glacial and periglacial boulders. At least three distinct morphostratigraphic units of glacial (moraines) and periglacial (relict pronival ramparts) origin have been identified. Four 36Cl surface exposure ages were obtained from the stratigraphically youngest glacial and periglacial deposits. Although this limited dataset with relatively large uncertainties cannot support a robust geochronology, the ages are consistent with the 36Cl-based chronologies of limestone-derived moraines on Mt. Tymphi (NW Greece) and Mt. Chelmos (S Greece), confirming that the last glaciers on this massif formed during the Last Glacial Maximum as also indicated by other studies in the Pindus mountains. At the same time it provides confidence in the suitability of 36Cl dating for iron-rich samples, such as ophiolites, using an updated 36Cl model that incorporates improved production rates for iron spallation. The presented preliminary chronology of moraines and pronival ramparts is based on those ages as well as on local and regional morphostratigraphic correlations. The stabilisation of the most extensive Late Pleistocene glaciers took place during the Last Glacial Maximum, at 27.0 ± 6.5 ka whereas the presence of pronival ramparts dated at 20.2 ± 4.8 ka suggests persisting cold and arid conditions. Older, still undated glacial deposits exist lower in the valleys which can be attributed to the Middle Pleistocene major glaciation phases (MIS 12/MIS 6), based on their relative morphostratigraphic position within the glacial sedimentary sequence. • Benefits of ophiolite for dating glacial landforms compared with limestone • Pilot study of 36Cl surface exposure dating on ophiolites with high iron content • Preliminary glacial chronology using 36Cl ages and morphostratigraphic correlations • Two distinct glaciations ascribed to the Late and Middle Pleistocene respectively. • Last glaciation on Mt. Mavrovouni in NW Greece occurred around the global LGM. [ABSTRACT FROM AUTHOR]

Ice-marginal moraines are often used to reconstruct the dimensions of former ice masses, which are then used as proxies for palaeoclimate. This approach relies on the assumption that the distribution of moraines in the modern landscape is an accurate reflection of former ice margin positions during climatically controlled periods of ice margin stability. However, the validity of this assumption is open to question, as a number of additional, nonclimatic factors are known to influence moraine distribution. This review considers the role played by topography in this process, with specific focus on moraine formation, preservation, and ease of identification (topoclimatic controls are not considered). Published literature indicates that the importance of topography in regulating moraine distribution varies spatially, temporally, and as a function of the ice mass type responsible for moraine deposition. In particular, in the case of ice sheets and ice caps (> 1000 km 2 ), one potentially important topographic control on where in a landscape moraines are deposited is erosional feedback, whereby subglacial erosion causes ice masses to become less extensive over successive glacial cycles. For the marine-terminating outlets of such ice masses, fjord geometry also exerts a strong control on where moraines are deposited, promoting their deposition in proximity to valley narrowings, bends, bifurcations, where basins are shallow, and/or in the vicinity of topographic bumps. Moraines formed at the margins of ice sheets and ice caps are likely to be large and readily identifiable in the modern landscape. In the case of icefields and valley glaciers (10–1000 km 2 ), erosional feedback may well play some role in regulating where moraines are deposited, but other factors, including variations in accumulation area topography and the propensity for moraines to form at topographic pinning points, are also likely to be important. This is particularly relevant where land-terminating glaciers extend into piedmont zones (unconfined plains, adjacent to mountain ranges) where large and readily identifiable moraines can be deposited. In the case of cirque glaciers (< 10 km 2 ), erosional feedback is less important, but factors such as topographic controls on the accumulation of redistributed snow and ice and the availability of surface debris, regulate glacier dimensions and thereby determine where moraines are deposited. In such cases, moraines are likely to be small and particularly susceptible to post-depositional modification, sometimes making them difficult to identify in the modern landscape. Based on this review, we suggest that, despite often being difficult to identify, quantify, and mitigate, topographic controls on moraine distribution should be explicitly considered when reconstructing the dimensions of palaeoglaciers and that moraines should be judiciously chosen before being used as indirect proxies for palaeoclimate (i.e., palaeoclimatic inferences should only be drawn from moraines when topographic controls on moraine distribution are considered insignificant). [ABSTRACT FROM AUTHOR]

Abstract: Since 1997, the runoff from the High Arctic catchment of Waldemarbreen has been recorded continuously at the gauging station located in northwest Spitsbergen, Svalbard. The analysis of the changes in dynamics and runoff from the glacial (polar) catchment of Waldemarbreen was made. One of the aims of this study was to try to determine how changes in the degree of the glaciation of the catchment influence the volume of the river discharge and runoff. This was found to be directly dependent on the percent glacier cover of the catchment and its changes. Changing the area and the volume of the glacier reduces the rate of the discharge, even when the intensity of melting does not change. Glaciological investigations of Waldemarbreen were taken between 1996 and 2009. The average ablation of Waldemarbreen varied from 64 to 137cm w.e. during this time, while the average winter balance of this glacier was 50cm w.e. During the summer season the mean discharge of the Waldemar River at the point which closed the glacier catchment in the years 1997–2009 was 1.0m3 s−1 (541mm). The average proportion of ablation within the runoff was 55%, and ranged from 30 to 77% during individual seasons. This study also examines selected elements which play some role in the dynamics of the glacial catchment of Waldemarbreen, for example icings or a moraine-dammed lake. It is the first such analysis for this region of Svalbard. [Copyright &y& Elsevier]

Abstract: We use geomorphological analysis, sedimentological survey, remote sensing, and ground penetrating radar (GPR) in order to understand the complex landform assemblage found in front of the Cerro Tapado glacier in the upper Elqui River catchment, semiarid Andes of Chile. The geomorphological analysis highlights prominent boundaries dividing the landform assemblage into (from the upper part to the lower part) an upper latero-frontal moraine complex, an upper debris-covered glacier, a lower debris-covered glacier, two rock glaciers, and a lower morainic complex. The sedimentological survey highlights the rather small size of the surface debris (in general <20cm) and the predominance of porphyritic rhyolite. Remote sensing data show that, between 1956 and 2010, considerable (>400m) receding of the glacier occurred, along with downslope displacements (dm–m·y−1) of most of the landform units and a significant evolution of the thermokarst features on the debris-covered glaciers. Considerable surface lowering occurred in the upper part of the assemblage, while localized bulging is seen along the morphological boundaries in the lower units. The GPR profiles highlight spectacular internal structure in the upper debris-covered glacier with up to 80m of buried ice. In the other landform units, the internal structure is less visible and more heterogeneous. The analysis of the radar wave velocity along the GPR profiles reveals the occurrence of air-filled and moist zones in the internal structure. The geomorphological assemblage is fundamentally characterized by its morphological, structural, and dynamical boundaries and defined as a young (probably <2000years) polygenetic construction with landform units having added to/overlapped one another. The rock glaciers do not derive from the present debris-covered glacier but preexist to it. [Copyright &y& Elsevier]

Abstract: Moraines marking the Neoglacial limits in Svalbard are commonly ice cored. Investigating the nature of this relict ice is important because it can aid our understanding of former glacier dynamics. This paper examines the composition of the lateral–frontal moraine associated with the Neoglacial limit at Austre Lovénbreen and assesses the likely geomorphological evolution. The moraine was investigated using ground-penetrating radar (GPR), with context being provided by structural mapping of the glacier based on an oblique aerial image from 1936 and vertical aerial imagery from 2003. Multiple up-glacier dipping reflectors and syncline structures are found in the GPR surveys. The reflectors are most clearly defined in lateral positions, where the moraine is substantially composed of ice. The frontal area of the moraine is dominantly composed of debris. The core of the lateral part of the moraine is likely to consist of stacked sequences of basal ice that have been deformed by strong longitudinal compression. The long term preservation potential of the ice-dominated lateral moraine is negligible, whereas the preservation of the debris-dominated frontal moraine is high. A glacier surface bulge, identified on the 1936 aerial imagery, provides evidence that Austre Lovénbreen has previously displayed surge activity, although it is highly unlikely to do so in the near future in its current state. This research shows the value of relict buried ice that is preserved in landforms to aiding our understanding of former glacier characteristics. [Copyright &y& Elsevier]

Abstract: In this paper we synthesize the research in glacial geomorphology and geochronology in northern Spain, with special attention to the evidence of local glacier maximum extent earlier than the global LGM of MIS 2 (18–21ka BP). More accurate models of glacier evolution have been defined based on limnogeological, geochronological and geomorphological data. In the Pyrenees, OSL (Optically Stimulated Luminescence), surface exposure and radiocarbon dating techniques have identified end moraines and fluvial terraces corresponding to MIS 6 (about 170ka) and even to MIS 8 (about 260ka), and also established the timing of the last local glacial maxima as prior to global LGM (MIS 4, ca. 50–70ka). During the global LGM a smaller re-advance occurred but glaciers reached different extents in the Central and the Eastern Pyrenees. In NW Iberia, radiocarbon and OSL techniques point to local glacial maximum prior to ca 26ka–38ka and probably synchronous with 45ka. Although some bias might have been introduced by the dating procedures, this review demonstrates that in both regions the local maximum extent occurred prior to the global LGM. The asynchronies between the glacial maxima chronologies in the different mountain ranges of northern Spain suggest that local climate factors exert a strong control on mountain glacier dynamics. [Copyright &y& Elsevier]

Abstract: The last glacial period left a mantle of freshly reworked sediments covering the European landscape. Glacial, periglacial, fluvio-glacial, and aeolian dynamics enhanced transportation and mixing of materials, generating new superficial deposits in which Holocene soils developed. These assorted surface sediments often differed from the underlying bedrock in their lithological composition and texture, and were delimited by lithological discontinuities. In the Swiss Jura Mountains, the Mesozoic limestone bedrocks are covered by various superficial deposits (moraines, cover-beds, loess deposits, cryoclasts, etc.), which reduce or even suppress the influence of limestone on present-day soil development. In this context, soils and their underlying bedrock no longer present a genetic continuity. The nature and relationships between these deposits is studied within a toposequence of soils, in terms of their mineralogical and geochemical compositions. Three main superficial deposits (limestone bedrock clasts, loess, and non-carbonate moraine), are used as reference materials in order to characterize the complex mixing of sediments through the toposequence. Soils with limestone clasts undergo decarbonation and decalcification processes. Iron-rich Alpine loess deposits, composed of fine silicate particles, enhance brunification process in soils. A non-carbonate Alpine moraine displays the most acidic conditions within the toposequence due to enhanced leaching (clay and ions) processes. Consequently, the reworked surface sediments (including limestone cryoclasts, moraines, and cover-beds) have a prevailing influence on pedogenesis compared to the hard underlying bedrock. [Copyright &y& Elsevier]

Abstract: Over many glacial cycles, the glacial erosion of alpine valleys can be sufficient to reduce the length of glaciers in the most recent cycles. We document field cases illustrative of this erosional feedback and model the long-term evolution of glacier lengths analytically and numerically. The general feature we target is a moraine deposited well beyond the last glacial maximum (LGM) limit, which we refer to as a “far-flung” moraine. Firstly, we assemble published observations to illustrate that far-flung moraines are documented around the world. The observations suggest that the downvalley distance to such far-flung moraines can exceed the distance to LGM moraines by up to twofold. Secondly, we address the problem analytically, making several simplifying assumptions, to demonstrate that glacier length scales linearly with erosion depth. Finally, we employ a numerical model to test the analytical solution. This 1D (depth-integrated) flowline model includes: (i) a depth-averaged longitudinal coupling stress approximation, (ii) prescribed winter and summer surface mass balance profiles, (iii) evolving ice temperature calculated via the conventional heat equation, and (iv) glacier sliding velocity parameterized as a function of basal ice temperature and spatially and temporally variable prescribed flotation fraction. The simulated alpine landscape is modified through the competing processes of glacier erosion, which is dependent on glacier sliding velocity and prescribed bedrock erodibility, and prescribed uplift rate. The climate controlling surface mass balance is prescribed by time series of air temperature and snowfall approximated by the sum of two sinusoidal cycles. The recurrence statistics of these prescribed climate drivers closely match those of the marine isotopic record; hence the prescribed climate drivers faithfully mimic observed long-term climate drivers. Consistent with earlier landscape evolution studies, we find that the primary effect of repeated glaciations is to flatten a valley floor and steepen its headwall, effectively cutting a longitudinal notch in a fluvial valley profile. Analytical and numerical model results also demonstrate that far-flung moraines are an inevitable consequence of repeated glaciations: glaciers in tectonically inactive regions can sufficiently erode their valleys so that the earliest glaciations leave moraines many kilometers down-valley from moraines left by the latest glaciations, despite similar climates. This suggests that a different landscape, rather than a different climate, is capable of explaining the early glacier extents. As a corollary, the long-term drift toward reduced glacier length favors the survival of early moraines in the face of later glacial advances. Finally, rock uplift can defeat this erosional feedback, while rock subsidence enhances the feedback. [Copyright &y& Elsevier]

Abstract: Pinar Valley is located on the north side of Galana Peak (40° 15′ 21″ N; 5° 18′ 00″ W; 2564m a.s.l.), Sierra de Gredos, in the center of the Iberian Peninsula. Surface exposure ages based on the in situ accumulation of 36Cl were obtained from six moraine boulders and from three bedrock outcrops to investigate the timing of both the last local glacial maximum and the deglaciation. The oldest moraines, which probably overrode older glacial deposits, are coeval to the global Last Glacial Maximum. Subsequently the Pinar glacier underwent minor pulsations close to its maximum position, followed by general glacier retreat after ~17–16ka. Small cirque glaciers probably remained during the terminal Pleistocene but they had completely disappeared by 10ka. [Copyright &y& Elsevier]

Abstract: In the Obernberg valley, the Eastern Alps, landforms recently interpreted as moraines are re-interpreted as rock avalanche deposits. The catastrophic slope failure involved an initial rock volume of about 45million m³, with a runout of 7.2km over a total vertical distance of 1330m (fahrböschung 10°). 36Cl surface-exposure dating of boulders of the avalanche mass indicates an event age of 8.6±0.6ka. A 14C age of 7785±190calyr BP of a palaeosoil within an alluvial fan downlapping the rock avalanche is consistent with the event age. The distal 2km of the rock-avalanche deposit is characterized by a highly regular array of transverse ridges that were previously interpreted as terminal moraines of Late-Glacial. ‘Jigsaw-puzzle structure’ of gravel to boulder-size clasts in the ridges and a matrix of cataclastic gouge indicate a rock avalanche origin. For a wide altitude range the avalanche deposit is preserved, and the event age of mass-wasting precludes both runout over glacial ice and subsequent glacial overprint. The regularly arrayed transverse ridges thus were formed during freezing of the rock avalanche deposits. [Copyright &y& Elsevier]

Abstract: Moraine-dammed glacial lakes are becoming increasingly common in the Himalaya as a result of glacier mass loss, causing concern about glacier lake outburst flood risk. In addition to extant lakes, the potential exists for many more to form, as more glaciers ablate down to the level of potential moraine dams. In this paper, we document the recent rapid growth of, a moraine-dammed lake on Ngozumpa Glacier, Nepal. Using a combination of ground-based mapping and sonar surveys, aerial photographs (<1m resolution), and ASTER imagery (15m resolution), processes and rates of lake expansion have been determined. The lake first formed between 1984 and 1992 when collapse of an englacial conduit allowed water to accumulate at the level of a gap in the lateral moraine, ~km from the glacier terminus. Lake growth was initially slow, but since 2001 it has undergone exponential growth at an average rate of 10%y−1. In 2009, the lake area was 300,000m2, and its volume was at least 2.2million m3. Calving, subaqueous melting, and melting of subaerial ice faces all contribute to the expansion of the lake; but large-scale, full-height slab calving is now the dominant contributor to growth. Comparison with other lakes in the region indicate that lake growth will likely continue unchecked whilst the spillway remains at its current level and may attain a volume of hundreds of millions of cubic metres within the next few decades. [Copyright &y& Elsevier]

Abstract: We present the results of dating glacial landforms in Venezuela using 10Be terrestrial cosmogenic nuclide (TCN) analysis and optical stimulated luminescence (OSL). Boulders on the La Victoria and Los Zerpa moraines of the Sierra Nevada that mark the extent of the local last glacial maximum (LLGM) yield 10Be TCN surface exposure ages of 16.7±1.4ka (8 samples). About 25km to the west in the drainage basin of the Río Mucujún, 10Be TCN dates for boulders on moraines at La Culata in the Sierra Nevada Norte yield a younger average age of 15.2±0.9ka (8 samples). The data suggest that glaciation across the Venezuelan Andes during the LLGM was asynchronous. The LLGM in Venezuela may be broadly concurrent with Heinrich Event 1 at ~16.8ka, implying that glaciation here is dominantly temperature driven. A moraine inset into the older laterofrontal moraines of La Culata has an age of 14.1±1.0ka (5 samples); it may have been deposited by a small Late Glacial readvance. Right-lateral offsets of the La Victoria and Los Zerpa moraines by the Boconó fault are each ~100m. The 10Be TCN based Boconó fault slip rate is about <~5.5 to 6.5mma−1, notably less than the total right-lateral slip of 12±2mma−1 of shear documented across the Andes from geodesy. The 10Be TCN dating of boulders on a faulted alluvial fan along the northwestern range front at Tucanízón yields a late Pleistocene uplift rate of the Andes at between ~1.7±0.7mma−1. Glacial outwash has produced valley-fill sequences within the central Andean valley along the trace of the Boconó fault and Río Chama. The valley-fill has been incised to produce the ‘meseta’, a terrace surface that sits >100m above the Río Chama and on which the major city of Mérida is built. Geomorphic observations indicate that the meseta deposits were largely derived from the glaciers of La Culata. The OSL dating suggests that the final aggradation of the valley-fill deposits occurred rapidly over a period of about 5 to 6ka and that the surface was abandoned and initially incised at ~30ka. The result implies Venezuelan valley fills record phases of aggradation that are likely modulated by climate change on glacial/Milankovitch timescales. [Copyright &y& Elsevier]

Abstract: Although large rock avalanches are infrequent, sediment production in active orogens is dominated by such events, which may strongly influence geomorphic processes. Where rock avalanches fall onto glaciers, they may affect glacier behaviour and moraine formation. We outline the processes of rock avalanche initiation and motion, and show that supraglacial deposits of rock avalanche debris have distinct sedimentological and thermal properties. Laboratory experiments on the effects of such debris on ice ablation are supplemented by field data from two rock avalanches in the Southern Alps, New Zealand. Their effects are compared with those of the thinner supraglacial debris that results from small rockfalls and melt-out of englacial debris. Implications of rock–avalanche debris cover for glacier behaviour are explored using a mass-balance model of the Franz Josef Glacier in New Zealand, demonstrating a likely supraglacial rock avalanche origin for the Waiho Loop moraine, and considering the potential hazard of a large rock avalanche onto the present-day glacier. [Copyright &y& Elsevier]

Abstract: Late Glacial terrain in the Schwarzensteinkees, Hornkees and Waxeckkees forelands of the Zillertal Alps is dominated by sediments deposited by readvancing ice emplaced in the Little Ice Age, starting approximately 550±70cal 14C yr BP. Late Glacial ice scoured the massif with remnants of Late Glacial end moraines fronting LIA end moraines and buried paleosols underlying LIA end moraines providing scattered evidence of compositional change and weathering since the Later Dryas. The amount of recovered wood from LIA moraines indicates that the massif was forested for at least part of mid-Holocene times, most likely during the Atlantic Chronozone when, presumably, soil morphogenesis was accelerated. Details of till composition and weathering history provide a pedostratigraphic reconstruction which includes mid-LIA readvances between 400±70cal 14C yr BP and 350±70 cal14C yr BP. The heavily convoluted character of underlying early LIA or older tills suggests either pre-existing strongly active cryoturbation in a thin Entisol (Regosol) or active push moraine dynamics of advancing warm ice. SEM analysis documents differences in glacial dynamics that may be related to ice thickness, stick–slip motion or clastic load in the ice coupled with rate of movement. [Copyright &y& Elsevier]

Abstract: Previous studies have interpreted landforms east of Mount Shiroumadake (2932m asl), in the Northern Japanese Alps, as lateral and terminal moraines and outwash terraces of glacial origin. However, recent studies in other areas of the Northern Japanese Alps have interpreted similar landforms as characteristic landslide bodies. We re-examined the origin and age of moraine-like landforms on the eastern side of Mount Shiroumadake through field geological surveys and landform analysis. We show that terminal moraine-like landforms in our study area consist of beds of brecciated or crushed gravel with locally derived crackle clasts and are unrepresentative of the variety of bedrock expose in the plausible source areas of Pleistocene glaciers. We interpret these deposits as induced by mass rock creep and landsliding at the terminus of a steep ridge or a steep valley side slope. Similarly, terrace surfaces formerly-interpreted as of outwash or fluvial origin consist of gravel beds with many fractured rock clasts of landslide origin. Although the timing of the landslides is not well constrained, they may have occurred in the early to middle Holocene. The highly deformed rocks of the study area, combined with the humid climate with much snowfall and rainfall, have left the landscape with an inherent predisposition for landsliding. Paleoearthquakes on nearby active faults in the piedmont area of Mount Shiroumadake may have provided a direct trigger for landsliding. [Copyright &y& Elsevier]

Abstract: Landforms in Val Mulix and the Albula region in eastern Switzerland offer a detailed insight into the period between the Oldest Dryas until the early Holocene. To better understand Lateglacial and Holocene climate change in the central Alps, glacial (moraines, polished bedrock) and periglacial (rock glacier) landforms were dated using a combined approach of numerical (cosmogenic 10Be) and relative (Schmidt-hammer, weathering rind thickness) dating techniques. At high-elevation sites near the Last Glacial Maximum (LGM) trimline, 10Be exposure ages of glacially modified bedrock are between 11.2ka and 13.5ka. This suggests the persistence of long-lasting small local ice caps after the breakdown of the LGM ice domes or, alternatively, a reformation of ice perhaps during the Younger Dryas. In Val Mulix we obtained one of the first ages for the Daun-stadial (>14.7ka) moraines (14.9±1.8ka), supporting a pre-Bølling chronological position. The age is in excellent agreement with the age of a boulder from an Egesen I moraine located up-valley which we postulate may be a Daun moraine that was re-occupied during the Egesen stadial. A boulder from an Egesen II moraine gave an age of 10.7ka, which is similar to ages of Egesen II moraines at other sites in the Alps. 10Be ages from boulders found on a relict rock glacier in Val Mulix indicate that the main active phase lasted from the Lateglacial until the early Holocene. The derived mean annual flow rate is of the order of decimetres, which is in accordance with values stated in the literature based on measuring active rock glaciers in the Alps. Exposure ages from a glacially polished rock barrier showed that this area was ice-free at the end of the Younger Dryas (9.0±0.7ka and 11.9±0.9ka). The polished bedrocks are located a few hundred meters down-valley from the Little Ice Age (LIA) moraines. This gives direct evidence of a fast ice retreat towards the end of the Younger Dryas, with glacier length variations that did not exceed the 1850 AD extension (Little Ice Age maximum). Surface exposure dating is, however, limited by several methodological constraints. The choice of suitable snow depths plays a crucial role in the calculation of the 10Be ages. Shielding of surfaces from cosmic rays by snow can significantly influence the exposure age, and variations in the estimated annual snowfall in the Albula region since the LGM is therefore a potential source of considerable uncertainty in our measurements. While the measurement of weathering rind thicknesses turned out to be an appropriate tool to support the reconstruction of Lateglacial landscape evolution, Schmidt-hammer R-values were less helpful. The R-values enabled a temporal distinction of landforms within the Holocene (LIA moraine, active rock glaciers) but not within the Lateglacial. From a methodological point of view, the different dating methods enabled a cross-checking, an extended interpretation of the data and a more accurate estimate of the possible sources of error. [Copyright &y& Elsevier]

Abstract: Progressive glacier thinning, retreat and mass loss in the High-Arctic is increasingly exposing forefield sediments to processes of mobilisation and redistribution. In this paper, we quantify forefield sediment redistribution at Midtre Lovénbreen, Svalbard, using repeat light detection and ranging (lidar) surveys conducted in 2003 and 2005 in combination with field-based observations. Average surface lowering of the forefield over the observation period identified from lidar surveys is −0.05ma−1; and two primary areas of sediment reworking are identified: active fluvial incision of proglacial streams by ~2m and lateral moraine downwasting of similar magnitude. Multivariate analysis of fluvial and climatological field data indicates that observed forefield sediment mobilisation is driven primarily by discharge forcing, but with contributions from thermoerosive processes and stochastic, autogenic sediment supply. During the period of observation, disparity between sediment loss in forefield fluvial systems as calculated from lidar data (3000–4000×103 kg) and monitoring of fluvial sediment load (1600–3500×103 kg) suggests the likely presence of significant quantities of buried ice beneath a thick debris mantle, as evidenced by field observations. Relatively uniform lowering of the moraine crest identified from our repeat lidar surveys indicates thermoerosion of an ice core. However, simple debris layer thickness modelling indicates an increase in variation of debris layer thickness at lower elevations, providing support for the assertion that moraine disintegration is driven by complex combinations of both thermal and mechanical processes. This study demonstrates the viability of using lidar in conjunction with field monitoring to better understand sedimentary deglaciation dynamics and processes, and also highlights the significance of forefield areas in controlling the sediment yield from deglaciating catchments. [Copyright &y& Elsevier]

Abstract: The subdivision and ordering of Quaternary sediments and landforms is very often based on geomorphology. Quaternary landforms such as moraines, river terraces, palaeoshorelines, and indeed any other landform, can be arranged and ordered in time based on their relative position in the landscape. Morphostratigraphy is the subdivision of sedimentary units primarily on the basis of surface form. Whilst surface form is often used as a criterion for separating sedimentary units, morphostratigraphy also usually incorporates lithological criteria to aid stratigraphical subdivision, and morpho- and lithostratigraphy are often interlinked in Quaternary science. However, another approach–allostratigraphy–has increasingly been applied to subdivide and order Quaternary sediment landforms. Allostratigraphy uses discontinuities to subdivide sedimentary successions. Allostratigraphy enables lateral variations in lithology to be included within the same stratigraphical unit. Furthermore, it enables lithologically similar sediments stacked on top of each other to be divided into separate units based on discontinuities. This paper examines the applications of morpho-, litho- and allostratigraphy to subdivide sediment-landform assemblages and critically reviews their role in Quaternary stratigraphy. [Copyright &y& Elsevier]

Abstract: This study utilizes Landsat TM, ASTER and Synthetic Aperture Radar (SAR)-derived DEMs in conjunction with Geographic Information Systems (GIS) in order to reevaluate previously-published interpretations of glacial landforms in and around Devil''s Lake State Park, south-central Wisconsin, USA. Devil''s Lake sits in a gorge carved into the southern flank of a doubly-plunging syncline known as the Baraboo Hills through which the Wisconsin or some other river flowed prior to the last ice age. During the last glacial maximum about 18,000B.P., an outlet glacier of the Laurentide Ice Sheet called the Green Bay Lobe extended southward into south-central Wisconsin and left behind extensive glacial landforms such as moraines, drumlins and eskers. During advance of the Green Bay Lobe into the region, Devil''s Lake Gorge was plugged at both ends by glacial deposits and resulted in formation of Devil''s Lake. The Wisconsin River, if it originally flowed through Devil''s Lake Gorge, found a new course to the east of the Baraboo Hills Syncline. This study utilizes the aforementioned remote sensing data to spatially image the following features: (1) Original extent of the Green Bay Lobe, (2) Moraines and streamlined glacial landforms as indicators of ice-flow directions, and (3) Former path of the old Wisconsin or some other river prior to being rerouted by the Green Bay Lobe. GIS analysis is also performed in order to test published interpretations of the regional glacial history. This study confirms that glacial features observed today are consistent with the former advance of the Green Bay Lobe into the area, formation of glacial Lake Wisconsin, plugging of Devil''s Lake Gorge by a moraine to form Devil''s Lake, and subsequent glacial retreat leading to the breaching of an ice dam and catastrophic flooding by ~14,000years ago. The large aerial coverage of satellite imagery with resolutions up to 15m are valuable for reevaluating regional interpretations previously based on local field mapping and aerial photography of limited extent. [Copyright &y& Elsevier]

Abstract: The Bäke creek valley is part of the young morainic area in Berlin. Its origin is related to meltwater flow and dead-ice persistence resulting in a valley with a lake–creek system. During the Late Glacial, the slopes of the valley were affected by solifluction. A Holocene brown soil developed in this material, whereas parts of the lakes were filled with limnic–telmatic sediments. The excavation site at Goerzallee revealed Bronze Age and Iron Age burial places at the upper part of the slope, as well as a fireplace further downslope, but the slope itself remained stable. Only German settlements in the 12th and 13th centuries changed the processes in the creek–lake system: the construction of water mills created a retention system with higher ground water levels in the surrounding areas. On the other hand, deforestation on the till plain and on the slope triggered erosion. Therefore, in medieval time interfingering organic sediments and sand layers were deposited in the lower part of the slope on top of the Holocene soil. The new soil which formed on top of these sediments was transformed by ploughing until the 19th century. In 1905/06 the lower part of the slope was reshaped by the construction of the Teltow Canal, following the valley of the former Bäke creek. Finally, the whole area was levelled by infill after World War II. [ABSTRACT FROM AUTHOR]

Abstract: Moraine and glacier dams bordering the Homathko Icefield in the southern British Columbia Coast Mountains failed in the 1980s and 1990s, causing catastrophic downstream floods. The largest of the floods occurred in August 1997 and was caused by overtopping and rapid breaching of the moraine dam that impounds Queen Bess Lake. The floodwaters from Queen Bess Lake eroded Holocene-age sedimentary deposits along the west fork of Nostetuko River and caused a steep rise in the hydrograph of Homathko River at the head of Bute Inlet, ∼115km downstream. A field investigation of the eroded valley fill in 2008, revealed multiple paraglacial valley-fill units, many of which are capped by in situ stumps and woody detritus. Dendrogeomorphological field techniques were employed to develop a chronology for the buried forests. A regional tree-ring chronology spanning the interval CE 1572–2007 was constructed from living subalpine fir (Abies lasiocarpa) trees at seven sites in the southern Coast Mountains. In cases where subfossil stumps and boles predated the regional chronology, relative death dates constrained by radiocarbon ages were assigned to floating chronologies. By combining these dendrogeomorphological dating methods, we identified six floodplain aggradation episodes within the past 1200years. Comparison to local and regional glacial histories suggests that these events reflect climate-induced Little Ice Age changes in local glacier cover. [Copyright &y& Elsevier]

Abstract: This paper presents a framework for Late Quaternary lake-level fluctuation in the closed-basin lake “Lake Karakul” (eastern Pamir) on the basis of the stereoscopic observation of remote sensing data, field mapping and relative dating. The palaeoshorelines (approximately 60 in number) observed around the Lake Karakul can be classified into four groups: H Shorelines, M Shorelines, L Shorelines and LL Shorelines (in the descending order of height). The highest level of each of the above palaeoshoreline groups is 205m, 85m, 35m and 10m above the present lake level (3915m asl). From the glacial landform developments and related valley-fill sedimentation patterns around the threshold of the present basin closure, the lake-level fluctuation defined by these palaeoshoreline groups was found to be a consequence of the water balance change within the closed basin. With respect to the timing of the palaeolake highstands, the relationship between lacustrine terraces and terminal moraines suggests the synchroneity of the highest stand of each palaeolake with the corresponding maximum glacier advance. The tentative chronology of the lake-level fluctuation was established from the synthesis of the style of geomorphic development and related glaciation, relative dating on moraine gravels, and the correlations to established glacial histories in and around the Pamir. The periods of the palaeolake highstands indicated by H, M, L and LL shorelines seem to be correlated with the antepenultimate glacial (MIS 8), penultimate glacial (MIS 6), early last glacial (MIS 4) and the late last glacial (MIS 2) periods, respectively. Based on this chronology, each of the 60 palaeoshorelines are expected to show stable lake surfaces during lake regressive stages toward the terminations from the glacial maxima of MIS 8, 6, 4 and 2. Given that the distinct landforms of each palaeoshoreline group were formed in association with the predominant stagnation or small re-transgression of the palaeolake, the short-term cooling and/or wetter episodes, which turned positive lake hydrologic balances from negative ones, were superimposed on the major palaeoclimate changes during the glacial termination periods. [Copyright &y& Elsevier]

Abstract: The formation of terminal moraines dating from glacier advances during the A.D. 1990s was investigated at six temperate glaciers in the Jostedalsbreen and Jotunheimen regions of southern Norway. Morphological and sedimentological information was analysed and combined with detailed observations, photographic evidence, and length variation measurements. Bulldozing (pushing) of proglacial sediments was the predominant process at the low-lying glacier termini of the debris-free outlets of the Jostedalsbreen ice cap. Evidence for bulldozing includes the relocation and rotation of boulders and the presence of lichen-covered boulders in the distal slopes of moraines. Differences in moraine sedimentology between the individual sites are attributed to variations in the pre-existing material pushed up, rather than to specific processes. In Jotunheimen, several modes of moraine-ridge formation were active: dumping of supraglacial debris and the marginal freezing-on and subsequent melting-out of subglacial sediment slabs were more important than bulldozing at some sites and in some years. Low air temperatures in winter at the higher altitude glacier termini enabled freezing-on to occur. However, the forelands are below the lower limit of discontinuous permafrost and evidence of thrusting is absent. Whereas discrete terminal moraine ridges at Jostedalsbreen are related to (seasonal) advances, the less dynamic glaciers of Jotunheimen allow the accretion of successive ridges during consecutive years. No single regional mode of moraine formation is characteristic for southern Norway: several processes are involved depending on individual glacier morphology and dynamics, the glaciological regime, and environmental conditions (especially climate) on the glacier forelands. The importance of specific processes varies within and between glacier forelands. Thus, spatial and temporal variation and local individuality has to be taken into account in the interpretation of moraine-ridge formation. Similar variability is likely to have been characteristic of terminal moraines deposited during the “Little Ice Age” and earlier in the Quaternary. [Copyright &y& Elsevier]