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Our understanding of the response of the Antarctic ice sheet to climate and ocean changes requires the improvement of current ice-atmosphere-ocean models and the accurate determination of boundary conditions such as ice thickness and extent at key time intervals, so that satellite gravity observations and isostatic models can be adjusted. However, large portions of the Antarctic margin remain understudied or lack suitable data. One key area where data are lacking, is the Sabrina Coast portion of the East Antarctic Ice Sheet (EAIS) margin where the Totten Glacier, which has the largest ice discharge in East Antarctica, is accelerating, thinning and loosing mass at high rates. In this work, we present the results of the first geological and geophysical marine survey to the continental shelf offshore of the Dalton Ice Tongue and Moscow University ice shelf, east of the Totten Glacier. The data presented include multibeam swath bathymetry and multichannel seismic, focusing on the sea floor morphology and sedimentary section above a regional angular unconformity separating pre- and post-Miocene glacial strata. Sea floor scouring and iceberg keel marks on the outer shelf, associated with gullies on the upper slope indicate that ice expanded in the past and grounded ~5 km from the shelf edge at ~450–500 mbsl, extending ~155 km north of the current Moscow University Ice Shelf. A nearly 1000 m deep area in the inner-middle shelf, oriented NW with paleo-ice flow direction indicated by mega scale glacial lineations (MSGL) and drumlins, is interpreted as a cross shelf glacial trough. A series of geomorphic associations on the north-eastern side of the glacial trough includes glacial lobes, grounding zone wedges (GZW), glacial lineations and transverse ridges, which indicates slower ice, grounding line stabilization and collapse. These geomorphic associations are organized in 4 four sets representing different past ice-flow configurations reflecting changes in ice flow direction, grounding line position, location of fast and slow ice areas, and retreat pattern. Some of the geomorphic features identified are compatible with the presence of an organized subglacial drainage, and others are with rapid grounding line collapse. A well-preserved series of GZWs occurring at different water depths implies they were formed during different glacial stages or cycles. The inferred diminishing ice thickness for consecutives GZWs indicates that the margin of the Antarctic ice sheet evolved to a less extensive coverage of the continental shelf through successive glacial stages or cycles. The identification of different ice flow configurations, evidence of subglacial water and past ice margin collapse indicates a dynamic ice sheet margin with varying glacial conditions and retreat modes. We observe that some of the described morphological associations are similar to those found in the Amundsen sea sector of the West Antarctic Ice Sheet (WAIS) where they are associated with ice sheet and ice stream collapse. Although further studies are needed to assess the precise timing and rates of the glacial processes involved, we conclude that there is enough evidence to support the hypothesis that the EAIS margin can behave as dynamically as the WAIS margin, especially during glacial retreat and icesheet margin collapse.

High-resolution sediment echosounder data combined with radiocarbon-dated sediment cores allowed us to reconstruct the Late Quaternary stratigraphic architecture of the Kveithola Trough and surrounding Spitsbergenbanken. The deposits display the successive deglacial retreat of the Svalbard-Barents Sea Ice Sheet. Basal subglacial till indicates that the grounded ice sheet covered both bank and trough during the Late Weichselian. A glaciomarine blanket inside the trough coinciding with laminated plumites on the bank formed during the initial ice-melting phase from at least 16.1 to 13.5 cal ka BP in close proximity to the ice margin. After the establishment of open-marine conditions at around 13.5 cal ka BP, a sediment drift developed in the confined setting of the Kveithola Trough, contemporary with crudely laminated mud, an overlying lag deposit, and modern bioclastic-rich sand on Spitsbergenbanken. The Kveithola Drift shows a remarkable grain-size coarsening from the moat towards the southern flank of the trough. This trend contradicts the concept of a separated drift (which would imply coarser grain sizes in proximity of the moat) and indicates that the southern bank is the main sediment source for the coarse material building up the Kveithola Drift. This depocenter represents, therefore, a yet undescribed combination of off-bank wedge and confined drift. Although the deposits inside Kveithola Trough and on Spitsbergenbanken display different depocenter geometries, time-equivalent grain-size changes imply a region-wide sediment-dynamic connection. We thus relate a phase of coarsest sediment supply (8.8–6.3 cal ka BP) to an increase in bottom current strength, which might be related to a stronger Atlantic Water inflow from the Southeast across the bank leading to winnowing and off-bank export of sandy sediments.

Glacial-geomorphic studies provide vital information to make inferences about the effect of glacial advance and retreat on the geomorphology of an area. In the present study, glacial-geomorphic landforms of the Thajwas glacial valley in the upper reaches of the Indus, Kashmir Himalayas were mapped using geospatial technology validated with GPS-based field observations and ground photography. The glacial-geomorphic landforms were digitized using ASTER DEM (30 m resolution), Landsat ETM+ satellite imagery (30 m resolution) and Google Earth (1 m resolution) data. Results showed that Google Earth imagery, supported by field validation, is very useful for the interpretation of glacial-geomorphic landscapes and relief features at micro- and meso-scales. However, morphometric characteristics of landforms are best obtained using DEM overlaid onto the Landsat ETM+ satellite data. Glaciers in the valley are presently confined along the south and southwestern slopes. However, the significant role played by glaciers in shaping the geomorphic landforms and their subsequent preservation within the scenic landscape under the Late Quaternary climatic conditions are remarkably evident. The glacial-geomorphic landforms, especially terminal moraine, glacial trough and cirques observed in the valley aided the reconstruction of palaeo-glacial setting of the area. Morphology, shape and location of terminal and lateral moraine ridges were used to establish the palaeo-glacial extents, glacial volume and the number of glacial advances of the Thajwas glacier. The maximum elevation of the lateral moraines was used to define the former Equilibrium-Line Altitude (ELA). The greater rock excavation to form a large valley during the last glacial maximum might have induced isostatic rock uplift/exhumation in the glacier source area. It is observed that the concomitant retreat of the north-facing glacial cirques has played an important role in expanding the glacial valley and limiting the topographic relief.

Evidence of widespread alpine glaciations during the Late Pleistocene in mid-latitudes has long attracted attention of researchers. However, there were no studies that contain absolute ages in the Lesser Caucasus despite the fact that it is one of the major glaciated regions in Eurasia. Here, we present first cosmogenic 36Cl surface exposure ages from the Karcal Mountains (41.24° N, 42.06° E, 3431 m a.s.l., above sea level) which is located in the most western part of the Lesser Caucasus in the northeastern Anatolia. In the Karcal Mountains, there are numerous valleys that have experienced significant glaciations since Late Pleistocene. We have investigated one of the largest valleys, the east-facing Karcal Valley, that hosts even a small (2926 m a.s.l.) recent glacier located at above 3000 m a.s.l. Fossil and recent rock glaciers along with lateral and recessional moraines exist in the valley. We conducted the study in two stages. First, we mapped the geomorphological units in the Karcal Valley in detail based on our field works and aerial photography. Later, we collected 10 rock samples from the fossil rock glacier and recessional moraines for cosmogenic 36Cl surface exposure dating. The results outline a glacial chronology that is typical of the Last Glacial Maximum. Although the maximum extent and timing of the glaciation is not exactly known as lateral and terminal moraines were not suitable for sampling, recessional moraines indicate that the Karcal Valley palaeoglacier deglaciation started at least 19.9 ± 1.2 ka ago. Fossil rock glacier samples were dated to 15.7 ± 1.3 ka. These quantitative results are first in the Lesser Caucasus and compatible with previous ages obtained from other valleys in the nearby Eastern Black Sea region, Anatolian and some of the European Mountains.

Quaternary valley fills and landforms in the Waqia valley of the Chinese Pamir were examined using geomorphic mapping, geomorphic and sedimentological analysis of landforms and sediments, and cosmogenic 10Be surface exposure dating. Six sets of moraines (M-1 to M-6) are identified and date to the penultimate or an older glacial cycle (M-1), penultimate glacial cycle (M-2), early last glacial and probably Marine Oxygen Isotope Stage (MIS) 4 (M-3), MIS 2 (M-4), Late Glacial (M-5), and early Holocene (M-6). Younger moraines are also present, but these were not examined in detail. Alluvial fans and outwash/river terraces are present throughout the valley. Four surfaces on alluvial fans and river terraces were dated to ~ 580 ka (T-1), ~ 120 ka (T-2), ~ 100 ka (T-3), and ~ 70 ka (T-4). Large landslide and lacustrine deposits are common within the valley fills and represent periods of major slope instability and possible damming of drainages. Glacial processes dominate the western side of the valley; landsliding is the leading process on its eastern side. Defining the nature and timing of landform formation in this valley highlights the punctuated nature of landform evolution in the Himalaya and Tibet and provides a framework for considering the abundant valley fill successions elsewhere in the orogen.

In the present study, the retreat of Kolahoi glacier was mapped from the satellite observations and historical maps supplemented by the extensive field observations to understand the recent deglaciation of the Kolahoi valley, Kashmir Himalaya, India. The glacier has retreated by 2.85 km during the last 157 years from 1857 to 2014 with an average retreat of about 18.2 m year−1; however, the glacier snout has shown higher recession during the last decade. The geomorphological evidence reveals glaciation of the Kolahoi valley during the Quaternary. These evidences include glacial till at Pahalgam and Aru besides terminal and lateral moraines at Lidderwat, Satlanjan and Kolahoi Gunj in the Kolahoi valley. The glacier has shrunk by 2.81 km2 during the last 51 years (1962–2013) losing an ice volume of 0.30 km3. The observed glacier changes were correlated with the climate data from PMIP3-CMIP5 models. The temperatures are predicted to increase almost ten times more than that observed during the Last Glacial Maximum (LGM). The future temperature is predicted to rise between 0.18 °C and 0.61 °C per decade under RCP 2.6 and RCP 8.5 respectively. The projected rise in the temperature, if realized, will have an adverse effect on the glaciers and would, in all likelihood, adversely affect the water availability for various sectors in the region.

Reconstruction based on the geomorphology, lateral moraine stratigraphy, and limited optical chronology indicate that the monsoon-dominated Kosa Valley experienced four glacial advances during the late glacial to late Holocene. The oldest and most extensive glaciation, which is termed as Raj Bank Stage-1 (RBS-1), is represented by the degraded moraine ridge. This glaciation remains undated; however, the chronology of outwash terrace gravel dated to 12.7 ± 1.3 ka indicates that the RBS-1 probably represents the Last Glacial Maximum (LGM). The second glacial advance (RBS-2) is preserved as a curvilinear lateral moraine and is dated to 6.1 ± 0.4 ka. The third glacial advance viz. RBS-3 is bracketed between 5.0 ± 0.5 and 4.0 ± 0.4 ka. Following this, the glacier receded in pulses that are represented by two distinct recessional moraines (RBS-3a and b). The forth glacial stage (RBS-4), which is dated between 2.2 ± 0.2 and 1.6 ± 0.2 ka, shows a pulsating recession and is represented by a prominent recessional moraine (RBS-4a). Whereas, presence of unconsolidated, poorly defined moraine mounds proximal to the glacier snout are ascribed as neoglacial advance corresponding to the Little Ice Age (LIA). With the limited chronometric data, we speculated that the glaciation was driven during the weak to moderate Indian Summer Monsoon (ISM) aided by lowered temperature. Presence of recessional moraines associated with mid-Holocene glacial phase indicate that the monsoon-dominated glaciers respond sensitively to minor (sub-millennial scale) changes in temperature and precipitation conditions. The observations are broadly in accordance with the studies carried out in other monsoon-dominated valleys in the central Himalaya, implying that in ISM dominated regions, lowered temperature seems to be the major driver of glaciations during the late glacial to late Holocene.

Apatite thermochronometry and synthetic maps of ages and rates for thermochronometric data are used to estimate the timing of incision of valley relief in the Andes. Central Patagonia offers a unique location to study the feedbacks between long-term climate, topography, and erosion due to the high relief and well-resolved mid-latitude glacial history. New apatite (U–Th)/He ages from two vertical transects and two 4He/3He release spectra in the fjord network around 47°S reveal fast cooling (15–30 °C/Ma) from ∼10 to 5 Ma. Samples currently at the surface cooled below ∼35 °C by ∼5 Ma, indicating slow cooling and little erosion in those regions since 5 Ma. We show that these very low-temperature thermochronometric data are useful indicators of changes in topography, and insensitive to deep thermal processes, such as migration of the Chile triple junction. Map-based predictions of the thermochronometric signatures of disparate topographic scenarios show the distribution of sample data necessary to resolve the timing of relief change. Comparisons to predicted cooling ages and rates indicate that our new apatite He data are most consistent with a pulse of early glacial incision, with much of the observed valley relief in Patagonia carved between 10 and 5 Ma. Early onset of glaciation in Patagonia is supported by glacial till with bracketing ages of 7.4 and 5 Ma. We therefore conclude that the observed thermochronometric signal of fast cooling from 10 to 5 Ma is likely due to an increase in valley relief coinciding with these early glaciations in the Andes. In other glaciated areas at lower latitudes, studies have found a dramatic increase in valley relief at ∼1 Ma. This timing has generated the idea that incision of glacial valleys may be related to the mid-Pleistocene transition, when the global glacial cycle changed from 40 to 100 ka periods. Our results from a higher latitude indicate an alternative, that glacial valleys incised rapidly after the onset of alpine glaciation.

We present new data on the Vichigasta Carboniferous paleovalley, a glacial trough crucial to understand the type of glaciation that affected western Gondwana during the Late Paleozoic Ice Age (LPIA). The filling of this paleovalley starts soon after the mid-Carboniferous glacial peak. Stage I represents pro-glacial lacustrine deposits with outwash, glacially rafted dropstones, mass transport deposits (MTDs) and turbidites of the trunk and a lateral tributary valley. Base-level drop created the scenario for Stage II outwash deltas and sandur deposits, with westward flow. Stage III represents a flooding at the base of the Bashkirian, characterized by typical transgressive dark shales and distal turbidites. Stage IV represents a highstand prograding turbidite wedge. We worked in a detailed terrain analysis, surveyed the scarce sedimentary record left and recovered a rich palynoflora from mudstones of Stage 3. The almost complete erosion of the fill allowed us to analyze the shape of this paleovalley and compare it to Olta and Malanzan ones. Vichigasta and Malanzan paleovalleys show similar size, a clear U-shape and regular and homogeneous width downslope, a requisite for bypass glacial paleovalleys carved in a subcrop of homogeneous composition (basement), which allow us to interpret them as outlet valleys. Olta paleovalley ranks as tributary as its capacity is only one-third of the others. We also identified a basement high over the Vichigasta valley floor that suggests the presence of a potential drumlin supporting our interpretation as a bypass glacial valley. This post-glacial flooding event is widely observed at other glacial valleys as the Olta-Malanzan herein analyzed and others like Las Lajas and Quebrada Grande. The new data from Vichigasta paleovalley reinforce the hypothesis of a large ice-sheet located to the east of the craton.

The existence of plateau ice fields in the Southern Carpathians has long been suggested due to the widespread presence of the Borascu surface in the region. The Borascu surface is a peneplain consisting of flat plateaus in the elevation range of 1800–2200 m a.s.l. It is present throughout the Southern Carpathians with the most typical appearance in the Godeanu Mountains. These plateaus could have served as ice accumulation sites during the Pleistocene glaciations as they were well above the steady-state equilibrium-line altitude (ELA 0 ). Direct geomorphological evidence on the existence of plateau ice fields, and thus well founded reconstructions, are absent due to the lack of glacial landforms on the plateaus. In order to test the existence of plateau ice fields a previous geomorphological survey and theoretical ice surface profiles, based on a steady-state perfectly plastic ice flow model, were used. Based on these methods maps and three-dimensional surface models of the former glaciers were created. The ELA 0 s of the paleoglaciers were estimated by the accumulation-area ratio (AAR) method. According to our results, three major ice fields on the central plateaus and several smaller ice fields on wide saddles were present in the Godeanu Mountains during the maximal glaciation. The ice fields fed numerous surrounding valley glaciers. Several independent valley and cirque glaciers, completely separated from the ice fields, were also present further from the central mass of the mountain range. The average ELA 0 of the northern, 1855 ± 2 m a.s.l., and the southern, 1700 ± 2 m a.s.l., glaciers differed greatly. We suggest that the surprisingly high average ELA 0 of the northern glaciers was mostly caused by the missing lower sections of these paleoglaciers from our reconstructions, due to the destroyed terminal glacial landforms. However, the terminal glacial landforms are quite well preserved in the southern valleys. Thus, the average ELA 0 of the southern paleoglaciers was suitable to correlate the maximal glaciation of the Godeanu Mountains with the maximal glaciation of the neighbouring Retezat Mountains.

Rebesco, Michele ... et al.-- Special Issue: PAST Gateways (Palaeo-Arctic Spatial and Temporal Gateways).-- 16 pages, 12 figures, 2 tables, supplementary data http://dx.doi.org/10.1016/j.quascirev.2016.02.007, Kveithola is a glacially-carved, E-W trending trough located in the NW Barents Sea, an epicontinental shelf sea of the Arctic Ocean located off northern Norway and Russia. A set of confined sediment drifts (the “Kveithola Drift”) is located in the inner part of the trough. In general, drift deposits are commonly characterized by high lateral continuity, restricted occurrence of hiatuses and relatively high accumulation rates, and thus represent excellent repositories of paleo-environmental information. We provide for the first time a detailed morphological and seismostratigraphic insight into this sediment drift, which is further supported by some preliminary lithological and sedimentological analyses. The complex morphology of the drift, imaged by combining all available multibeam data, includes a main and a minor drift body, two drift lenses in the outer part of the trough, more or less connected drift patches in the innermost part and small perched sediment patches in a structurally-controlled channel to the north. The seismic (PARASOUND) data show that the main and minor drift bodies are mainly well-stratified, characterized by sub-parallel reflections of moderate to high amplitude and good lateral continuity. The reflectors show an abrupt pinch-out on the northern edge where a distinct moat is present, and a gradual tapering to the south. Internally we identify the base of the drift and four internal horizons, which we correlate throughout the drift. Two units display high amplitude reflectors, marked lensoidal character and restricted lateral extent, suggesting the occurrence of more energetic sedimentary conditions. Facies typical for contourite deposition are found in the sediment cores, with strongly bioturbated sediments and abundant silty/sandy mottles that contain shell fragments. These characteristics, along with the morphological and seismic information, suggest a strong control by a bottom current flowing along the moat on the northern edge of the drift. Though both Atlantic and Arctic waters are known to enter the trough, from the west and the north respectively, brine-enriched shelf water (BSW) produced during winter and flowing westward in the moat, is suggested to be responsible for the genesis of the Kveithola Drift. The formation of BSW is inferred to have started around 13 cal ka BP, the onset of drift deposition, suggesting that conditions leading to atmospheric cooling of the surface waters and/or the presence of coastal polynyas and wind or floating ice shelves have persisted on the western Barents Shelf since that time. The units inferred to have been deposited under more energetic sedimentary conditions (tentatively dated to the Younger Dryas and to 8.9–8.2 cal ka BP) are suggestive of stronger BSW formation. In general, we infer that variations in the bottom current regime were mainly related to BSW formation due to atmospheric changes. They could also have been a response to successive episodes of grounded and sea ice retreat that allowed for a first limited, later open shelf current, which progressively established on the western Barents Sea shelf, The research cruise MSM30 CORIBAR and this study were partly funded through the MARUM DFG-Research Center/Cluster of Excellence “The Ocean in the Earth System” as part of MARUM project SD-2. This study contributes to the IPY initiative 367 NICESTREAM (Neogene Ice Streams and Sedimentary Processes on High- Latitude Continental Margins). The work was funded by the Italian projects OGS-EGLACOM, PNRA-CORIBAR-IT (PdR 2013/C2.01), ARCA (grant n. 25_11_2013_973) and PNRA-VALFLU, by the Council of Norway through its Centres of Excellence funding scheme (project number 223259), by the Spanish projects DEGLABAR (CTM2010-17386) and CORIBAR-ES (CTM2011-14807-E) funded by the “Ministerio de Economia y Competitividad”. The “Generalitat de Catalunya” is acknowledged for support through an excellence research group grant (2014SGR940). J.L. was funded by an FPI grant BES-2011-043614

Fluvial, glacial, and estuarine deposits in the Delaware Valley record the response of the Delaware River to glaciation, sea-level change, and glacioisostasy during the Quaternary. Incision following an early Pleistocene glaciation created the present valley, which is inset into a Pliocene strath and fluvial plain. Middle and upper Pleistocene and Holocene deposits were laid down in this inset valley. Estuarine terraces in the lower valley and bayshore at + 20 m (probably Marine Isotope Stage [MIS] 11), + 8 m (MIS 5e), and + 3 m (MIS 5a or c), and a fluvial deposit that correlates to offshore MIS 3 marine deposits at − 20 m are at elevations consistent with glacioisostatic models. Successive incisions during lowstands in the middle and late Pleistocene lengthened, deepened, and narrowed the channel in the lower valley and shifted the channel westward in Delaware Bay. During MIS 2 glaciation, from 25 to 18 ka, the Delaware was diverted to the Hudson Shelf Valley by glacioisostatic tilting. Most glacial sediment was trapped in fluvial-lacustrine valley fills north of the terminal moraine. Incision of the valley fill was accomplished during the early stage of rebound, between 17 and 12 ka. Drainage to the Delaware shelf was restored between 15 and 13 ka as the forebulge collapsed. During incision, multiple postglacial terraces formed where the valley was perpendicular to rebound contours and so was steepened and elevated northward; and a single terrace formed where the valley paralleled the contours, and there was no differential elevation or steepening. About 65% of the original volume of MIS 2 glacial sediment remains in the main valley, and most of the eroded volume is in the channel in the lower valley beneath Holocene estuarine fill. Little glacial sediment reached the Delaware or Hudson shelf. Overbank deposition on the lower postglacial terrace and modern floodplain spans the Holocene. The volume of Holocene sediment in the estuary and bay yields a basinwide denudation rate of about 20 m/my.

Mountain glaciers advance and retreat primarily in response to changes in climate. Establishing the timing and magnitude of mountain glacier fluctuations from geological records can thus help to identify the drivers and mechanisms of past climate change. In this study, we use cosmogenic 3He surface exposure dating and tephrochronology to constrain the timing of past glaciation on Tongariro massif in central North Island, New Zealand (39°S). Exposure ages from moraine boulders show that valley glaciation persisted between c. 30–18 ka, which coincides with the global Last Glacial Maximum. Reinterpretation of moraine tephrostratigraphy, using major element geochemistry analysis, shows that ice retreat and climatic amelioration at the last glacial termination was well underway prior to 14 ka. The equilibrium line altitude in central North Island, during the Last Glacial Maximum, was c. 1400–1550 m above sea level, which is c. 930–1080 m lower than present. Considering the uncertainties in the glacial reconstruction and temperature lapse rates, we estimate that this equilibrium line altitude lowering equates to a temperature depression of 5.6 ± 1.1 °C, relative to present. Our mapping and surface exposure dating also show evidence for an earlier period of glaciation, of similar magnitude to the Last Glacial Maximum, which culminated prior to 57 ka, probably during Marine Isotope Stage 4. Good agreement between the timing and magnitude of glacier fluctuations in central North Island and the Southern Alps indicate a response to a common climatic forcing during the last glacial cycle.

Successively smaller glacial extents have been proposed for continental Eurasia during the stadials of the last glacial period leading up to the Last Glacial Maximum (LGM). At the same time the large mountainous region east of Lake Baikal, Transbaikalia, has remained unexplored in terms of glacial chronology despite clear geomorphological evidence of substantial past glaciations. We have applied cosmogenic Be-10 exposure dating and optically stimulated luminescence to establish the first quantitative glacial chronology for this region. Based on eighteen exposure ages from five moraine complexes, we propose that large mountain ice fields existed in the Kodar and Udokan mountains during Oxygen Isotope Stage 2, commensurate with the global LGM. These ice fields fed valley glaciers (>100 km in length) reaching down to the Chara Depression between the Kodar and Udokan mountains and to the valley of the Vitim River northwest of the Kodar Mountains. Two of the investigated moraines date to the Late Glacial, but indications of incomplete exposure among some of the sampled boulders obscure the specific details of the post-LGM glacial history. In addition to the LGM ice fields in the highest mountains of Transbaikalia, we report geomorphological evidence of a much more extensive, ice-cap type glaciation at a time that is yet to be firmly resolved. (C) 2015 Elsevier Ltd. All rights reserved.

The Piec Stawow Polskich-Roztoka Valley in the High Tatras (Western Carpathians) features typical alpine-type relief with a deeply incised glacial trough and large, compound trough head cirque. The prominent hypsographic maximum in the valley (1680–2000 m) along with a broad cirque bottom had provided a vast space for recording glacial and periglacial landforms, specifically the most recent Lateglacial advances. The valley has been intensively studied before in the context of glacial chronology. In this paper, we re-establish the post-Last Glacial Maximum (LGM) glacial chronology of the valley via detailed geomorphologic mapping, equilibrium line altitude (ELA) reconstruction, and Schmidt hammer (SH) dating, along with a critical review of previously published cosmogenic exposure age data ( 36 Cl) and lacustrine sediment chronology. Our results indicate that the first four of the five distinguished Lateglacial stages (Roztoka I–III, Pusta I) occurred before the Bolling/Allerod (B/A) interstadial; thus, virtually the entire valley became deglaciated in course of the Oldest Dryas cold phase. A distinct reorganization of deglacial patterns from valley-type to marginal-type occurred before B/A warming when the ELA increased above the valley hypsographic maximum concentrated at the cirque bottom elevation. It shows that noticeable deglaciation step can be caused due to topographic reason with a minimal climate forcing. This points also to an important role of glaciated valley hypsography in regulating the distribution of moraines which is rarely taken into account in paleoglaciological reconstructions. We infer that glaciers vanished in the Tatra Mountains during the B/A interstadial. Later, a renewed advance during the Younger Dryas (Pusta II) formed a nearly continuous, festoon shaped pattern of moraines and rock glaciers in close distance to cirque backwalls. Furthermore, we discus some paleoenvironmental significance of the geomorphological record in the valley, as well, the applicability of SH dating in constructing glacial chronology.

Glacial landforms are well preserved on Taibai Mountain (3767 m), the main peak of the Qinling mountain range located south of the Loess Plateau and east of the Qinghai-Tibet Plateau. The timing and extent of Quaternary glaciation in the study area is important for reconstructing Quaternary environmental change however numerical ages for glaciation in this study area have not previously been well resolved. Using terrestrial in situ cosmogenic nuclides we dated four samples collected from two glacially eroded rock steps in the upper part of a valley near the main peak, in an area previously identified as having been occupied by ice during the Taibai glaciation. The 10Be results are all late glacial in age: 18.6 ± 1.1 ka, 16.9 ± 1.0 ka, 16.9 ± 1.1 ka and 15.1 ± 1.0 ka. The spatial pattern of ages in the valley suggests fast retreat, with horizontal and vertical retreat rates estimated to be on the order of 0.4 and 0.09 m a−1, respectively. A simple extrapolation of these retreat rates from the ages at the two sample sites suggests that the glacier retreat began during Last Glacial Maximum and that glaciers disappeared from the main peak by about 15 ka.

Landslide dams form when a landslide obstructs narrow and steep valleys in mountainous areas. Since these dams may fail over a short time and cause secondary geological disasters in the downstream area, the stability of such dams must be assessed in an accurate and timely manner. The three-dimensional (3-D) geometry of a landslide dam, which is one of the essential indices for stability analyses, is highly influenced by the landslide dam formation conditions, including the sliding surface dip-angle and the valley topography. However, few studies have focused on the correlation between the 3-D geometry and formation conditions of a landslide dam. A photogrammetric system was used to develop a laboratory apparatus to simulate the formation process of a landslide dam and construct a digital model for the 3-D geometry of a landslide dam in a U-shaped valley. Then, a series of experiments were designed to systematically investigate the formation process and the 3-D geometry of landslide dams under different combinations of valley bed inclinations (0, 4°, 8°, and 12°) and sliding surface dip-angles (30°, 45°, 60°, and 75°). The results indicate that the sliding surface dip-angle has a significant effect on the length and height of a landslide dam, whereas the valley bed inclination has a limited effect on the length and height compared with its effect on the relative angles of a landslide dam. In addition, the cross-sectional profiles of landslide dams can be classified into three categories, namely, symmetric, asymmetric and flat shapes, and these profiles are predominantly affected by the sliding surface dip-angle instead of the valley bed inclination. Subsequently, a mathematical model for predicting the 3-D geometry of a landslide dam was presented according to the experimental results, and it was verified by the experimental data and 42 historical cases of landslide dams. Based on the proposed model, the predicted 3-D geometry of the Tangjiashan landslide dam triggered by the Wenchuan earthquake of 2008 was consistent with its actual geometry, which confirmed the reliability of the prediction model in practical applications. The findings of our study contribute to the establishment of evidence-based disaster prevention and mitigation measures for landslide dams.

Detailed field mapping of glacial and paraglacial landforms supported by optical and radiocarbon dating is used to reconstruct the history of late Quaternary glaciation and landform evolution in the Trans Himalayan region of the upper Dhauliganga valley. The study identifies four events of glaciations with decreasing magnitude which are termed as Purvi Kamet Stage -Ia (PKS-Ia), PKS-Ib, PKS-II, PKS-III and PKS-IV respectively. The oldest PKS-Ia and Ib are assigned the Marine Isotopic Stgae-3 (MIS-3), the PKS-II to the Last Glacial Maximum (MIS-2), PKS-III dated to 7.9 ± 0.7 ka, and the PKS-IV is dated to 3.4 ± 0.3 ka and 1.9 ± 0.2 ka respectively. The largest valley glaciations viz. the (PKS-Ia) occurred during the strengthened summer monsoon corresponding to the MIS-3, following this, the recessional moraines (PKS-Ib) represent the gradual decline in summer monsoon towards the later part of MIS-3. The valley responded to the global Last Glacial Maximum (LGM), which is represented by the PKS-II moraine implying the influence of strengthened mid-latitude westerlies during the LGM. The post-LGM deglaciation was associated with the onset of summer monsoon and is represented by the deposition of four distinct outwash gravel terraces. The early Holocene PKS-III glaciation occurred around 7.9 ± 0.7 ka and broadly coincides with the early Holocene cooling event (8.2 ka). This was followed by the deposition of stratified scree deposits and the alluvial fan (between 5.5 ka and 3 ka) during the mid to late Holocene aridity. This was followed by marginal re-advancement of the valley glacier (viz. PKS-IV) during the late Holocene cool and moist climate. Although glaciers respond to a combination of temperature and precipitation changes, however during the Holocene it seems that temperature played a major role in driving the glaciation.

During the late Quaternary, the Southern Alps of New Zealand experienced multiple episodes of glaciation with large piedmont glaciers reaching the coastal plains in the west and expanding into the eastern alpine forelands. Here, we present a new 10Be exposure age chronology for a moraine sequence in the Waimakariri Valley (N-Canterbury), which has long been used as a reference record for correlating glacial events across New Zealand and the wider Southern Hemisphere. Our data indicate that the Waimakariri glacier reached its maximum last glaciation extent prior to ∼26 ka well before the global last glaciation maximum (LGM). This was followed by a gradual reduction in ice volume and the abandonment of the innermost LGM moraines at about 17.5 ka. Significantly, we find that during its maximum extent, the Waimakariri glacier overflowed the Avoca Plateau, previously believed to represent a mid-Pleistocene glacial surface (i.e. MIS 8). At the same time, the glacier extended to a position downstream of the Waimakariri Gorge, some 15 km beyond the previously mapped LGM ice limit. We use a simple steady-state mass balance model to test the sensitivity of past glacial accumulation to various climatic parameters, and to evaluate possible climate scenarios capable of generating the ice volume required to reach the full local-LGM extent. Model outcomes indicate that under New Zealand's oceanic setting, a cooling of 5 °C, assuming modern precipitation levels, or a cooling of 6.5 °C, assuming a one third reduction in precipitation, would suffice to drive the Waimakariri glacier to the eastern alpine forelands (Canterbury Plains). Our findings demonstrate that the scale of LGM glaciation in the Waimakariri Valley and adjacent major catchments, both in terms of ice volume and downvalley ice extent, has been significantly underestimated. Our observation that high-lying glacial surfaces, so far believed to represent much older glacial episodes, were glaciated during the LGM, challenges the conventional geomorphic model of glaciation in New Zealand where the vertical arrangement of glacial landform-associations is used to assign successively older glaciation ages.

We present twenty-four new cosmogenic isotope ( 36 Cl) surface exposure ages from erratic boulders, moraine boulders and glacially eroded bedrock that constrain the late Weichselian to Holocene glacial history of the Drangajokull region, northwest Iceland. The results suggest a topographically controlled ice sheet over the Vestfirðir (Westfjords) peninsula during the last glaciation. Cold based non-erosive sectors of the ice sheet covered most of the mountains while fjords and valleys were occupied with erosive, warm-based ice. Old 36 Cl exposure ages from highlands and mountain plateaux (L8; 76.5 ka and H1; 41.6 ka) in combination with younger erratic boulders (L7; 26.2 and K1–K4; 15.0–13.8 ka) superimposed on such surfaces suggest the presence of non-erosive ice over uplands and plateaux in the Vestfirðir peninsula during the last glaciation. Glacially scoured terrain and erratic boulders yielding younger exposure ages (L1-L6; 11.3–9.1 ka and R1, R6-R7; 10.6–9.4 ka) in the lowland areas indicate that the valleys and fjords of the Vestfirðir peninsula were occupied by warm-based, dynamic ice during the last glaciation. The deglaciation of mountain Leirufjall by 26.2 ka BP suggests that ice thinning and deglaciation of some mountains and plateaux preceded any significant lateral retreat of the ice sheet. Subsequently this initial ice thinning was followed by break-up of the shelf based ice sheet off Vestfirðir about 15 ka BP. Hence, the new exposure ages suggest a stepwise asynchronous deglaciation on land, following the shelf break-up with some valleys and most of the highlands, ice free by 14–15 ka BP. The outermost moraine at the mouth of Leirufjorður is dated to 9.3 ka BP, and we suggest the moraine to be formed by a glacier re-advance in response to a cooler climate forced by the reduced Atlantic Meridional Overturning Circulation at around 9.3 ka BP. A system of moraines proximal to the 9.3 ka moraine in Leirufjorður as well as a 9.4 ka deglaciation age in the coastal area of Reykjarfjorður suggest that an extensive ice cap persisted over the eastern Vestfirðir peninsula at least until c. 9 ka BP.

We present a sensitivity analysis of the isochron approach of Goehring et al. (2013) for paired measurements of in situ14C/10Be from glacially sculpted bedrock surfaces. This analysis tests how sensitive the resulting exposure durations from this technique are to both the number of samples analyzed and their locations along a glacial trough transect, using a dataset from Goehring et al. (2011) as a test case. A simple equally weighted combinatorial approach was employed to (1) generate non-repetitive combinations of n subsets of samples arranged from the ten possible samples (where n

The study of glacial geomorphology in the Cantabrian Mountains, a mountain range that extends 460 km along the northern coast of the Iberian Peninsula (SW Europe), started late in the 19th century and continues nowadays with a growing number of research papers. However, the number and timing of glaciations remains poorly understood, partially due to the still limited number of numerical ages. Its southerly location and proximity to the Atlantic Ocean make this mountain range potentially sensitive to past climate fluctuations. This work updates the glacial knowledge evolution for the whole range, from the Queixa-Invernadoiro Massif to the Basque Mountains, reviewing: (i) the history of glacial research since the late 19th century; (ii) the methodological approaches applied to reconstruct both the spatial extent and timing of past glacial stages; and (iii) the main geomorphological and geochronological evidence reported until date, including glacial features attributed to the Last Glacial Cycle (last 120 ka) and previous glaciations. According to current knowledge, glaciers extended over the Cantabrian Mountains covering a total area of 3150 km2, showing asymmetric development conditioned by variations of the topographic configuration and moisture supply along the range. Available geochronology based on radiocarbon, optically stimulated luminescence and terrestrial cosmogenic nuclides suggests the occurrence of at least 2 glacial advances during the Last Glacial Cycle: (i) a glacial maximum stage that took place at a minimum age of 36–45 ka (Marine Isotope Stage 3) and (ii) a second glacial advance at 19–23 ka (MIS 2). In some areas the extent of the glacier tongues during the second glacial advance was comparable to previous glacial maximum and was followed by glacial retreat conditions with formation of recessional moraines. Asynchronous glacial maximum conditions have been reported only for the Castro Valnera (MIS 4, 3 numerical ages) and Queixa-Invernadoiro (MIS 6, 1 numerical age) massifs until now. Finally, geomorphological evidence reported in Picos de Europa has been attributed to prior glaciations and correlated to cold conditions recorded during MIS 12 and MIS 22 based on a very limited number of numerical ages.

The Tailan River originates on the southern slope of Tumur Peak, the largest center of modern glaciation in the Tianshan Range. Five moraine complexes and associated fluvioglacial deposits in this valley record a complex history of Quaternary glacial cycles and landform evolution. Electron spin resonance (ESR) dating of glacial sediments was carried out using germanium (Ge) centers in quartz grains, which are sensitive to both sunlight and grinding. Based on the dating results as well as geomorphic and stratigraphic data, the Piyazilike end moraines (the second moraine complex) were deposited during Neoglaciation (the largest glacial advances during the last 3–4 ka in western China) and an early Holocene glacial advance, the third set of moraines was deposited in marine isotope stage (MIS) 2–4, and the glacial landforms of the Tailan glaciation (the fourth moraine complex), which include hummocky moraines on the piedmont, were formed in MIS 6 (penultimate glaciation). The end moraines of the innermost moraine complex (the first moraine complex) are inferred to have been deposited during the Little Ice Age (LIA). Thus the landforms and dates indicate compound valley glaciers from the LIA to MIS 2–4, and piedmont glaciers during MIS 6. The oldest tills studied belong to the “Kokdepsang Glacial Stage”, and occur on a high plateau. Based on similar glacial landforms (glacial deposits on a high plateau and a high glacial terrace) and their ESR ages in adjacent valleys on the southern slope of Tumur Peak, the Kokdepsang Glacial Stage is assigned to MIS 12.

The Talacasto paleovalley is situated in the Central Precordillera of San Juan, Argentina, where upper Carboniferous-Permian rocks (Paganzo Group) rest on Devonian sandstones of the Punta Negra Formation. This outcrop is an excellent example of a glacial valley-fill sequence that records at least two high-frequency cycles of the advance and retreat of a glacier into the valley. The paleocurrent analysis shows transport predominantly to the south, indicating that at this site the ice flow differs from the other nearby paleovalleys. Evidence of the glacial origin of this valley can be seen in the glacial striae on the valley's sides, as well as the U-shape of the valley, indicated by very steep locally overhanging valley walls. Deglaciation is indicated by a set of retransported conglomerates deposited in a shallow-water environment followed by a transgressive succession, which suggests eustatic rise due to meltwater input to the paleofjord. The complete sedimentary succession records distinct stages in the evolution of the valley-fill, represented by seven stratigraphical units. These units are identified based on facies associations and their interpreted depositional setting. Units 1 to 5 show one cycle of deglaciation and unit 6 marks the beginning of a new cycle of glacier advance which is characterized by different types of glacial deposits. All units show evidence of glacial influence such as dropstones and striated clasts, which indicates that the glaciers were always present in the valley or in adjacent areas during sedimentation. The Talacasto paleofjord provides good evidence of the Late Paleozoic Gondwana glaciation in western Argentina and examples of sedimentary successions which have been interpreted as being deposited by a confined wet-based glacier in advance and retreat cycles, with eventual release of icebergs into the basin. The outcrop is also a key for reconstructing the local glacial paleogeography, and it suggests a new interpretation that is not in agreement with previous studies. Finally, the importance of the Talacasto paleovalley for the Paganzo basin lies in its orientation, because it allows the reconstruction of the ice paleoflow and indication, for the first time, that marine ingressions into this area were not taking place along the Jachal trough, as expected, but along a different connection to the sea, which for this work we will call the San Juan Paleotrough.

Our study in the Başyayla Valley in northeastern Anatolia showed evidence of four glacier advances that built terminal and lateral moraines. Surface exposure dating of boulders on these moraines showed that the Maximum Ice Extent (MIE) was asynchronous with the global Last Glacial Maximum (LGM; 22.1 ± 4.3 thousand years; ka). The local {MIE} took place at least 57.0 ± 3.5 ka ago. The extent of the Başyayla Glacier during this advance is not known exactly because the boulders are only preserved on a lateral moraine. The next advance was prior to 41.5 ± 2.5 ka, and it descended down the valley to approximately 2320 m above sea level (m a.s.l.), with a glacier length of 5.3 km. During the early global LGM, the Başyayla Glacier extended for a distance of 4.9 km down to approx. 2430 m a.s.l. The last recorded advance occurred during the global LGM. This extension was 0.7 km smaller than the local {MIE} and its terminus reached 2490 m a.s.l. only. The exposure ages of boulders in a retreat position at an altitude of approx. 3045 m a.s.l. indicate that the valley has remained ice-free since the Lateglacial period. Therefore, the Lateglacial extent was limited to the cirque system in the uppermost part of the catchment. Furthermore, Holocene glacier oscillations seem to be either absent or restricted to solifluction in the whole catchment and to rock glacier movements in the southern tributary of the Başyayla Valley system.

Reconstructing glacial chronologies with consistent methods is critical for efforts to examine the timing and pattern of past climate change. Cosmogenic 10Be surface exposure dating has been widely used to constrain the timing of glacial events on the Tibetan Plateau and in Central Asia. However, few such studies have been conducted in the Chinese Tian Shan and available 10Be ages from this region have only provided evidence for glacial events during the global Last Glacial Maximum (gLGM) and Lateglacial. Here, we present 45 10Be surface exposure ages from glacial landforms in the Ala and Daxi valleys, two formerly glaciated valleys draining the Tianger Range, eastern Tian Shan. Combined with previously published 10Be surface exposure ages from the Daxi Valley in the source area of the Urumqi River, the new ages record five major glacial events during Marine Oxygen Isotope Stages (MIS) 6 or older, 4, 3, 2, and 1 (during the Little Ice Age, LIA). Landforms from glacial events since MIS 2 are found on the northern slope of the Tianger Range (Daxi Valley), whereas evidence for the older glacial events is only preserved on its southern slope (Ala Valley). This disparity may be caused by different preservation- and micro-climatic conditions on the northern and southern slopes of this mountain range, due to differences in gradient and aspect. The LIA glacial advances are apparently the only Holocene glacial event recorded in this area. Earlier Holocene glacial events were probably so restricted in extent that they were destroyed by subsequent LIA advances.

Investigations in sections along the rivers Severnaya Dvina and Vaga, and morphological mapping based on a new digital elevation model and Landsat imagery, allow for a reinterpretation of the extent of the Scandinavian Ice Sheet during the Last Glacial Maximum (LGM). The reconstruction provides a much better link between stratigraphical and morphological expression of glaciation than previous proposals. Most striking is the configuration of long, low-gradient ice-lobes (ice-streams) extending for some 300–400 km up the wide and smooth river valleys. Their extremely low surface gradients are evidenced by glacial trimlines that formed along the sides of the ice-lobes in contact with the gentle valley slopes. In the main valleys, end moraines marking terminal positions are present, whereas drumlins are rare in the peripheral areas of the ice sheet but found in some tributary valleys at somewhat higher elevations. Large drumlin fields, however, are found farther up-ice. The glacial sediment succession is composed of waterlain sediments and tills. The sediments provide evidence of distal ice damming, glacier overriding and retreat, and finally distally glaciolacustrine sedimentation and lake drainage. The diamicton unit associated with the LGM shows evidence of basal coupling, although more striking is the abundant evidence for ice–bed decoupling. These include in situ waterlain sediments within tills, and clastic sills running along the till/substrate contact showing lift-off. These features indicate that the weight of the glacier lobes was, to a large extent, carried by pore-water pressure in subglacial sediments, and that subglacial shear and erosion were moderate. Thus, fast ice flow in the lobes is envisaged. The balance between glacier weight and pore-water pressure was probably maintained over time by the buoyancy effect of glaciers advancing into proglacial lakes. Subglacial lakes may have formed by capture of proglacial lakes during glacial advance. The combination of low-gradient ice and decoupled beds indicate that glacier advance and extent was largely controlled by lake levels and topographic thresholds. This is taken to indicate that steeper-gradient ice much farther upstream was providing the gravitational push. A presumably abrupt change in ice-surface profile is supported by the mapped distribution of glacial bedforms. The model presented herein potentially has wide applicability for large parts of northern Russia as the topographic setting and glacier advance in lakes across fine-grained low-permeable sediments provide very similar conditions.

We present multibeam swath bathymetric surveys of the major fjords surrounding the sub-Antarctic island of South Georgia to characterise the glacial geomorphology and to identify the relative timings and extent of past glacial advance and retreat. Bathymetry data revealed a range of glacial features including terminal, retreat and truncated moraines, deep (distal) outer and shallow (proximal) inner basins and cross shelf troughs. These provide evidence of glacial advance and retreat through several glacial cycles. A near consistent pattern of large scale submarine geomorphological features was observed in the different fjords suggesting a similar response of margins of the island ice cap to past climate forcing. A relative chronology based on the relationships between the submarine features with their radiocarbon and cosmogenic isotope dated terrestrial counterparts suggests that widely observed inner basin moraines date from the last major glacial advance or Last Glacial Maximum, while deep basin moraines may date from an earlier (pre-LGM) more extensive glaciation, which we speculate corresponds to MIS6. On the sides of the deep basins a series of truncated moraines show ice advance positions from preceding glacial periods. The cross shelf troughs, and mid-trough moraines are interpreted as the product of much more extensive glaciations that predate the fjord geomorphology mapped here, thus possibly older than MIS6. This hypothesis would suggest that South Georgia followed a glacial history similar to that of central Patagonia (46°S) where a series of Pleistocene glaciations (of MIS 20 and younger) extended beyond LGM limits, with the most extensive glacial advance occurring at c. 1.1 Ma.

Goriganga valley, which is located in the transition zone between the dry steppe of the Tibetan plateau in the north and the sub-humid Himalayan climate in the south, has preserved four events of glaciation with decreasing magnitude. The oldest Stage-I glaciation is represented by a ∼12.5 km long discontinuous diamictite ridge which terminates north of Rilkot (∼3100 m asl). The Stage-II glaciation is represented by sub-rounded and partially eroded lateral moraines and terminates around Martoli village (∼3240 m asl). The Stage-III and IV glacial moraines are sharp crested, unstable and terminate proximal to the present day glacier at ∼3640 m asl and ∼3740 m asl respectively. The Stage-II moraines have been optically dated between 25 ± 2 ka and 22 ± 1 ka implying that glacier expanded during the global Last Glacial Maximum (LGM). This is contrary to the suggestion that during Last Glacial maximum (LGM) glaciation was limited in extent due to weak Indian Summer Monsoon (ISM) in the monsoon dominated regions of the Himalaya. We ascribe the LGM glaciations to a combination of the lowered temperature and enhanced mid-latitude westerlies. Following the LGM glaciation, Goriganga valley experienced two major pulses of deglaciation. The older event is dated between 16 and 12 ka and is coeval with the initiation of the ISM whereas the younger events (10−8 ka) represent the early to mid-Holocene strengthened ISM. The Stage-III and IV glaciations which terminated proximal to the modern glacier are speculated to occur during the mid-Holocene and Little Ice Age (LIA) respectively.

The architecture of three Late Ordovician glacial valleys was studied in detail in the Tassili N'Ajjer (SE Algeria) outcrops. The valleys are oriented south–north, 2 to 5 km wide, and up to 250 m deep. The valley-fills revealed a very complex sedimentary architecture with significant lateral facies changes. Several glacial cycles induced the formation of Glacial Erosion Surfaces (GES) at the base and within the glacial valleys. The first type of GES shows a sharp and steep-angled contact without striations or associated syn-sedimentary deformation, suggesting that subglacial meltwater was the dominant erosive agent. A second type associated with the deformation of pre-glacial and syn-glacial sediment, suggests that ice was in contact with the valley floor. Four facies associations are proposed: FA1: subglacial tillite; FA2: Sub-to pro-glacial ice contact fans; FA3: Proglacial sub-aqueous gravity flows; and FA4: outwash fans. The stratigraphic architecture of three of the main valleys reveals a complex polyphase infill. At least two main cycles of ice-sheet advance and retreat can be interpreted from the sedimentary succession of each valley. Minor glacial cycles by ice oscillations also occur locally. GES morphology and the facies sequence suggest that the Iherir valleys were initiated by meltwater erosion in subglacial channels, whereas the Dider and Ouarsissen valleys were part of a large ice stream pathway. Above the valley-fill and the interfluves, a sand-rich unit of stacked lobes and channels is interpreted as submarine outwash fans deposited during final ice retreat. A glacial sequence found between two GES comprises fluvio-glacial or ice-contact fan deposits, fluvio-glacial eskers and tills. These sediments were deposited subglacially or at the glacier front during the ice maximum phase and/or the early ice retreat phase. During the ice retreat, interbedded subaqueous gravity flow deposits and diamictites filled the glacially cut topography as the sea invaded the valleys. Maximum ice retreat was associated with high water fluxes and sediment discharge, causing a sand-dominated outwash fan to prograde out over the valleys and interfluves. This outwash fan was supplied mainly by flood activity at the ice front, involving high-density sustained flows. The dominant facies consists of giant aggrading climbing dunes filling channels or constructing sandy lobes downstream.

Palaeoglacial reconstruction based on geomorphological mapping in the Pindari glacier valley, Alaknanda basin (Central Himalaya), has revealed five glacial stages with decreasing magnitude. The oldest and most extensive stage-I glaciation deposited sediments at ∼2200 masl (Khati village). The stage-II glaciation was around 7 km long and luminescence dated to 25 ± 2 ka, and has deposits at 3200 masl (Phurkia village). Stage-III glaciation is represented by degraded linear moraine ridges and is dated to 6 ± 1 ka and its remnants can be found around 3850 masl. A sharp crested crescentic moraine extending from around 3650 masl to 3900 masl is attributed to stage-IV glaciation and is dated to 3 ± 1 ka. Following this, there appears to have been a gradual recession in Pindari glacier as indicated by four sharp crested unconsolidated moraines (stage-V) on the valley floor which abuts the stage-IV moraine. We suggest that the stage-I glaciation occurred during the cool and wet Marine Isotopic Stage 3/4 (MIS-3/4), stage-II glaciations began with the onset of MIS-2, whereas the stage-III and IV glaciations occurred during the mid-to late Holocene (MIS-1). We speculate that the first sharp crested unconsolidated moraines around 3600 masl correspond to the later phase of the Little Ice Age (LIA). Historical data suggests that the remaining three ridges represent Pindari glacier snout positions at 1906, 1958 and 1965. We argue that the late Quaternary glaciations in the Pindar valley were modulated by changing insolation and summer monsoon intensity including the LIA, whereas the 20th century recessional trends can be attributed to post-LIA warming.

This work concerns the Late Quaternary evolution of the Astico Valley, with a focus on the relations between the glacial complexes hosted in the terminal valley tract and the piedmont fans. Three distinct glacial events are considered in this paper. Remote sensing, field survey, stratigraphic measurements and reconstructions, sand petrography, radiocarbon dating and pollen analyses allowed attribution of the last one to the LGM, a previous one probably to MIS 6 and the oldest to a generic glaciation of the Middle Pleistocene. Sand petrography analyses show that all these glacial deposits contain rock fragments that reached the Astico Valley through a transfluence of the Adige glacier. During LGM, this glacial stream entered the Astico Valley from the north through the Carbonare saddle (1075 m a.s.l.), as probably happened in previous major glaciations. The chronostratigraphy of two cores drilled near the towns of Vicenza and Villaverla shows that the outwash stream changed its route to the piedmont plain at the end of LGM, as a response to rapid glacial collapse. This switch led to the deactivation of the northwestern sector of the plain (Thiene fan) in favour of the southeastern one (Sandrigo fan). The lower and middle Astico Valley preserved significant evidence of even minor glacial fluctuations during the LGM in response to subtle climatic changes, namely an early glacial withdrawal at 23–24 cal ka, which may be difficult to distinguish in major Alpine glaciers.

Glacial geomorphological mapping from satellite imagery and field investigations provide the basis for a reconstructionof the extent and style of glaciation of the Shaluli Shan, a mountainous area ...

During various periods of Late Quaternary glaciation, small ice-sheets, -caps, -fields and valley glaciers, occupied the mountains and uplands of Far NE Russia (including the Verkhoyansk, Suntar-Khayata, and Chersky Mountains; the Kolyma-Anyuy and Koryak Highlands; and much of the Kamchatka and Chukchi Peninsulas). Here, the margins of former glaciers across this region are constrained through the comprehensive mapping of moraines from remote sensing data (Landsat 7 ETM+ satellite images; ASTER Global Digital Elevation Model (GDEM2); and Viewfinder Panorama DEM data). A total of 8414 moraines are mapped, and this record is integrated with a series of published age-estimates (n = 25), considered to chronologically-constrain former ice-margin positions. Geomorphological and chronological data are compiled in a Geographic Information System (GIS) to produce 'best estimate' reconstructions of ice extent during the global Last Glacial Maximum (gLGM) and, to a lesser degree, during earlier phases of glaciation. The data reveal that much of Far NE Russia (∼1,092,427 km 2 ) preserves a glaciated landscape (i.e. is bounded by moraines), but there is no evidence of former ice masses having extended more than 270 km beyond mountain centres (suggesting that, during the Late Quaternary, the region has not been occupied by extensive ice sheets). During the gLGM, specifically, glaciers occupied ∼253,000 km 2 , and rarely extended more than 50 km in length. During earlier (pre-gLGM) periods, glaciers were more extensive, though the timing of former glaciation, and the maximum Quaternary extent, appears to have been asynchronous across the region, and out-of-phase with ice-extent maxima elsewhere in the Northern Hemisphere. This glacial history is partly explained through consideration of climatic-forcing (particularly moisture-availability, solar insolation and albedo), though topographic-controls upon the former extent and dynamics of glaciers are also considered, as are topographic-controls upon moraine deposition and preservation. Ultimately, our ability to understand the glacial and climatic history of this region is restricted when the geomorphological-record alone is considered, particularly as directly-dated glacial deposits are few, and topographic and climatic controls upon the moraine record are difficult to distinguish. © 2012 Elsevier Ltd.

Mountain glaciers are highly sensitive to temperature and precipitation fluctuations and, thus, the deposits of glacier growth and retreat constrain climatic variables. The Dangzi valley, located on the northern slope of Queer Shan Mountain, eastern Tibetan Plateau, is influenced by Indian monsoon and has preserved four integrated sets of moraines and associated glacial sediments. Numerical ages are scarce in this area, even though the moraines have been investigated for decades. In this study, dating of the glacial tills and glaciofluvial deposits was undertaken using quartz optically stimulated luminescence (OSL). We conclude that: (1) OSL ages show good agreement with geomorphological features. The samples should have been well-bleached before deposition, otherwise it is rather impossibly that all the ages in the former three sets are overestimated to a similar degree due to poor beaching as the spatial and temporal dynamics vary within glaciated valley. (2) Mountain glaciers have reached the maximum extent at about 25-22 ka in Dangzi valley during the Last Glacial Maximum (LGM). Then the glaciers retreated several times and formed the last terminal moraine at about 16.5 ka, which may indicate the termination of LGM on the eastern Tibetan Plateau. (3) The age of DZ307 (54.0 +/- 4.7 ka) demonstrates that the glacial advance also occurred at Marine Isotope Stage (MIS) 3, and that the glacial advance was larger in MIS 3 than in LGM, which is in agreement with previous results in the adjacent Yingpu valley. (4) The glacial evolution during the LGM in the study area was possibly controlled by the temperature changes, which could response to the summer solar insolation in northern hemisphere. (C) 2012 Elsevier B.V. All rights reserved. Mountain glaciers are highly sensitive to temperature and precipitation fluctuations and, thus, the deposits of glacier growth and retreat constrain climatic variables. The Dangzi valley, located on the northern slope of Queer Shan Mountain, eastern Tibetan Plateau, is influenced by Indian monsoon and has preserved four integrated sets of moraines and associated glacial sediments. Numerical ages are scarce in this area, even though the moraines have been investigated for decades. In this study, dating of the glacial tills and glaciofluvial deposits was undertaken using quartz optically stimulated luminescence (OSL). We conclude that: (1) OSL ages show good agreement with geomorphological features. The samples should have been well-bleached before deposition, otherwise it is rather impossibly that all the ages in the former three sets are overestimated to a similar degree due to poor beaching as the spatial and temporal dynamics vary within glaciated valley. (2) Mountain glaciers have reached the maximum extent at about 25-22 ka in Dangzi valley during the Last Glacial Maximum (LGM). Then the glaciers retreated several times and formed the last terminal moraine at about 16.5 ka, which may indicate the termination of LGM on the eastern Tibetan Plateau. (3) The age of DZ307 (54.0 +/- 4.7 ka) demonstrates that the glacial advance also occurred at Marine Isotope Stage (MIS) 3, and that the glacial advance was larger in MIS 3 than in LGM, which is in agreement with previous results in the adjacent Yingpu valley. (4) The glacial evolution during the LGM in the study area was possibly controlled by the temperature changes, which could response to the summer solar insolation in northern hemisphere. (C) 2012 Elsevier B.V. All rights reserved.

The Quaternary glacial history of Tashkurgan valley, in the transition between the Pamir and Karakoram, in Xinjiang Province, China was examined using remote sensing, field mapping, geomorphic analysis of landforms and sediments, and 10Be terrestrial cosmogenic nuclide dating. Moraines were assigned to four glacial stages: 1) the Dabudaer glacial stage that dates to the penultimate glacial cycle and/or earlier, and may represent one or more glaciations; 2) the Tashkurgan glacial stage that dates to early last glacial, most likely Marine Oxygen Isotope Stage (MIS) 4; 3) the Hangdi glacial stage that dates to MIS 2, possibly early MIS 2; and 4) the Kuzigun glacial stage that dates to the MIS 2, possibly the global Last Glacial Maximum, and is younger than the Hangdi glacial stage. Younger moraines and rock glaciers are present at the heads of tributary valleys; but these were inaccessible because they are located close to politically sensitive borders with Pakistan, Afghanistan and Tajikistan. Glaciers during the Dabudaer glacial stage advanced into the central part of the Tashkurgan valley. During the Tashkurgan glacial stages, glaciers advanced several kilometers beyond the mouths of the tributary valleys into the Tashkurgan valley. Glaciers during the Hangdi and Kuzigun glacial stages advanced just beyond the mouths of the tributary valleys. Glaciation in this part of the Himalayan–Tibetan orogen is likely strongly controlled by northern hemisphere climate oscillations, although a monsoonal influence on glaciation cannot be ruled out entirely.

The Sea of the Hebrides is an island-studded region of complex bathymetry on the UK continental shelf, west of the Scottish mainland. An extensive area (2200 km2) of recently collected multibeam bathymetry data, combined with seismic reflection profiles reveal this part of the shelf to have been extensively modified by both glacial and modern processes. Our new geomorphological evidence strongly supports the contention that an ice stream drained ice from western Scotland and the Inner Hebrides towards the Barra Fan at the continental shelf break at the height of the last glaciation (Marine Isotope Stage 2–3). Convergent seabed glacial lineations and other subglacially streamlined features eroded in bedrock around the Islands of Canna and Rum preserve the direction of ice sheet movement, and strongly suggest the onset of ice streaming in a southwesterly direction on the continental shelf in the Sea of the Hebrides region. This fast-flow zone formed part of a larger convergent ice stream system draining much of western Scotland and the north of Ireland — the southern part of which has been postulated already. A number of rock basins, linear troughs and deeps west and south of Muck, kept sediment-free by the dominant modern tidal regime, are interpreted as being at least partly subglacial in origin. Similarly, a large complex of buried deeps between Eigg and Arisaig are interpreted as an overdeepened glacial drainage network. It is suggested that intense bedrock erosion by focused subglacial abrasion and subglacial meltwater discharge over multiple glacial advance and decay cycles led to significant modifications of the pre-Quaternary bedrock surface. Other features such as moraines are only found in shallower water (typically < 50 m), west of Canna, west of Rum and south of Skye. Their relative paucity indicates that the modern tidally dominated environment of the area may have removed much of the localised geomorphological evidence of offshore glacial limits within the Sea of the Hebrides, or alternatively that the ice sheet margin was floating and retreated predominantly by calving leaving little geomorphological evidence of its retreat.

Pine Island Glacier drains portions of the West Antarctic Ice Sheet into the Amundsen Sea. During the Last Glacial Maximum the glacier extended nearly 500 km from its present location onto the outer continental shelf. Unusually restricted sea-ice cover during the austral summer of 2010 allowed for a systematic multibeam swath-bathymetric and chirp sonar survey of the mid-shelf section of Pine Island Trough. The mapped glacial landforms reveal new information about the paleo-Pine Island Ice Stream's dynamic retreat from the mid-shelf area and confirm previous suggestion of a retreat in distinct steps. The periods of grounding line stability during the overall retreat phase are marked by sediment accumulations, i.e. grounding zone wedges. These wedges are here mapped in sufficient detail to characterize spatial dimensions and estimate the volume of deposited sediment. Considering a range of sediment flux rates from the paleo-Pine Island Ice Stream we estimate that the largest and most clearly defined grounding zone wedge, located at about 73°S in the surveyed area, took between 600 and 2000 years to form. The ice stream retreated landward of this wedge before 12.3 cal ka BP. The swath-bathymetric imagery of landforms in Pine Island Trough includes glacial features that suggest that retreat between periods of grounding line stability may be associated with episodes of ice shelf break-up. The depths of grounding line wedges decrease in a landward direction, from 740 to 670 m, and record elevation of the grounding line as it stepped landward. In all, the grounding line elevation varied by only ∼80 m over a distance of just over 100 km, implying a low ice sheet profile during retreat. Finally, we revisited seismic reflection profile NB9902, acquired along Pine Island Trough in 1999, in combination with the newly acquired swath-bathymetric imagery from 2010. Together these data show that the ice stream paused during its retreat to form grounding zone wedges at an area in central Pine Island Trough where a high in dipping bedrock strata exists and the glacial trough is narrow, forming a bathymetric “bottle neck”.

The Mt Giluwe shield volcano was the largest area glaciated in Papua New Guinea during the Pleistocene. Despite minimal cooling of the sea surface during the last glacial maximum, glaciers reached elevations as low as 3200 m. To investigate changes in the extent of ice through time we have re-mapped evidence for glaciation on the southwest flank of Mt Giluwe. We find that an ice cap has formed on the flanks of the mountain on at least three, and probably four, separate occasions. To constrain the ages of these glaciations we present 39 new cosmogenic 36 Cl exposure ages complemented by new radiocarbon dates. Direct dating of the moraines identifies that the maximum extent of glaciation on the mountain was not during the last glacial maximum as previously thought. In conjunction with existing potassium/argon and radiocarbon dating, we recognise four distinct glacial periods between 293–306 ka (Gogon Glaciation), 136–158 ka (Mengane Glaciation), centred at 62 ka (Komia Glaciation) and from >20.3–11.5 ka (Tongo Glaciation). The temperature difference relative to the present during the Tongo Glaciation is likely to be of the order of at least 5 °C which is a minimum difference for the previous glaciations. During the Tongo Glaciation, ice was briefly at its maximum for less than 1000 years, but stayed near maximum levels for nearly 4000 years, until about 15.4 ka. Over the next 4000 years there was more rapid retreat with ice free conditions by the early Holocene.

To help delineate the transition in pattern and timing of glaciation between two contrasting regions, Lahul to the south and Ladakh to the north, moraines in the Puga and Karzok valleys of Sanskrit in the Transhimalaya of northern India were mapped and dated using cosmogenic 10 Be. In Lahul, Late Quaternary glaciation was extensive with total valley glacial systems being >100 km in extent, whereas glaciation in Ladakh has been comparatively restricted, with glaciers advancing only ∼15 km from the contemporary glaciers during the last 200 ka. In the Puga valley, glaciers advanced >15 km at ∼129 ka and ∼10 km at ∼46 ka, ∼4.2 ka, and ∼0.6 ka. In the Karzok valley, glaciers advanced ∼1 km at ∼3.6 ka. Boulder exposure ages from a large moraine complex in Karzok indicate a glacial advance at ∼80 ka of ∼4 km from the present ice margin. The oldest moraine in Karzok is ∼311 ka, indicating that glaciers advanced >10 km from the present ice margin during or before marine isotope stage 9. The glacial chronology of the two valleys shows a lack of early Holocene glaciation and generally asynchronous glaciation between them. Moraines in the Puga and Karzok valleys broadly correlate with previous studies in the Zanskar Range but the paucity of data for many of the glacial stages across the Zanskar region makes the correlations tentative. The lack of early Holocene glaciation in the Puga and Karzok valleys is in stark contrast to many regions of the Himalaya, including Lahul, and the restricted glacial extent in Zanskar is more similar to the style of glaciation in Ladakh. The similarity between the glacial records in the Puga and Karzok study areas suggests that the transition to Lahul style glaciation is to the south of the Karzok valley, showing that this geographical transition is abrupt.

article i nfo Alluvial rivers of the eastern Puget lowland, a landscape shaped by scour and fill from the Cordilleran ice sheet, continue to respond to patterns of deposition and scour by the last-glacial-age ice sheet 18,000 years after deglaciation. Topography revealed by valley cross sections created from high resolution LIDAR digital elevation models shows that rivers are aggrading in valleys eroded by subglacial runoff and degrading in valleys incised by rivers post-glaciation. Slope-area analysis of river profiles shows that profile concavity varies systematically between river segments in the two valley contexts. Concavity indices (θ) in mountain headwaters (0.3b θb0.9) compare to those of many world rivers (0.2b θb1.0), but in the lowlands these indices differ between valleys created by subglacial fluvial erosion (5b θb45) and post-glacially incised river valleys that grade to base levels set by these relict glacial valleys or by post-glacial sea levels (1b θb7). Dramatic differences in river pattern, landforms, and dynamics occur in valleys having contrasting (aggrading vs. degrading) and incomplete responses to Pleistocene glaciation, creating discrete valley-scale hetero- geneities in fluvial process domains along and between rivers. These results point to the importance of valley- scale organization of alluvial process domains along and between rivers having profiles remaining in disequilibrium from Pleistocene glaciation. They also point to the potential usefulness of slope-area analysis of longitudinal profiles in distinguishing among different river valley process domains in lowland alluvial landscapes.

article Kveithola Trough, an E-W trending glacial trough in the NW Barents Sea, was surveyed for the first time during the EGLACOM cruise of R/V OGS-Explora in summer 2008. Swath bathymetry shows that the seafloor is characterized by E-W trending mega-scale glacial lineations (MSGL) that record a fast flowing ice stream draining the Svalbard/Barents Sea Ice Sheet (SBIS) during the Last Glacial Maximum (LGM). MSGL are overprinted by transverse sediment ridges about 15 km apart which give rise to a staircase axial profile of the trough. Such transverse ridges are interpreted to be grounding-zone wedges (GZWs) formed by deposition of subglacial till during episodic ice stream retreat. Sub-bottom (CHIRP) and multi-channel reflection seismic data show that the present-day morphology is largely inherited from the palaeo-seafloor topography at the time of deposition of the transverse ridges, overlain by a draping glaciomarine unit which in places is over 15 m thick. Our data allow the reconstruction of depositional processes which accompanied deglaciation of the Spitsbergen Bank area. The sedimentary drape deposited on top of the GZWs is suggested to have accumulated at a very high rate, (on average in the order of 1-1.5 m ka �1

This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers the period from the Last Glacial Maximum (LGM, 18–22 cal ka BP) into the Holocene. It records the history of a shelf-based glaciation with ice flowing eastward along the coast as well as two local valley glacier advances from the south during the Holocene. With ice on the coastal plain during the LGM, glaciolacustrine basins formed in marginal positions and in ice-dammed valleys to the south into the mountainous area of Peary Land. With the break-up of shelf-based ice there was a gradual marine inundation at which the marine limit formed at ∼45 m a.s.l. This initial early Holocene ice advance from the south formed prominent valley mouth moraines, especially in Sifs valley. Here, both glaciolacustrine and marine sediments were remoulded and/or dislocated as thrust blocks into a moraine ridge spanning more than 1 km in width and >60 m in height. Radiocarbon ages of sediments incorporated in this moraine, as well as from on-lapping sediments, suggest that the moraine formed between 9.6 and 6.3 cal ka BP. Based on 14 C dating results, the youngest ice advance phase can be narrowed down to 14 C ages between ∼5.5–5.0 cal ka BP. The recorded ice advances took place during the Holocene Thermal Maximum (HTM) for North Greenland, the last one close to the beginning of the Neoglacial cooling. During the HTM we have recorded a period of ∼2500 years during which the north coast of Greenland – as opposed to today – experienced an absence to very restricted occurrence of land-fast or multi-year sea ice. This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose that this lead to enhanced precipitation in the near-coastal areas which, coupled to documented HTM cold reversals, caused a lowered glaciation limit, and led to a positive mass balance and subsequent ice advance.

In almost all former and presently glaciated areas of the world, glaciers have modified or even transformed pre-glacial terrain during the many cold stages of the Pleistocene. In consequence, the early stages in the development of glacial landscapes have been overprinted or erased by later phases of erosion. The Sudetes in central Europe provide exceptional opportunities to examine the inception of glacial erosion. Evidence of a long geomorphic evolution before glaciation, with the development of etch surfaces, deep weathering covers and the preservation of Neogene kaolinitic sediments, provides a direct analogue to other lowland crystalline terrains as existed immediately prior to Pleistocene glaciation. Large granite intrusions exist in the Sudetes and its Foreland that support hills that range in size from small tors to large domes. These terrains experienced only thin ice cover for short periods when the Scandinavian ice sheet reached its Pleistocene maximum limits in Marine Isotope Stage (MIS) 12 (Elsterian) at 440–430 ka and MIS 8 (Early Saalian) at 250–240 ka. In each of four study areas beyond, at and within the limits of glaciation we have mapped Glacial Erosion Indicators, glacial landform assemblages that indicate progressive glacial modification of the pre-glacial granite terrain. We find that glacial erosion increases with distance from the ice margin, due to greater ice thickness and longer ice cover, but has had only limited impact. On hills, regolith was stripped by moving ice, tors were demolished, and blocks were entrained. However, indicators of more advanced glacial erosion, such as lee-side cliffs and glacial streamlining, are absent, even from granite domes that lay beneath ~ 500 m of ice. The survival of tors beneath ice cover and the removal of tor superstructure by glacial erosion are confirmed. The presence of glacially-modified tors in areas covered only by Elsterian ice implies that the tors existed before 440 ka. Moreover, the contrast between blockfield-covered slopes found above Elsterian and Saalian glacial trimlines on summits of granite, gabbro and basalt hills in the Sudetic Foreland and glacially-stripped surfaces at lower elevations implies only limited regeneration of blockfields since 430 and 240 ka. The first stages of roche moutonnee formation are recognised in the exhumation of tor stumps but development of lee-side steps remains very limited. Granite domes retain a pre-glacial morphology and local examples of hill asymmetry are determined by structural, rather than glaciological controls. Development of roches moutonnees and asymmetric and streamlined hills by glacial erosion has not occurred in the Sudetes despite the passage of largely warm-based ice sheets 80–500 m thick that persisted for 5–20 ka.

New Zealand glaciers reached their last glacial maximum position at or before ~ 25 ka, and, as early as 23 ka, commenced a slow and continual retreat. New cosmogenic exposure ages and field mapping from the Rakaia Valley in the South Island suggest that extensive ice survived well into the latter half of the Last Glacial–Interglacial Transition (18–11 ka), with the post-15 ka period inferred to have near Holocene climate conditions based on ecological proxy data. By as late as ~ 15.5 ka, glacier termini had retreated as little as 5–10 km from glacial maximum positions. Numerous minor ice still-stand positions and oscillations are recognized, but the record specifically excludes evidence for either a major climatic amelioration at ~ 15–16 ka or a significant glacial re-advance during the Antarctic Cold Reversal (ACR) or the Younger Dryas (YD). We conclude that the currently widespread interpretation of an episodic New Zealand glacial record since the LGM is an artifact of valley-dependent retreat processes. Pro-glacial lake formation and local site conditions combined to give an apparent, but misleading, picture of glacial retreat punctuated by major, climatically driven, re-advances. Copyright © 2010 Elsevier B.V. All rights reserved.

The Quaternary glaciation of Gurla Mandhata (Naimona’nyi), an impressive, isolated dome-shaped massif situated in a remote region of southern Tibet, was examined using glacial geomorphic methods and dated using 10 Be terrestrial cosmogenic nuclides. The oldest moraines, representing an expanded ice cap that stretched ∼ 5 km into the foreland of the Gurla Mandhata massif, likely formed during marine isotope stage (MIS) 10 or an earlier glacial cycle. Another glacial expansion of coalescing piedmont type occurred during the early part of the last glacial cycle or the penultimate glacial cycle, after which glaciers became restricted to entrenched valley types. Impressive latero-frontal moraines at the mouths of most valleys date to the early part of the last glacial cycle and MIS 3. A succession of six sets of moraines within the valleys and up to the contemporary glaciers show that glaciers advanced during the Lateglacial, Early Holocene, Neoglacial and possibly Little Ice Age. The change of style of glaciation throughout the latter part of the Quaternary, from expanded ice caps to deeply entrenched valley glaciers, might reflect: (1) climatic controls with reduced moisture supply to the region over time; and/or (2) tectonic controls reflecting increase basin subsidence due to detachment faulting and enhanced valley incision.

The Muzart River originates on the southeastern slope of Tumur Peak, the largest center of modern glaciation in the Tianshan Range. Glacial landforms and sediments indicate that there are four major Quaternary glaciations in this drainage. The glacial landforms contain considerable information about the changes of the ancient glaciers. Dating the landforms allows the temporal and spatial variations of the ancient glaciers in this valley to be understood and provides essential information in reconstructing the paleoenvironment in this region. Electron spin resonance (ESR) dating of a well-exposed section, the multiple end moraines of the Pochengzi glaciation (the third set of moraines), and the local outwash and fluvial sediments on the Kezibulake glacial plain (the fourth set of moraines) was carried out using germanium (Ge) centers in the glacial quartz grains, which are sensitive to both sunlight and grinding. Eleven depositional ages have been determined. Based on the dating results, the principle of superposition and the glaciations pattern reported in the adjacent valley, the Pochengzi end moraines were determined to be deposited during the major glacial intervals that are equivalent in age to marine oxygen isotope stages (MIS) 2, mid-MIS 3 and MIS 4 and the Kezibulake glacial deposits were determined to be equivalent in age to MIS 6. Furthermore, the Tugaibieliqi end moraine (the second set of moraines) was deposited during the Neoglaciation (a cold period between 3 and 4 ka) and the 3–4 end moraines located at the terminuses of the modern glacier were deposited during the Little Ice Age. The ages of the Pochengzi glacial deposits can be subdivided into three clusters, they are 13.6–25.3 ka, 39.5–40.4 ka and 64.2–71.7 ka, respectively. The largest local last glacial maximum (LGM L ) occurred during MIS 4 rather than the global Last Glacial Maximum (LGM G ) of MIS 2. Furthermore, a glacier that is slightly larger than that of MIS 2 developed in this drainage during mid-MIS 3. The ancient Muzart glaciers were compound valley glaciers during the Neoglaciation, MIS 2 and mid-MIS 3, and piedmont glaciers during MIS 4 and MIS 6.

Southeastern Tibet is the type area for monsoonal maritime glaciers in the Qinghai–Tibet Plateau with more than 4000 mountain glaciers covering an area of approximately 8000 km 2 . Based on moraines in the Boduizangbo River Valley, glacial advances have been recognized for the Guxiang, Baiyu, and Yuren Glaciations. Cosmogenic radionuclide surface exposure, ESR, and radiocarbon dating methods are used to estimate moraine ages. The dates suggest that glacial advances occurred during MIS-6, MIS-2 and MIS-1. Moraines of possible MIS-4 or MIS-3 age are also present, but have not yet been dated. During the Guxiang Glaciation, glaciers converged in the Boduizangbo Valley and formed a glacier approximately 100 km long, reaching the Parlongzangbo River Valley. During the Baiyu Glaciation the glacier was about 80 km long, yet did not reach the main valley of the Parlongzangbo River. During the Yuren Glaciation, glaciers advanced only within tributary valleys feeding the Boduizangbo River. Based on glacier extent, reconstructed equilibrium line altitudes during the Guxiang and Baiyu Glaciations were approximately 800 m and 600 m lower, respectively than at present. Mean annual air temperatures were depressed by approximately 6.6–7.8 � C compared to present values, estimating a 40% decrease in precipitation during

Valley glaciers have been well studied in the northwestern Venezuelan Andes over the last 20-year period with most sourcing reconstructions limited to the Last Glacial Maximum (LGM) and confined to the mapping of moraine positions and the detailed analysis of pedostratigraphic sequences reaching back into the Middle Wisconsinan (Weichselian) Glaciation. Using bedding macrofeatures, fabric analysis (magnetic azimuths) with mirror images, clast inclination and microtextural evidence determined with the FE-SEM (Field Emission Scanning Electron Microscopy) and EDS (Energy Dispersive Spectroscopy), and micromorphology of the PED5 composite section of Early to Late Merida age was analyzed to reconstruct the till succession and glacial dynamics. The fabric is used to reconstruct the build-up of valley ice in the lower Mucunuque Valley, the icecap spreading over the upper catchments of neighbouring drainage basins toward the headwaters of the Mucuchache Valley over a time frame estimated to be

Low-order alpine glacial valleys on Earth commonly have a characteristic spacing of 1–3 km. Here we develop analytic and numerical solutions of a coupled numerical model for alpine glacial flow and subglacial bedrock erosion to quantitatively determine the controls on glacial valley spacing assuming an initially-undissected landscape, an initially-fluvially-dissected landscape, and an initially-cratered landscape. The characteristic spacing of glacial valleys produced by the model is controlled by a competition between the thickening of ice in incipient glacial valleys, which acts to enhance flow and valley deepening, and viscous/sidewall drag, which acts to limit flow and deepening. The glacial valley spacing that represents the best compromise between these two competing effects is found to be a function of valley slope, the threshold basal shear stress for ice motion, the effective ice viscosity, a bed-friction parameter, and gravity. This model framework provides the preliminary basis for understanding the relative spacing of glacial valleys on Earth and Mars. On Mars, montane glacial valleys have widths and spacings that are approximately 10–20 times larger than those on Earth. Model results suggest that this difference is predominantly a consequence of lower bed slopes and larger temperature-controlled ice viscosities of glacial ice on Mars compared to Earth.