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The glacial trough is a common glacier erosion landscape, which plays an important role in the study of glacier erosion processes. In a sharp contrast with the developing river, which is generally meandering, the developing glacial trough is usually wide and straight. Is the straightness of the glacial trough just the special phenomenon of some areas or a universal feature? What controls the straightness of the glacial trough? Until now, these issues have not been studied yet. In this paper, we conduct systematic numerical models of the glacier erosion and simulate the erosion evolution process of the glacial trough. Numerical simulations show that: (1) while the meandering glacier is eroding deeper to form the U-shaped cross section, the glacier is eroding laterally. The erosion rate of the ice-facing slope is bigger than that of the back-slope. (2) The smaller (bigger) the slope is, the smaller (bigger) the glacier erosion intensity is. (3) The smaller (bigger) the ice discharge is, the smaller (bigger) the glacier erosion intensity is. In the glacier erosion process, the erosion rate of the ice-facing slope is always greater than that of the back-slope. Therefore, the glacial trough always develops into more straight form. This paper comes to the conclusion that the shape evolution of the glacial trough is controlled mainly by the erosion mechanism of the glacier. Thereby, the glacial trough prefers straight geometry.

Steep U-shaped valleys produced by glaciation are commonly eroded by rockfall. In this study we investigate modern and long-term (power law predicted) rates of rock wall retreat in a deglaciated valley. Our emphasis is on the 5.2 km2 calcareous cliffs covering in the Lauterbrunnen Valley, Switzerland. Terrestrial laser scans were collected during nine field campaigns over 18 months to provide a continuous coverage of most of the valley walls. Results indicate a total of 122 rockfalls with volumes ranging between 0.06 ± 0.01 and 119.34 ± 1.07 m3. Different size groups of rockfall events were correlated with environmental factors (e.g., freeze-thaw cycles/temperature, precipitation, and seismicity) using a linear regression with variable lag times of 0–6 months. The highest correlation factor (r = 0.6, P = 0.08, 90% significance level) is observed for freeze-thaw cycles and rockfall events smaller than 1 m3 with a 2 month delay between temperature extremes and rockfall. Frequency-magnitude relationships for rockfall events were calculated to predict less frequent larger rockfall events that did not occur during the observation period. A Monte Carlo analysis was applied to the frequency-magnitude relationship to evaluate the sensitivity of results to their stochastic nature. An average power law exponent of 1.71 ± 0.09 was calculated using linear regression. The calculated exponents are similar to other studies in calcareous rock settings conducted over different observation durations. Finally, we determine an average total eroded volume of 2.0−0.01+0.6⋅103 m3/yr and a corresponding long-term (power law predicted) cliff retreat rate of 0.39−0.02±0.12mm/yr.

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.

Detailed field mapping of glacial and paraglacial landforms and optical dating from these landforms are used to reconstruct the early Holocene glaciation in the semi-arid region of Miyar basin, Lahaul Himalaya. The study identifies three stages of glaciation, of decreasing magnitude and termed, from oldest to youngest, the Miyar stage (MR-I), Khanjar stage (KH-II), and Menthosa advance (M-III). The oldest glacial stage (MR-I) has been established on the basis of detailed geomorphological evidence such as U-shaped valley morphology, trimlines, and truncated spurs. It is speculated to be older than the global Last Glacial Maximum (gLGM) based on the magnitude of ΔELA (Equilibrium-Line Altitude, 606m). No evidence of glacier expansion recorded from the basin correlates with the period of the gLGM. The second stage (KH-II) is well represented by extensive depositional features such as lateral and terminal moraines, drumlins, and lacustrine fills that have been constrained within 10 ± 1 to 6.6 ± 1.0 ka (Optically stimulated luminescence—OSL—ages), dating it to the early Holocene advance following the Younger Dryas cooling event. Exceptionally young glacial records of expansion are limited within a few hundred meters of the present termini of tributary glaciers and correlates with the 18th-century cooling event. Records of this glacial advance, termed the Menthosa advance, are clearly noticed in some tributary valleys.

Southern South America contains a glacial geomorphological record that spans the past million years and has the potential to provide palaeoclimate information for several glacial periods in Earth's history. In central Patagonia, two major outlet glaciers of the former Patagonian Ice Sheet carved deep basins ∼50 km wide and extending over 100 km into the Andean plain east of the mountain front. A succession of nested glacial moraines offers the possibility of determining when the ice lobes advanced and whether such advances occurred synchronously. The existing chronology, which was obtained using different methods in each valley, indicates the penultimate moraines differ in age by a full glacial cycle. Here, we test this hypothesis further using a uniform methodology that combines cosmogenic nuclide ages from moraine boulders, moraine cobbles and outwash cobbles. 10 Be concentrations in eighteen outwash cobbles from the Moreno outwash terrace in the Lago Buenos Aires valley yield surface exposure ages of 169–269 ka. We find 10 Be inheritance is low and therefore use the oldest surface cobbles to date the deposit at 260–270 ka, which is indistinguishable from the age obtained in the neighbouring Lago Pueyrredon valley. This suggests a regionally significant glaciation during Marine Isotope Stage 8, and broad interhemispheric synchrony of glacial maxima during the mid to late Pleistocene. Finally, we find the dated outwash terrace is 70–100 ka older than the associated moraines. On the basis of geomorphological observations, we suggest this difference can be explained by exhumation of moraine boulders.

The glacial morphology of southern South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. Here we present the first geomorphological record for the Sierra Baguales Mountain Range (SBMR), forming the eastern foothills of the Southern Patagonian Andes 200 km from the Pacific coast. This area is topographically isolated from the Southern Patagonian Ice Field (SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Andean uplift, which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum (LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower elevations. This can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26 m Equilibrium Line Altitude (ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio (AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography.

The mountains of the Mediterranean world are now largely ice free, but many were repeatedly glaciated during the Quaternary ice age. This created spectacular glaciated landscapes with a rich array of glacial deposits and landforms. The glacial and glacio-fluvial records are often very well preserved and our understanding of the timing of Quaternary glaciation has very recently been transformed through the application of dating methods utilizing uranium-series and cosmogenic isotopes. Glacial records from the Mediterranean now boast some of the most robust chronologies for mountain glaciation anywhere in the world – they represent a unique archive of Quaternary environmental change of global significance. The southerly latitude and relatively small size of Mediterranean glaciers rendered them especially sensitive to Pleistocene and Holocene climate changes. This volume brings together the leading researchers and the latest research on Mediterranean glaciation. Several papers also explore glacier behaviour in the Holocene – including those glaciers of southernmost Europe at risk of disappearing this century.

The Quaternary ice age in New Zealand has similarities to and contrasts with glacial events in the Northern Hemisphere. During the Last Glacial Cycle, the largest glacial advance in New Zealand was 67–62,000 years ago, and so not during the conventional global Last Glacial Maximum (gLGM). In New Zealand glacials were characterised by alpine glacier expansion, mainly in South Island. In central North Island there were small glaciers, periglacial activity and large expanses of herbfield and shrubland. Tall podocarp-broadleaf forest retreated to Northland. The gLGM in New Zealand occurred 32–26,000 years ago, at least 12,000 years before the ice volume reached its maximum in the Northern Hemisphere, and by the time that occurred (19–18,000 years ago) New Zealand glaciers had retreated and almost disappeared from lower valleys.

In this study, a modelling approach was used to investigate the cause of the diversion of erratic boulders from Mont Blanc and southern Valais by the Valais Glacier to the Solothurn lobe during the Last Glacial Maximum (LGM). Using the Parallel Ice Sheet Model, we simulated the ice flow field during the LGM, and analyzed the trajectories taken by erratic boulders from areas with characteristic lithologies. The main difficulty in this exercise laid with the large uncertainties affecting the paleo climate forcing required as input for the surface mass-balance model. In order to mimic the prevailing climate conditions during the LGM, we applied different temperature offsets and regional precipitation corrections to present-day climate data, and selected the parametrizations, which yielded the best match between the modelled ice extent and the geomorphologically-based ice-margin reconstruction. After running a range of simulations with varying parameters, our results showed that only one parametrization allowed boulders to be diverted to the Solothurn lobe during the LGM. This precipitation pattern supports the existing theory of preferential southwesterly advection of moisture to the alps during the LGM, but also indicates strongly enhanced precipitation over the Mont Blanc massif and enhanced cooling over the Jura Mountains., Journal of Glaciology, 63 (239), ISSN:0022-1430, ISSN:1727-5652

The inland valleys of New Zealand’s South Island were heavily glaciated during the last glacial cycle. Subsequent fluvial incision has eroded out glacial deposits from the valleys in many locations, making it difficult to reconstruct glacial dynamics and chronology. The Brabazon and Butler Downs lie in a fault-controlled intra-montaine basin that has been largely protected from fluvial erosion and the area contains extensive evidence for multiple glacial margins. This paper presents a detailed glacial geomorphology map of the Brabazon and Butler Downs at a scale of 1:20,000. Glacial landforms have been mapped and subdivided into three main zones: an upper zone distinguished by a flight of kame terraces, a middle zone containing kettles and meltwater channels, and a lower zone of lateral moraines. The new map provides insight into former glacial environments in the region and provides a related framework for future paleoclimate reconstructions.

In this article, we present a map of the glacial geomorphology of the Altai andWestern Sayan Mountains, covering an area of almost 600,000 km2. Although numerous studies provide evidence for restricted Pleistocene glaciations in this area, others have hypothesized the past existence of an extensive ice sheet. To provide a framework for accurate glacial reconstructions of the Altai and Western Sayan Mountains, we present a map at a scale of 1:1,000,000 based on a mapping from 30 m resolution ASTER DEM and 15 m/30 mresolution Landsat ETM+ satellite imagery. Four landform classes have been mapped: marginal moraines, glacial lineations, hummocky terrain, and glacial valleys. Our mapping reveals an abundance of glacial erosional and depositional landforms. The distribution of these glacial landforms indicates that the Altai and Western Sayan Mountains have experienced predominantly alpine-style glaciations, with some small ice caps centred on the higher mountain peaks. Large marginal moraine complexes mark glacial advances in intermontane basins. By tracing the outer limits of present-day glaciers, glacial valleys, and moraines, we estimate that the past glacier coverage have totalled to 65,000 km2 (10.9% of the mapped area), whereas present-day glacier coverage totals only 1300 km2 (0.2% of the mapped area). This demonstrates the usefulness of remote sensing techniques for mapping the glacial geomorphology in remote mountain areas and for quantifying the past glacier dimensions. The glacial geomorphological map presented here will be used for further detailed reconstructions of the paleoglaciology and paleoclimate of the region. Central Asia Paleoglaciology Project (CAPP)

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.

Mars is the only planet other than Earth in the Solar System that has a preserved nonpolar geological record of glaciation on its surface. Nonpolar ice deposits on Mars have been linked to variations in spin-axis obliquity that cause mobilization of polar ice and redeposition at lower latitudes, forming ice-rich and glacial deposits. Remnant nonpolar glacial deposits are found across the northern mid-latitudes where surface ice is not currently stable, implying that different climatic conditions existed on Mars in the past. Individual glacial deposits are often too small to date reliably using impact crater size-frequency data. We describe a novel approach that allows us to derive new information about when glaciation occurred in broad areas of the northern mid-latitudes. In this region we have classified (1) craters that superpose preexisting glacial deposits and were modified by later accumulation (and therefore formed during an epoch when glaciation was occurring), and (2) craters that are superposed on glacial deposits but are themselves unmodified by ice accumulation (and thus post-date significant glaciation). The sparse population of post-glacial craters reveals that the last period of extensive ice deposition of this type in this latitude band was recent (Late Amazonian). The substantial number of craters formed during the recurring glacial periods implies that northern mid-latitude glaciation was a long-lived recurring process, occurring over a period of at least ∼600 m.y. On the basis of Mars atmospheric general circulation models, these results are consistent with higher obliquity being common in the past, with recurring periods of obliquity exceeding the 25° axial tilt of Mars today. These observations support the statistical prediction of J. Laskar and colleagues that the median obliquity during the Amazonian was ∼35°–40°.

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.

The glacial history of the Tons River Valley reveals significant changes in the glacier extent during the late Quaternary driven by regional and global climatic changes. The successions of moraines in glaciated valley of the upper Tons River, Garhwal Himalaya, provide evidence of at least five glacial advances during the late Quaternary Period. This study discusses about the synchronicity of Himalayan glaciers and comparison between results of Optically Stimulated Luminescence (OSL) and Cosmogenic Radio Nuclide (CRN 10Be) dates. The OSL dates of moraine sediments deposited by glacier in the upper Tons valley show parallelism with the ages deduced from the CRN of 10Be by Scherler et al. in the same area. The five episodes of glacier advances are dated at 20 ± 3, 16 ± 2, 8 ± 1.2, 6 ± 0.7 and 3 ± 0.6 kyr (between Marine Isotope Stages (MISs) I and II). Two of the more extensive phases of glaciation were during the early and later parts of MIS II, which attributed to the lower temperature and enhanced the mid-latitude westerlies. During the periods between 20 ± 3 kyr and present day, the glacier lost ~47 km2 (33%) area, 0.88 × 1010 m3 water equivalent (w.e.) volume with the rate of 0.44 × 106 m3 w.e./yr, which is close to the current melting rates of Central Himalayan glaciers. The estimation of equilibrium line altitude (ELA) using these dates and geomorphic data suggests a vertical shift of ~451 m for Jaundhar Glacier and ~598 m for Bandarpunch Glacier since 20 kyr. The results from Tons valley glaciation show synchronicity with the records of glacial advancements from the other Himalayan glacier valleys. These data allow testing of two widely used dating techniques and importance of global climate change and monsoon influence on glaciation in the Himalaya.

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.

It is highly debated whether glacial advances on the Qinghai–Tibetan Plateau (QTP) occurred as a response to temperature cooling, or whether they were forced by an increase in moisture brought by the intensive Indian summer monsoon. We here report a case study investigating this issue. Multiple moraine series in the Yingpu Valley, Queer Shan ranges of the Hengduan Mountains, and eastern QTP, provide an excellent archive for examining the timing and trigger mechanism of glacier fluctuations. Twenty-seven optically stimulated luminescence (OSL) samples of glacial sediments were collected from this valley. The quartz OSL ages show that the moraine series of Y-1, I, M and O were formed during the Late Holocene, Late Glacial, the global Last Glacial Maximum (LGM) and Marine Oxygen Isotope Stage (MIS) 3 (likely mid-MIS-3). The youngest Y-2 moraines probably formed during the Little Ice Age (LIA). The oldest H moraines formed before MIS-3. We found that glacial advances during the late Quaternary at the Yingpu Valley responded to cold stages or cold events rather than episodes of enhanced summer monsoon and moisture. As a result, glaciers in the monsoonal Hengduan Mountains were mainly triggered by changes in temperature. Millennial time scale temperature oscillations might have caused the multiple glacial advances.

The timing of terrace formation relative to the glacial–interglacial cycle and what factors control that timing, such as changes in climate and/or uplift, are controversial. Here we present a study of the terraces along the Yazheku River using electron spin resonance (ESR) dating and analysis of the sedimentary characteristics in order to establish the timing of terrace formation and to assess the forcing mechanisms that have been proposed. The Yazheku River flows in glacial trough leading from the Haizi Shan, on the eastern Tibetan Plateau. The range was uplifted during the Quaternary and repeatedly glaciated by ice caps. The four highest major terraces (T5, T4, T3, and T2) are the result of both climatic and tectonic influences. Strath terraces T5–T2 were created during Haizi Shan glacial expansions during MIS 16, 12, 6 and 3–4, respectively. The major aggradation phases of the four terraces occurred during the deglaciations at the ends of MIS 16, 12, 6, and 2. Down-cutting, which led to the generation of the four terraces, immediately followed the deposition of the T5–T2 gravel units. These incisions occurred during the transitions between MIS 16–15, MIS 12–11, MIS 6–5, and MIS 2–1.

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.

The paper is concerned with the structure of the Arctic shelf sediments in the Ob’ region in the Paleogene and Neogene, sampled from boreholes drilled on the Yamal Peninsula, in the lower reaches of the Pur and Taz Rivers. The specifics of Paleogene marine sedimentation in the central and northern West Siberian Plain are studied. The effect of abiotic (tectonic) factors on the completeness of the geologic record is considered as well as the effect of recent (Oligocene–Neogene) tectonic processes on topography and sedimentation. The borehole sections are compared with the main seismic sections of the Kara Sea and Lomonosov Ridge.

[1] Bedrock stresses induced through exhumation and tectonic processes play a key role in the topographic evolution of alpine valleys. Using a finite difference model combining the effects of tectonics, erosion, and long-term bedrock strength, we assess the development of near-surface in situ stresses and predict bedrock behavior in response to glacial erosion in an Alpine Valley (the Matter Valley, southern Switzerland). Initial stresses are derived from the regional tectonic history, which is characterized by ongoing transtensional or extensional strain throughout exhumation of the brittle crust. We find that bedrock stresses beneath glacial ice in an initial V-shaped topography are sufficient to induce localized extensional fracturing in a zone extending laterally 600 m from the valley axis. The limit of this zone is reflected in the landscape today by a valley “shoulder,” separating linear upper mountain slopes from the deep U-shaped inner valley. We propose that this extensional fracture development enhanced glacial quarrying between the valley shoulder and axis and identify a positive feedback where enhanced quarrying promoted valley incision, which in turn increased in situ stress concentrations near the valley floor, assisting erosion and further driving rapid U-shaped valley development. During interglacial periods, these stresses were relieved through brittle strain or topographic modification, and without significant erosion to reach more highly stressed bedrock, subsequent glaciation caused a reduction in differential stress and suppressed extensional fracturing. A combination of stress relief during interglacial periods, and increased ice accumulation rates in highly incised valleys, will reduce the likelihood of repeat enhanced erosion events.

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 late Quaternary glacial history of the Nun-Kun massif, located on the boundary between the Greater Himalaya and the Zanskar range in northwestern India, was reconstructed. On the basis of morphostratigraphy and 10Be dating of glacial landforms (moraines and glacial trimlines), five glacial stages were recognized and defined, namely: (i) the Achambur glacial stage dated to Marine Oxygen Isotope Stage 3 to 4 (38.7–62.7 ka); (ii) the Tongul glacial stage dated to the early part of the Lateglacial (16.7–17.4 ka); (iii) the Amantick glacial stage dated to the later part of the Lateglacial (14.3 ka, 11.7–12.4 ka); (iv) the Lomp glacial stage dated to the Little Ice Age; and (v) the Tanak glacial stage, which has the youngest moraines, probably dating to the last few decades or so. Present and former equilibrium-line altitudes (ELAs) were calculated using the standard area accumulation ratio method. The average present-day ELA of ∼4790 m above sea level in the Greater Himalaya is lower than those in the Ladakh and Zanskar ranges, namely 5380 and ∼5900 m a.s.l., respectively. The ELA in the Zanskar range is higher than in the Ladakh range, possibly due to the higher peaks in the Ladakh range that are able to more effectively capture and store snow and ice. ELA depressions decrease towards the Ladakh range (i.e. inner Plateau). Peat beds interbedded with aeolian deposits that cap the terminal moraine of Tarangoz Glacier suggest millennial-time-scale climate change throughout the Holocene, with soil formation times at c. 1.5, c. 3.4 and c. 5.2 ka, probably coinciding with Holocene abrupt climate change events. Given the style and timing of glaciation in the study area, it is likely that climate in the Nun-Kun region is linked to Northern Hemisphere climate oscillations with teleconnections via the mid-latitude westerlies.

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.

[1] Modern shelf bathymetry bordering the Gulf of Alaska exhibits shelf-crossing sea valleys that suggest focused pathways for ice flow during glacial conditions. Using an integrated seismic data set between the present Yakutat and Alsek Sea Valleys, we investigate the glacial stratigraphic record in order to improve our understanding of the regional glacial system during maximum glacial conditions. Our investigations reveal four glacial unconformities, of which, the latter two are overlain by sediment packages hundreds of meters thick. We suggest that these unconformities are indicative of ice advance phases during the Little Ice Age (LIA), the Last Glacial Maxima (LGM), and two pre-LGM advances with glacial retreat sequences preserved from the youngest two. The advances were dominated by ice expanse from the Malaspina Glacial system and Alsek River districts rather than the Hubbard Glacial system and only show distinctive morainal bank development near the shelf edge and near the mouth of, or within, modern bays, fjords, or river valleys. This observation strongly supports rapid and continuous retreat from glacial maxima conditions during climatic warming. All, except the inferred LIA sequence, transgress the shelf and exhibit concentrated erosion in overdeepened troughs, analogous to cross-shelf troughs similar to those observed on other high-latitude glaciated shelves. The two Alaskan troughs discussed here may be end-member examples of high-sediment flux systems due to the temperate glacial setting combined with an actively exhuming orogen.

33 páginas, 9 figuras.- Versión pre-print, [EN] The Aragón Valley glacier (Central Western Pyrenees) has been studied since the late nineteenth century and has become one of the best areas in the Pyrenees to study the occurrence of Pleistocene glaciations and the relationships between moraines and fluvial terraces. New morphological studies and absolute ages for moraines and fluvial terraces in the Aragón Valley allow a correlation with other Pyrenean glaciers and provide solid chronologies about the asynchroneity between global last glacial maximum (LGM) and the maximum ice extent (MIE). Six frontal arcs and three lateral morainic ridges were identified in the Villanúa basin terminal glacial complex. The main moraines (M1 and M2) correspond to two glacial stages (oxygen isotopic stages MIS 6 and MIS 4), dated at 171±22ka and 68±7ka, respectively. From a topographical point of view, moraine M1 appears to be linked to the 60m fluvioglacial terrace, dated in a tributary of the Aragón River at 263±21ka. The difference in age between M1 moraine and the 60m fluvioglacial terrace suggests that the latter belongs to an earlier glacial stage (MIS 8). Moraine M2 was clearly linked to the fluvioglacial 20m terrace. Other minor internal moraines were related to the 7-8m terrace. The dates obtained for the last glacial cycle (20-18ka) are similar to other chronologies for Mediterranean mountains, and confirm the occurrence of an early MIE in the Central Pyrenees that does not coincide with the global LGM. © 2012 Swedish Society for Anthropology and Geography., Support for this research was provided by the projects CALIBRE-LIMNOCAL (CGL2006-13327-C04-01) and GRACCIE-CONSOLIDER (CSD2007-00067), financed by the Spanish Inter-Ministry Commission of Science and Technology; and PIRINEOS ABRUPT (PM073/2007), financed by the Diputación General de Aragón. Additional funding was provided by the Spanish National Parks Agency through the project “Evolución climática y ambiental del Parque Nacional Picos de Europa desde el ultimo máximo glaciar” (ref. 53/2006), provided by the Spanish Ministry of Environment. The authors gratefully acknowledge Dr P.D. Hughes and an anonymous reviewer for their comments and suggestions, which significantly improve this paper.

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.

We report on 475 measurements of depth to ice-cemented ground in four high-elevation valleys of the Quartermain Mountains, McMurdo Dry Valleys, Antarctica. These valleys have pervasive ice-cemented ground, and the depth to ice-cemented ground and the ice composition may be indicators of climate change. In University Valley, the measured depth to ice-cemented ground ranges from 0–98 cm. There is an overall trend of increasing depth to ice-cemented ground with distance from a small glacier at the head of the valley, with a slope of 32 cm depth per kilometre along the valley floor. For Farnell Valley, the depth to ice-cemented ground is roughly constant (c. 30 cm) in the upper and central parts of the valley, but increases sharply as the valley descends into Beacon Valley. The two valleys north of University Valley also have extensive ice-cemented ground, with depths of 20–40 cm, but exhibit no clear patterns of ice depth with location. For all valleys there is a tendency for the variability in depth to ice-cemented ground at a site to increase with increasing depth to ice. Snow recurrence, solar insolation, and surface albedo may all be factors that cause site to site variations in these valleys.

Pietro Sternai : Now at: the Institut desSciences de laTerre d'Orléans - (ISTO), University of Orléans,France. Tel.: 33 631910242. E-mail addresses: pietro.sternai@univ-orleans.fr, pietro.sternai@erdw.ethz.ch; International audience; The present-day topography of the European Alps shows evidence of intense glacial reshaping. However, significant questions regarding Alpine landscape evolution during glaciations still persist. In this study, we focus on the Rhône valley (Swiss Alps), and use a numerical model to estimate patterns and magnitudes of glacial erosion. Comparing modeling results on a reconstructed pre-glacial topography and the present-day landforms, we find that the landscape response to glaciation is more complex than a simple "buzzsaw" mechanism (by which glacial erosion sets the height of mountain ranges) or increase of relief due to localized valley incision. Instead, glacial erosion propagates headward as the landforms evolve from a fluvial to a glacial state, leading to an initial increase of local relief followed by subsequent erosion at high elevations. It has also been proposed that the mid-Pleistocene climatic transition of glacial/interglacial oscillations from periods of 40 kyr (with symmetric shapes) to periods of 100 kyr (with asymmetric shapes) promoted glacial erosion within the Alps. Although this change of climate periodicity may have contributed to enhance glacial erosion, our results suggest that other factors such as an increase in rock uplift and/or progressive climate cooling are required to explain enhanced glacial carving at View the MathML source∼1Ma.

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 ...

Marl lakes are those accumulating fine-grained bottom sediments including at least 25 % CaCO3. Visually attractive examples have higher proportions of CaCO3, with crystallites precipitating in the water to give it a rich and opaque duck-egg blue colouration. Such lakes are largely limited to recently glaciated carbonate rock terrains. Most are also shallow, with much or all of the water column being in the photic zone. Little Limestone Lake (lat. 53°47′N, long. 99°19′W) is the finest example that the author has seen. It occupies a shallow glacial trough scoured in a plain of flat-lying cyclothem dolomites. It is ~12 km long, 1–5 km wide, and rarely >7 m deep. Including bordering wetlands, it occupies ~45 % of the area of an elongated, narrow topographic basin. Recharge is through impoverished boreal forest with little soil cover; it discharges chiefly as springs and seeps along and below the shore. Mean annual temperature is ~1 °C, and precipitation is ~475 mm/year. Springs in the surrounding region show groundwaters to be simple bicarbonate composition, with TDS = 230–300 mg/L. Grab sampling throughout the lake found its waters degassed to 125–135 mg/L. Little Limestone Lake is visually spectacular because it is almost entirely groundwater fed, with a ratio of recharge area to lake area that is low. In contrast, nearby lakes are regularly flushed by channelled surface storm water and thus cannot maintain high densities of crystallites in suspension. The lake became protected as a provincial park in June 2011.

The maximum glacial extent in the Central Pyrenees during the Last Glaciation is known to have occurred before the global Last Glacial Maximum, but the succession of cold events afterwards and their impact on the landscape are still relatively unknown. This study focuses on the environmental evolution in the upper valley of the Garonne River since the Last Glaciation. Geomorphological mapping allows analysis of the spatial distribution of inherited and current processes and landforms in the study area. The distribution of glacial records (moraines, till, erratic boulders, glacial thresholds) suggests the existence of four glacial stages, from the maximum expansion to the end of the glaciation. GIS modeling allows quantification of the Equilibrium Line Altitude, extent, thickness and volume of ice in each glacial stage. During the first stage, the Garonne glacier reached 460 m in the Loures-Barousse-Barbazan basin, where it formed a piedmont glacier 88 km from the head and extended over 960 km 2 . At a second stage of glacier stabilization during the deglaciation process, the valley glaciers were 12–23 km from the head until elevations of 1000–1850 m, covering an area of 157 km 2 . Glaciers during stage three remained isolated in the upper parts of the valley, at heights of 2050–2200 m and 2.6–4.5 km from the head, with a glacial surface of 16 km 2 . In stage four, cirque glaciers were formed between 2260 m and 2590 m, with a length of 0.4–2 km and a glacial area of 5.7 km 2 . Also, the wide range of periglacial, slope, nival and alluvial landforms existing in the formerly glaciated environments allows reconstruction of the post-glacial environmental dynamics in the upper Garonne basin. Today, the highest lands are organized following three elevation belts: subnival (1500–1900 m), nival (1900–2300 m) and periglacial/cryonival (2300–2800 m).

A detailed understanding of microbial ecology in different supraglacial habitats is important due to the unprecedented speed of glacier retreat. Differences in bacterial diversity and community structure between glacial snow and glacial soil on the Chongce Ice Cap were assessed using 454 pyrosequencing. Based on rarefaction curves, Chao1, ACE, and Shannon indices, we found that bacterial diversity in glacial snow was lower than that in glacial soil. Principal coordinate analysis (PCoA) and heatmap analysis indicated that there were major differences in bacterial communities between glacial snow and glacial soil. Most bacteria were different between the two habitats; however, there were some common bacteria shared between glacial snow and glacial soil. Some rare or functional bacterial resources were also present in the Chongce Ice Cap. These findings provide a preliminary understanding of the shifts in bacterial diversity and communities from glacial snow to glacial soil after the melting and inflow of glacial snow into glacial soil.

Cosmic-ray exposure (CRE) dating of moraines allow glacier fluctuations and past climate change reconstructions. In the French Alps, there is a lack of moraine dating for the Late Glacial/Holocene transition period. Here we present a chronology of glacier advances in the Upper Romanche valley (French Alps – Massif des Ecrins) based on 10 Be CRE dating. CRE ages of moraines of 13.0 ± 1.1 ka and 12.4 ± 1.5 ka provide evidence for two stages of glacial advance or standstill at the end of the Late Glacial. The CRE dating of a rock avalanche deposit at 12.2 ± 1.5 ka is attributed to post-glacial debuttressing and reveals rapid deglaciation at the end of the Late Glacial. A CRE age of 7.1 ± 0.7 ka of a second mass-wasting, whose triggering factor is unidentified so far, indicates that up to an altitude of 2300 m a.s.l., the valley was ice-free as of ∼7 kyr at the latest. The re-evaluation of 21 moraine 10 Be CRE ages from nine glacial valleys across the Alps shows multiple glacial advances occurring at the Late Glacial/Holocene transition. These results lead to a re-evaluation of the importance of cooling events during the Allerod and the Younger Dryas in the Alps.

The paper presents a glacial geomorphological map of landforms produced by different glaciers in East liddar during the past. The map has been created as the necessary precursor for an improved understanding of the glacial history of the region, and to strengthen a program of dating glacial limits in the region. The map was produced using Landsat TM, ASTER DEM, Google Earth™ imagery and field validation. The different landforms which were mapped include: lateral moraines, terminal moraines, proglacial lakes, palaeo-cirques, erratic boulders, outwash plains, whale backs, glacial grooves, rochee mountanee, drumlins, glacial striations, hanging valleys debris/talus cones, subglacial material. Glacial-Geomorphological features are very significant for palaeo-climatic reconstruction, showing variations, temporally and spatially. At the same time these landforms, which are also altered by processes prevailing during interglacial period, helps in geo-environment studies.

Covered karsts are classified according to the character of the cover (cryptokarst if the cover is impermeable and concealed karst if it is permeable), to the origin of cover deposits (locally deposited or transported there) and to the age of karstification (syngenetic if the depression in the cover and the form in the bedrock are of the same age and postgenetic if not). Covered karsts may develop in structural landforms (synclines, tectonic graben, horsts of various elevations) and in depressions formed by the powers shaping the surface, which could be of karstic origin (doline, ponor, polje, fengcong depressions and intermountain plains of fenglin karst) or of non-karstic origin (valley, abrasional platform and river terrace). The appearance and pattern of covered karst depend on the type of karst. When characterising pattern geosyncline or glaciokarst (folded-nappe structure), block mountains, platform, salt diapir, tundra, taiga, temperate, mediterranean and tropical covered karsts are distinguished. The geosyncline (glaciokarst) and block mountains karst types mainly occur under temperate climate, while the platform and salt diapir may appear on any climatic karst type. According to pattern, covered karst developed from allogenic karst (which can be recent allogenic, rejuvenating allogenic or semi-allogenic), nappe allogenic, horst, cirque, glacial trough, polje, karst hill, cueasta, tropical depression, polygonal, intermountain plain, petrified forest, platform and salt diapir covered karsts are identified. On the recent allogenic karst, in slope direction from the bordering non-karstic surface, cryptokarst, mixed and open karst zones are found. On the rejuvenating allogenic karst, in slope direction from the former terrain of sediment supply, open, mixed and buried karst zones follow each other. On the semi-allogenic karst, in lack of the accumulation of fluvial deposits, the cover sediment does not derive from the non-karstic terrain bordering the karst and is of continuous distribution. On the nappe allogenic karst, buried karst, cryptokarst (with karst windows), concealed karst and open karst zones occur. On horst covered karst, on the neighbouring blocks, concealed, crypto and buried karst terrains alternate (in patches or in continuous distribution). On the glacial trough covered karst, striped or striped-patchy patterns are typical. On the polje karst, continuous or zonal (so-called internal zonal) covered karst develops. On the karst hill covered karst, the patches of covered karst may coalesce, while on cueasta covered karst, the patches of covered karst are arranged in stripes parallel to the cuestas. The tropical depression covered karst and the polygonal covered karst show patchy distribution, while the intermountain plain covered karst is continuous, but can show internal zonation with crypto and concealed karst zones. No or poor zonation can be identified on the platform karst. The covered karst of salt diapir shows patches and develops on the cover uplifted by the rising salt diapir.

The Alps and the Alpine foreland have been shaped by repeated glaciations during Quaternary glacial-interglacial cycles. Extent, timing and impact on landscape evolution of these glaciations are, however, poorly constrained due to the fragmentary character of terrestrial archives. In this context, the sedimentary infills of subglacially eroded, ‘overdeepened’, basins may serve as important archives to complement the Quaternary stratigraphy over several glacial-interglacial cycles. In this thesis, the infills of deep subglacial basins in the Lower Glatt valley (N Switzerland) are explored to better constrain the Middle- to Late Pleistocene environmental change. Five drill cores gave direct insight into to the up to ~200 m thick valley fill at the study site and allowed for detailed analysis of sedimentary facies, age and architecture of the basin fills. A first focus is set on the sedimentology of coarse-grained diamicts with sorted interbeds overlying bedrock in the trough center, which mark the onset of deposition in many glacial bedrock troughs. Evidence from macro- and microsedimentology suggests that these sediments are emplaced subglacially and reflect deposition, reworking and deformation in response to repeated coupling and decoupling of the ice-bed interface promoted by high basal water pressures. Overlying these subglacial sediments, large volumes of sandy glacio-deltaic, fine-grained glacio-lacustrine and lacustrine sediments document sedimentation during glacier retreat from the basins. On these thick valley fill sequences the applicability and reliability of luminescence dating is investigated in a second step on the basis of experiments with several different luminescence signals, protocols and experiments to assess the signal stability. The valley fill of the Lower Glatt valley is then grouped into nine depositional cycles (Formations A-I), which are related to the Birrfeld Glaciation (~MIS2), the Beringen Glaciation (~MIS6), and up to three earlier Middle Pleistocene glaciations, tentatively correlated to the Hagenholz, Habsburg, and Mohlin Glaciations, according to the regional glaciation history. The complex bedrock geometry and valley fill architecture are shown to be the result of multiple erosion and infilling cycles and reflect the interplay of subglacial erosion, glacial to lacustrine infilling of overdeepened basins, and fluvial down-cutting and aggradation in the non-overdeepened valley fill. Evidence suggests that in the study area deep bedrock incision, and/or partial re-excavation, occurred mainly during the Beringen and Hagenholz Glaciation, while older structures may have existed. Together with the observation of minor, ‘inlaid’ glacial basins, dynamic changes in the magnitude and focus of subglacial erosion over time are documented.

The Western Massif of the Picos de Europa (latitude 43° N, longitude 4–5° W) includes some of the highest peaks in the Cantabrian Mountains. This massif was heavily glaciated during the Last Glaciation, though the post-glacial environmental evolution is still poorly understood. Using a complementary geomorphological and sedimentological approach, we have reconstructed the environmental events occurred in this massif since the last Pleistocene glaciation. The geomorphological distribution of glacial landforms suggests the occurrence of four main glacial stages: maximum glacial advance, glacial expansion after the maximum advance, Late Glacial and Little Ice Age. Moreover, a 5.4-m long sedimentary sequence was retrieved from the karstic depression of Belbín providing a continuous record of the paleoenvironmental conditions in this area since the Last Glaciation until nowadays. This section suggests that the maximum glacial expansion occurred at a minimum age of 37.2 ka cal BP, significantly prior to the global Last Glacial Maximum. Subsequently, periglacial processes prevailed in the mid lands of the massif until glaciers expanded between 22.5 and 18.7 ka cal BP. Following the melting of the glaciers, a shallow lake appeared in the Belbín depression. Lake sediments do not show evidence of a cold stage during the Late Glacial, when moraine systems formed at higher locations. The terrestrification of this lake started at 8 ka cal BP and the area turned into grassland. At 4.9 ka cal BP the existence of charcoal particles in the sediments of Belbín sequence reveals the onset of human occupation in the massif through the use of fire activity for grazing purposes. Finally, the presence of moraines inside the highest northern cirques shows evidence of the last glacial phase that occurred during the Little Ice Age cold event. Since then, the warming climate has led to the melting of these glaciers and periglacial processes prevail in the high lands of the massif., The authors acknowledge the support provided by the Picos de Europa National Park during the fieldwork developed between 2005 and 2011. M. Oliva acknowledges the AXA Research Fund for funding his research activities. Cristina García-Hernández is a grant holder of the FPU Program (Spanish MECD)

The paper presents a glacial geomorphological map of landforms produced by different glaciers in west liddar during the past. The map has been created as the necessary precursor for an improved understanding of the glacial history of the region, and to strengthen a programme of dating glacial limits in the region. The map was produced using Landsat TM, ASTER DEM, Google Earth TM imagery and field validation. The different landforms which were mapped include: lateral moraines, terminal moraines, proglacial lakes, palaeo-cirques, erratic boulders, outwash plains, whale backs, glacial grooves, rochee mountanee, drumlins, glacial striations, hanging valleys debris/talus cones, subglacial material. Glacio-Geomorphological features are very significant for palaeo-climatic reconstruction, showing variations, temporally and spatially. At the same time these landforms, which are also altered by processes prevailing during interglacial period, helps in geo-environment studies.

Traditionally regarded as a relict permafrost and periglacial landscape that lay beyond the limits of Pleistocene glaciation, the granite uplands of northern Dartmoor in south-west England in fact contain geomorphological evidence for the former existence of a plateau ice cap, making the area the location of the southernmost independent glacier mass in the British Isles. In addition to weakly U-shaped valleys, the most prominent evidence comprises arcuate and linear bouldery ridges and hummocky valley floor drift, which are interpreted as latero-frontal moraines deposited by the outlet glacier lobes of a plateau ice cap. Inset sequences of these depositional landforms, in association with meltwater channels, demarcate the receding margins of the glacier lobes. A numerical model of ice cap development shows that a predominantly thin plateau icefield type glaciation is required in order to produce significant ice flow into surrounding valleys. The highest and most extensive plateau areas were occupied by ice for the longest cumulative period of time throughout the Pleistocene, thereby explaining: (1) the lack of tors in such areas as the product of ‘average’ glacial conditions preferentially removing tors or dampening their production rates, (2) the survival of high relief tors during glaciation if they occupied summits too narrow to develop thick and erosive glacier ice, and (3) the survival of subdued tors in areas glaciated less regularly during the Pleistocene.

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.

The sedimentology and stratigraphy of a multi-phase glaciation sequence dating to Marine Isotope Stage 6 in the Rakaia Valley, South Island, New Zealand, is presented. This outcrop presents an example of the depositional signature of an end member of temperate valley glaciation, where voluminous sediment supply in a tectonically active setting combines with high annual temperatures and low seasonality to generate significant year-round glacifluvial activity. Such glacial systems produce geological-climatic units that are dominated by thick sequences of aggradational gravels and proglacial lake sediments trapped behind outwash heads during deglaciation. At Bayfields Cliff, outwash sequences record an oscillating glacier margin marked by a sequence of glacier-fed, Gilbert-type deltas. The deltas are cut by numerous small-scale, syndepositional, normal faults indicating both loss of glacier support and melt-out of buried ice. A larger-scale thrust fault system reflects late-stage ice overrun. Braid plain gravels and chaotic disturbed glacial lake sediments are also recorded. A notable feature of these systems is the virtual absence of till in an environment with much other evidence for proximal ice. Cumulatively we regard these sediment-landform associations as diagnostic of debris-laden, perhumid, temperate valley glacier systems.

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.

Isolated NE-SW stretching the Helan Mountain massif, separating the temperate grassland of the Ordos plateau from the Tenggeli Desert, is a key position of studying the glacier development in west China as well as the coupling conditions of climate change with tectonic uplift. The glacial landforms and deposits including cirques, peaks, knife-edge ridges, lateral moraines, and terminal moraines distribute above 2800 m a.s.l. in the middle part of the Helan Mountain. This distribution indicates that here was once glaciated during the late Quaternary. Morphology features show a clear sequence of landscape forming events took place throughout the Helan Mountain. Laboratory optically stimulated luminescence (OSL) and accelerator mass spectrometry radiocarbon dating (AMS 14C) results indicate a late history of glacial advance. Late Pleistocene glaciers in the middle part of the Helan Mountain advanced to near their positions at least four times, and the glacial sequences can be assigned as the middle stage of last glacial cycle (MIS3b, 43.2±4.0 ka), last glacial maximum (LGM, ∼18 ka), late glacial (12.0±1.1 ka) and neo-glacial (3.4±0.3 ka) respectively. Adopting equilibrium line altitude ∼2980 m of last glacial maximum and the modern theoretical snowline altitude ∼4724 m as the maximum amplitudes, and the standard marine isotope curve (MIS) as the glacial equilibrium line change since the Gonghe Movement (150 ka), the relationship between the mountain altitude and glacier development is discussed herein. Compared with other environmental indexes such as the loess-paleosol and ice core, conclusions are made that glacier advances in the Helan Mountain during the late Quaternary obviously depended on the coupled control of tectonic uplift of mountain with the climate condition. It is at last glaciation that the mountain reached the altitude above snowline and coupled with the glacial climate. The glacial advances occurred in the early and middle stages of last glacial cycle after the Gonghe Movement.

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.