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Cave studies enable us to unravel valuable information on landscape evolution. In glacial settings, the glacial cycles induced fluctuations in the underground hydraulic regime, sediment availability and base level in adjacent caves. Here, we present our work on the Grønli-Seter cave system in Northern Norway, which comprises >8 km of passage length at an elevation between 250 m and present sea level. By linking cave morphology and deposits to shifting glacier configurations and external base level changes during the last deglaciation and the Early Holocene, we establish how the hydraulic conditions in the cave system shifted in pace with glacier fluctuations. Maze sections and phreatic loops appear in a hydraulic confined setting close to the interface between the calcite marble and the overlying mica schist. Scallops in the cave walls demonstrate slow, ascending water flow, evidence of subglacial speleogenesis under wet-based, topographically constrained glaciers with a gentle surface slope. Moreover, cave morphology and clastic deposits indicate various hydrological phases of descending water flow, stagnant conditions, and excessive flow rates. Our work establishes that the last glaciation and deglaciation had an insignificant effect on the cave system's solutional development. In contrast, the cave sediments reveal diverse hydraulic conditions that may be related to shifting glacier configurations. This research offers valuable insights into glacier ice-contact speleogenesis and landscape development in glacial terrains. [Display omitted] • Reveal the relationship between cave morphology, deposits and glacier fluctuations. • Relate ice-contact speleogenesis to the glacial valley development. • Identify shifting hydrological conditions in the caves during the last deglaciation. [ABSTRACT FROM AUTHOR]

Aeolian dunes in the Moravian Sahara developed during at least two distinct cold periods of the Last Glacial Period (LGP). Their two-phase development was previously deduced solely from the different orientations of dune crests without knowing the dunes' internal structure. Therefore, the aim of this study is to reveal the internal structure of the multi-generational dune system, developing a relationship between these dunes and bedrock. A combination of data was obtained from boreholes and ground-penetrating radar (GPR). GPR profiles were measured in places where the boreholes were drilled to obtain high-resolution combination data. Furthermore, models of aeolian sediment thickness and ground-water level were made using a spatial interpolation method (ordinary kriging with spherical semivariogram model) to interpret the GPR results and to investigate a relationship between the bedrock and dune patterns. Internal dune structures confirm the hypothesis of multi-generational development of this dune field. In addition, the aeolian sediment distribution was influenced by the bedrock topography. Finally, this study confirms that a change in LGP atmospheric circulation over Central Europe is the main controlling factor in forming the Moravian Sahara dune field. • Multiphase dune field development distinguished in GPR profiles and boreholes. • Laminae azimuths revealed the change in LGP atmospheric circulation. • Bedrock surface influenced the spatial distribution of aeolian sediments. • Aeolian sediment model shows accumulation and deflation zones in dune field. [ABSTRACT FROM AUTHOR]

River terraces are among the most intriguing geomorphic features that have been reported from the Peruvian Andes hosting some of the most classical staircase terrace systems. Here, we explore how the large-scale tectonic architecture of the Andes in combination with cyclic variations of climate has impacted the generation and routing of sediment and the formation of these terrace systems. We invoke a hydroclimatic and geomorphic control where the landscape steepness and precipitation rates need to exceed a threshold for the release of sediment stored on the hillslopes, so that aggradation begins downstream in the valley. Once the sediment reservoirs on the hillslopes are void of material, the trunk streams start to recycle the previously deposited material, thereby forming a terrace level. Several of such out-of-phase cyclicities between water and sediment discharge have occurred during the Quaternary, and they were synchronous with the glacial periods at the global scale. Most of these climate shifts in Peru are explained by orbitally controlled changes in the solar insolation of the southern American continent and the Altiplano, which impacted the strength of the Andean jet. On its way towards the south, the jet becomes diverted towards the SE and thus away from the Andes where it intercepts with the mountainous topography of the Bolivian Orocline on the eastern flank of the Andes. These are also the latitudes where we mapped the thickest terrace deposits and the highest frequency of terrace occurrence along the Peruvian coast. Accordingly, the large-scale tectonic architecture of the Andes in combination with orbitally controlled variations in insolation has not only influenced the cyclic change in the strength of the Andean jet, but it has also conditioned the region along the Peruvian margin where the out-of-phase cyclicities between water and sediment discharge was large enough for thick staircase terraces to form. • The western Peruvian valleys host at least three sequences of Quaternary terraces. • Terraces were formed due out-of-phase cyclicities between water and sediment flux. • Terraces in Peru record orbital shifts in the strength of the Andean jet. • Terraces in Peru were formed during the Ouki, Minchin and Tauca pluvial periods. • The tectonic architecture of the Andes controls the location of Quaternary terraces. [ABSTRACT FROM AUTHOR]

The aim of this work is to build a new chronology of the Late Pleistocene glacial fluctuations in the Cantal Mountains and on the Cézallier Plateau (western Massif Central, France). The study of glacial landform-sediment assemblages is supported by the production of new exposure ages (n = 48) from (i) forty-three erratic boulders (36Cl and 10Be) spread over twelve glacial landforms, (ii) two ages from polished bedrocks (10Be) and (iii) three ages from depth profiles (10Be and 26Al) in tills. The results indicate that the majority of glacial deposits are attributed to Marine Isotopic Stage 2 (29 to 11 ka). From this dataset, four glacial stadials are discriminated: the Early-Local Last Glacial Maximum at 29–24 ka, (ii) Late-Last Glacial Maximum at 24–20 ka, (iii) a glacial still stand at approximately 17 ka, during a general deglaciation phase between 20 and 16 ka and finally (iv) a cirque stadial localized only in the Cantal Mountains at <16 ka. This new chronology strengthens the chronostratigraphy of the western Massif Central and highlights the sensitivity of the area to atmospheric circulation changes. • Revisions of glacial landform-sediment assemblages define four distinct glacial events. • Glacial fluctuations are dated to the MIS 2 with surface exposure ages using 10Be, 26Al and 36Cl (n = 48). • Two major glacier advances occurred during the Last Glacial Maximum, at 29–24 and 24–20 ka. • The paleoglacier is limited to the Cantal cirques from ~16 ka. • Paleoglacier from the western Massif Central are sensitive to north Atlantic paleoclimatic changes. [ABSTRACT FROM AUTHOR]

Aeolian sediments are widely distributed in the Qaidam Basin (QB) on the northeastern Qinghai-Tibet Plateau (QTP) and are ideal carriers of information for studying the environmental evolution of the basin. However, due to factors such as dry denudation and glacier erosion, there is a lack of palaeo-aeolian sediment records in the late glacial period. This study applied quartz optically stimulated luminescence (OSL) dating to fluvial-aeolian sequences in the TLH profile, which were exposed by river downcutting in the Tora River. In addition, OSL ages were combined with grain size and chemical elements to explore the sedimentary and environmental changes in the late glacial period recorded by palaeo-aeolian sediments in the QB. The results show that aeolian sediment accumulated earlier than the last glacial period in the QB and that the QB experienced multiple alternations of drying and wetting during this period. From approximately 70.45 ka BP to 60.87 ka BP, thick aeolian sediment with noticeable cross-bedding developed in this location, suggesting relatively dry environmental conditions and intense sand activities. From 60.87 ka BP to 58.56 ka BP, the environmental proxies revealed two distinct layers of fluvial deposits, with relatively coarse average grain sizes and weak chemical weathering, indicating wetter conditions. This region experienced alternations of drying and wetting between 58.56 ka BP and 41.09 ka BP, resulting in an aeolian sand layer and a freeze-thaw folded layer. This research is a good supporter of climate and environmental changes in the last glaciation. • The aeolian sedimentation in the Tora River Basin is controlled by climate factors. • Interaction between aeolian and fluvial facilitates formation and preservation of palaeo-aeolian sand. • Aeolian sedimentation exists in the last glacial period. [ABSTRACT FROM AUTHOR]

The Guadarrama and Somosierra mountain ranges form the eastern sector of the Iberian Central System and hosted numerous glaciers during the Late Pleistocene (MIS2). Glaciation was of low intensity with glaciers of small sizes, strongly controlled by the climatic context and the topography. This study analyses the shape, size, distribution and location of 96 cirques existing in these mountain ranges. In addition to the standard morphometric parameters and controlling factors (altitude, aspect and lithology) used in most studies, additional factors were considered here in relation to the pre-glacial relief and fracture network. The data were obtained and processed using ArcGIS 10.4 and relations between the parameters and controlling factors were evaluated using statistical methods. The results indicate that most are simple cirques, tending to isometry, with low vertical incision capacity, considerable variation in size and predominantly east-facing. In the context of the Iberian Peninsula and other European mountains, these cirques are among the most isometric, the lowest in height and present the least overdeepening. The development of these cirques has generally been the result of random combination of various factors. Thus: (i) the largest cirques are located at intermediate altitudes, with the headwall located on the main divides, at former torrential valley heads or at the headwalls of fracture corridor valleys, and are north-facing; (ii) the longest cirques are located at former torrential valley heads, on metamorphic bedrock (i.e. schists, slates) and on uniform slopes. Finally, the prevailing eastern aspects are explained by topoclimatic factors and are in agreement with previous studies, which have proposed a Circulation Weather Type (CWT) model throughout the Iberian Peninsula during the Last Glacial Period, similar to its current configuration. • Cirque morphometry from Guadarrama and Somosierra mountains was established. • This study including previous morphology and fractures as controlling factors. • Studied cirques are circular in shape, intermediate in size and shallow in depth. • The easterly prevailing aspect is related to a process of snow drift. • The prevailing aspect implies an Atlantic storm track pattern similar to present. [ABSTRACT FROM AUTHOR]

The tenet of the Milankovitch theory is that Northern Hemisphere solar insolation, controlled by Earth's orbital is responsible for cyclic climate variations. Eccentricity in this context is responsible for cyclic variability of 100 ka and may drive periodicity in climate change during the middle and late Pleistocene. Although abundant evidence exists for 100 ka cyclic climatic fluctuations driving glacial-interglacial cycles, our knowledge about the record of cyclic climatic changes preserved in terrestrial landscapes remains limited, especially over multi-millennial (several glacial-interglacial) timescales. The intermontane Yanqi Basin in the southeastern Tian Shan, Central Asia, preserves at least seven generations of alluvial surfaces spanning multiple glacial cycles and yields insights into the record of climatic fluctuations that lead to aggradation and incision of river systems. We complement existing chronologic data with two new cosmogenic 10Be depth profiles and four surface exposure ages of alluvial surface abandonment in the south Tian Shan piedmont within the Yanqi Basin. New surface-exposure dating reveals the successive abandonment of these surfaces with a 100 ka cyclicity between 5.1 ± 0.9 and ~550 ka and indicates that there were multiple aggradation-incision cycles. The superimposed 100 ka cycles of aggradation-incision are best explained by eccentricity-driven climate change. Within these cycles, sediment is produced during glaciations by glacial and periglacial erosion. However, due to the dry and cold conditions of the glacial periods in central Asia, there is little discharge available to transport and evacuate the sediment from the valleys to the piedmont. Later, during the glacial to interglacial transition, higher precipitation and high discharge due to glacial melt water resulted in higher transport capacity of the river beyond a threshold to evacuate sediment. Subsequent rapid incision occurs after the upstream sediment reservoir is depleted and its timing corresponds to the glacial to interglacial transition period in our study area. Compared with the aggradation and incision of the northern piedmont of the Tian Shan governed by the Westerlies, the sedimentary systems of the South Tian Shan piedmont within the Yanqi Basin are mainly controlled by eccentricity-driven glacial-interglacial cycles. • 10Be chronology of alluvial surfaces of south Tian Shan was reconstructed since 600 ka. • The abandonment of alluvial surfaces occurs over 100-ka cycles. • Aggradation-and-incision cycles are best explained by eccentricity-driven climate change. • Incision correlates with global glacial-interglacial transition periods. [ABSTRACT FROM AUTHOR]

Rock glaciers have traditionally been described as periglacial landforms and thus associated genetically with the presence of permafrost and a seasonal active layer. They have also been described as glacigenic in origin, in which the main rock glacier body contains glacier ice at depth. Other rock glaciers can be considered as relict where they contain no interstitial ice and are functionally inactive. Although all rock glaciers are to some extent polygenic, there is no clear, simple test that can be used to distinguish between different rock glacier types. This study proposes a simple and testable model for rock glacier classification based on their behaviour from evidence reported from the literature. The study then proposes an interpretive evolutionary model describing the temporal evolution of rock glacier surface movement through the year that can inform on its dynamical controls. This analysis provides an easily-deployed interpretive framework for the origins of rock glaciers. • This study proposes a simple and testable model for rock glacier classification. • Glacial, periglacial and paraglacial rock glaciers have different behaviours. • These different rock glacier types can coexist. • An individual rock glacier can transition between different types during its life cycle. [ABSTRACT FROM AUTHOR]

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

Abstract Here we reply to the discussion paper by Rasmussen (2018). In his discussion, Rasmussen (2018) raises concern on the use of the offshore sediment record as a way of constraining sediment flux out of Scandinavia over time, in order to inform landscape evolution models. We acknowledge that this approach is associated with large uncertainties, particularly in relation to source areas outside of Scandinavia that may have contributed to the sediment volume, and potential sinks that lie outside of our study area. Based on the comments by Rasmussen (2018), we present now a new complimentary set of inversions that explores an alternative for the imposed sediment volume originating from Scandinavia. Specifically, we assume that a significantly smaller Eocene sediment volume originates from Scandinavia, and a larger uncertainty on sediment volumes from all the considered time periods. We find that a lower Eocene sediment flux from Scandinavia makes Cenozoic plateau uplift more compatible with the offshore sediment record. However, these new plateau scenarios result in large-scale topography that is even less compatible with our reconstructed mid-Pliocene landscape, compared to the previous peneplain scenarios presented in Pedersen et al. (2018). We still find the scenario with substantial initial topography best compatible with our mid-Pliocene landscape, although this scenario cannot match the offshore record to the same degree when a lower Eocene sediment flux is assumed. On a final note, we emphasize that our inverse modeling approach is designed to incorporate geological information directly into the modeling, which will reduce the gap between geological observations and modeling. We therefore welcome any additional information that can inform and improve our modeling approach. However, we are dependent on some level of quantification in order to incorporate geological observations and exploit the full potential of this approach. Highlights • Here, we reply to the discussion paper by Rasmussen (2018). • We present new inversions exploring an alternative sediment flux from Scandinavia. • We find it likely that high topography existed here throughout the Cenozoic. • Widespread Cenozoic peneplain incision is inconsistent with the offshore record. [ABSTRACT FROM AUTHOR]

Abstract The valley of Lake Viedma represents one of the main ice flow axes during the Quaternary glaciations of Patagonia. Geomorphological mapping of the eastern sector of the lake, between the shoreline and the end moraine systems attributed to the Last Glaciation, allowed us to recognize a large number of ice-marginal and subglacial landforms. The landform assemblage of this area matches with previous models of surging glacier landsystems around the world. We identified the three geomorphological zones that characterise surging glacier landsystems, with some mixing of the zones, possibly related to multiple surges. The outer zone includes push moraines, thrust-block moraines, overridden moraines and hummocky moraines. In the middle zone, overridden moraines and hummocky moraines were developed. Finally, the inner zone is composed of megaflutes, crevasse-squeeze ridges, eskers and till eskers in a till plain. We interpreted these geomorphological features as evidence of surge activity of the Lake Viedma Lobe. A combination of topographic setting, soft-bedrock and the presence of a proglacial lake in contact with ice could have contributed to the development of surge activity in the Viedma paleoglacier. It could have been triggered by a change in the glacial thermal regime of the Viedma paleoglacier from polar during the Last Glacial Maximum to polythermal or temperate during the beginning of the Late Glacial. [ABSTRACT FROM AUTHOR]

Abstract Deglaciated mountainous areas are usually affected by a great range of paraglacial processes that involve progressively denudation of glacial imprints. This study focuses on paraglacial processes and glacial landform preservation in six zones located in two catchments of the Cantabrian Mountains (NW Spain). These zones are adjacent but display important topographic, lithologic and glaciation style differences. An analysis of how these variables conditioned the intensity and diversity of paraglacial processes in these zones was investigated through a detailed study of their relief, lithology and paleo glacier surface using GIS. A comprehensive cartography of paraglacial landforms was also accomplished, considering landslides, alluvial fans and rock glaciers that show signs of having been conditioned by glaciation. Moraines and debris-mantled slopes were also included in the analysis to examine their grade of preservation depending on the studied variables. Data comparison show that differences in glaciation style influenced paraglacial processes. In the ancient icefield area, relief modification by glacial action was limited and scarce paraglacial processes occur. By contrast, in the upper areas located in the southern ranges where an alpine-style of glaciation was installed, paraglacial processes were very active, generating many rock glaciers. Lithology explains some paraglacial landforms distribution: 1) Landslides are associated with incohesive (sandy and shale) rocks; 2) Rock glaciers mainly occur in quartzite areas; 3) In limestone areas subterranean drainage contributes to glacial landscape preservation, but suffosion dolines affect some glacial deposits. Topography is also a key factor in paraglacial processes: 1) Moraines are well-preserved in gently sloping valleys, but rare in the steeper where they are usually transformed into moraine (or debris)-mantled slopes; 2) Alluvial fans are more frequent in the steeper valleys, but more dissected by postglacial river action. 3) Elevation and orientation show little influence on paraglacial landforms, except in the generation of some periglacial features such as rock glaciers. [ABSTRACT FROM AUTHOR]

The mid- to high latitudes of Mars host assemblages of landforms consistent with a receding glacial landscape on Earth. These landforms are postulated to have formed >5 Ma under a different climate regime when Mars' orbital obliquity was on average 10° higher than today. Here, we investigate the spatiotemporal relationship between gullies and glacial landforms, both common in the mid-latitudes. Gullies are kilometre-scale landforms with a source alcove, transportation channel, and depositional apron. The glacial landforms comprise (1) extant viscous flow features (VFF) that extend from the base of crater walls into the interior of crater floors and are widely interpreted as debris-covered glaciers containing extant ice, and (2) landforms such as arcuate ridges at the base of crater walls that have been interpreted as relicts of more recent, less extensive glacial advances focussed on crater walls. We measure headwall retreat associated with glacial landforms and date their host-craters to constrain minimum headwall retreat rates. We record headwall retreat rates up to ~10 2  m My −1 for the youngest suite of glacial landforms, equivalent to erosion rates of wet-based glaciers on Earth and to headwall retreat rates associated with martian bedrock gully systems. We find extensive evidence for a single erosional episode dating 5–10 Ma, which postdates emplacement of the majority of VFF but seems to predate formation of the gullies. We propose that the wet-based glacial episode was associated with glaciation focussed on the crater walls rather than melting of the glacial ice deposits on the crater floors (VFF). This is consistent with our observations of crater wall morphologies, including the presence of arcuate ridges consistent with terrestrial glaciotectonic features that require liquid water to form, textural alteration of the eroded bedrock surface consistent with ice-segregation and frost-shattering, and the presence of downslope pasted-on terrain, tentatively interpreted here as glacial till deposits sourced from glacial erosion of the crater wall. The pasted-on terrain is usually interpreted as a thicker, latitude-dependant mantle located on sloping terrain formed from airfall of ice nucleated on dust, but we suggest that it has been reworked by glaciation and is predominantly glacial in origin. Although our results cannot substantiate that gullies are produced by meltwater, the discovery of this wet glacial event does provide evidence for widespread meltwater generation in Mars' recent history. [ABSTRACT FROM AUTHOR]

Cirques preserve important palaeo-climate information and have been investigated in various areas around the world. High Mountain Asia (HMA) contains the largest modern glacier inventory outside of polar regions, and tens of thousands of cirques. We analyzed 2831 largely ice-free cirques from five areas along a south-north transect in HMA, including central Himalayas (C. Himalayas), western Gangdise (W. Gangdise), eastern Tian Shan (E. Tian Shan), southern Altai (S. Altai), and northern Altai (N. Altai). These cirques are large relative to those in many parts of the world, and in the Himalayas, Tian Shan, and Altai their vertical dimensions are considerable. Their size variations show weakly allometric relations. The poleward decreasing trend in cirque floor altitudes is consistent with the reducing temperature trend toward high latitudes. Although just north of C. Himalayas, W. Gangdise is in their precipitation shadow and its cirque floors are higher. Relatively shallow cirques in W. Gangdise probably reflect low subglacial erosion associated with limited precipitation received from either the Indian monsoon or Westerlies due to this orographic effect. Lower cirque floor altitudes for north-facing cirques were likely caused by their lesser receipt of solar radiation. Because most mountains rose well above equilibrium-line altitudes of glaciers and were heavily glaciated, cirque aspects show symmetric vector strengths except in the lowest area, N. Altai. Eastward aspects in N. and S. Altai show the strong effects of Westerly winds in the past, as for present glaciers. Similarly, cirque aspects in C. Himalayas are more northeast-ward than modern glacier aspects, suggesting a stronger west wind influence in the past. North-facing cirques are lower and more frequent than south-facing, showing the general importance of solar radiation receipt, which is especially dominant in E. Tian Shan. [Display omitted] • HMA cirques are relatively large, with high elevation ranges except in W. Gangdise. • Nearly symmetric strengths of cirque aspects indicate extensive past glaciations. • North-facing cirques are lower and more frequent due to lesser solar radiation. • Eastward aspects suggest strong impacts of west winds in the Altai and C. Himalayas. • Poleward decreasing cirque floor altitudes are consistent with reducing temperature. [ABSTRACT FROM AUTHOR]

Knowledge of erosion rates through time is of great importance to understand the effects of tectonics and climate on the topographic evolution of mountain belts. In this study, we present a 10Be-based paleo-erosion record for the northern Qilian Shan (NE Tibet) during the last 4.2 Ma. This new record is based on samples from a magnetostratigraphically dated drillcore from the foreland of the northern Qilian Shan (i.e., the Hexi Corridor). The 10Be-based paleo-erosion rates obtained from the drillcore lie between ~40 and ~150 m/Ma, with the exception of two transient peaks at ~3.4 Ma (~330 m/Ma) and ~2.0 Ma (~220 m/Ma). These high values may result from transitions to a generally cooler climate with more pronounced changes between glacial and interglacial periods. Apart from these peak values, erosion rates during the period from 4.2 to 2.8 Ma are rather low (~40 to ~70 m/Ma; mean: 50 m/Ma), whereas erosion rates over the last ~1.5 Ma are higher, ranging from ~80 to ~150 m/Ma (mean: ~112 m/Ma). We attribute the slower erosion between 4.2 and 2.8 Ma to a warmer climate, with more rainfall than today, and a lower relief in the sediment-source region. These factors led to a stabilization of hillslopes and caused erosion rates to be low. Subsequently, progressive cooling, aridification, and enhanced glacial and periglacial processes reduced the vegetation cover and increased hillslope erosion. In addition, ongoing rock uplift and concomitant river incision in the Qilian Shan may have increased the local relief. These factors explain the higher erosion rates in the past ~1.5 Ma. Available evidence on tectonic boundary conditions, drainage evolution, sedimentary environment, and paleo-climate conditions suggest that the geomorphology of the northern Qilian Shan has not significantly changed over that period. • We derive a 10Be-based paleo-erosion record for the Qilian Shan over the past 4.2 Ma. • Gradual cooling and glacial processes have increased hillslope erosion after 2.8 Ma. • Low erosion rates in the Pliocene were due to a warmer climate and a lower relief. [ABSTRACT FROM AUTHOR]

Knowledge of the sedimentary provenance and age of loess deposits can help reconstruct windblown dust activity in the source regions. However, we lack firm evidence to unravel the loess provenance on the offshore islands of China. In this study, we used geochemistry, micropaleontology, and optically stimulated luminescence dating to constrain the sedimentary provenance and age of the Shengshan Island loess on the continental shelf of the East China Sea (ECS). The sedimentary age of the Shengshan Island loess ranges from 75.9 ± 7.5 ka to 39.6 ± 3.4 ka, corresponding to low sea-level stands during the Last Glaciation. The zircon U Pb age spectrum of the Shengshan Island loess reveals a 96 Ma age peak, attributed to a source from the nearby granites, while the remaining age components are contributed by the Yangtze River sediments. The element characteristics of size-fractioned samples indicate that the Shengshan Island loess originates from the Yangtze River sediments, the surrounding granites, and dust from the Asian interior. The presence of the spores of the freshwater alga Concentricystes supports the conclusion that the Yangtze River sediments are the major source of the Shengshan Island loess. Thus, the Shengshan Island loess is dominantly derived from proximal dust activity with a minor proportion of the fine fraction derived long-distance dust transport. The local dust emissions from the Yangtze River sediments are directly driven by low sea levels and an arid environment on the continental shelf of the ECS during the Last Glaciation. However, this dust activity was terminated during the transition from the Last Glacial to the Holocene when the sea level rose. [ABSTRACT FROM AUTHOR]

Relict periglacial sorted nets are valuable indicators of past permafrost and climate states, but their field studies are usually challenging due to high time requirements and poor visibility. This study therefore tests the suitability of high-resolution digital elevation model and aerial photographs with a horizontal resolution of 0.5 m and 0.2 m, respectively, to map and analyse the geometry of 2000 sorted nets from the Last Glacial Period at one site in the Krkonoše Mts., Czech Republic. Since the sorted nets occupy an area of ∼1.79 ha, the density of their network accounts for ∼1117 cells per hectare. The sorted nets have a mean diameter of 3.46 ± 0.83 m, a mean height of 0.28 ± 0.10 m, and a mean estimated sorting depth of 0.94 ± 0.22 m. The number of sides ranges between three and ten, but averages 5.99 ± 1.13, and 83.4 % of the sorted nets are pentagonal to heptagonal, and their sides mostly meet at three-way junctions at a mean angle of 119.9 ± 25.6°. However, isometric sorted nets are rather rare as a length-to-width ratio attains 1.47 ± 0.28. The estimated sorting depth indicates that permafrost superimposed by ∼1 m thick active layer occurred at the study site at the end of the Last Glacial Period. Generally, the remotely sensed parameters of the sorted nets are consistent with field data previously collected at the same study site and literature reports including those on past regional environmental conditions. This proves the utility of the high-resolution airborne data to map and analyse the geometry of large sets of sorted patterns, which would be difficult in conventional field surveys. Consequently, remote sensing could bring a wealth of new information on sorted patterned ground and its characteristics from past and present periglacial landscapes, and aid in past permafrost and climate modelling. The collected dataset of the parameters of the sorted nets could also have many other applications such as for choosing an effective sample size or the minimum network size to be included in statistical comparisons in future patterned-ground surveys, and for validating automated mapping and/or delineation tools and models of patterned-ground growth. • Last glacial sorted nets were examined using high-resolution (<0.5 m) airborne data. • Length, width, and diameter of sorted nets differ by <13 % from ground-truth data. • Height of sorted nets is ∼35 % lower compared to ground-truth data. • Sorted nets developed within ∼1 m thick active layer over permafrost. • At least ∼30–100 sorted nets need to be sampled for their parameter errors <5 %. [ABSTRACT FROM AUTHOR]

Alpine ice varies from pure ice glaciers to partially debris-covered glaciers to rock glaciers, as defined by the degree of debris cover. In many low- to mid-latitude mountain ranges, the few bare ice glaciers that do exist in the present climate are small and are found where snow is focused by avalanches and where direct exposure to radiation is minimized. Instead, valley heads are more likely to be populated by rock glaciers, which can number in the hundreds. These rock-cloaked glaciers represent some of the most identifiable components of the cryosphere today in low- to mid-latitude settings, and the over-steepened snouts pose an often overlooked hazard to travel in alpine terrain. Geomorphically, rock glaciers serve as conveyor belts atop which rock is pulled away from the base of cliffs. In this work, we show how rock glaciers can be treated as an end-member case that is captured in numerical models of glaciers that include ice dynamics, debris dynamics, and the feedbacks between them. Specifically, we focus on the transition from debris-covered glaciers, where the modern equilibrium line altitude (ELA) intersects the topography, to rock glaciers, where the modern ELA lies above the topography. On debris-covered glaciers (i.e., glaciers with a partial rock mantle), rock delivered to the glacier from its headwall, or from sidewall debris swept into the glacier at tributary junctions, travels englacially to emerge below the ELA. There it accumulates on the surface and damps the rate of melt of underlying ice. This allows the termini of debris-covered glaciers to extend beyond debris-free counterparts, thereby decreasing the ratio of accumulation area to total area of the glacier (AAR). In contrast, rock glaciers (i.e., glaciers with a full rock mantle) occur where and when the environmental ELA rises above the topography. They require avalanches and rockfall from steep headwalls. The occurrence of rock glaciers reflects this dependence on avalanche sources because they are most common on lee sides of ridges and peaks where wind-blown snow enhances the strength of the avalanche source. To maintain positive mass balance, the avalanche cone developed in the winter must be sufficiently thick not to melt entirely in the summer, thus providing an ice accumulation area for the rock glacier. In the absence of rockfall, this would support a short cirque glacier. The presence of debris, however, facilitates the development of rock glaciers with lengths of hundreds of meters, thicknesses of tens of meters, and speeds of meters per year that are well described by numerical models. Numerical models are used to explore the alpine glacier response to its climate history. In warming climates, a debris-covered glacier can transform into a much shorter rock glacier, leaving in its wake a thinning ice-cored moraine. Rock glaciers will persist in landscapes well beyond debris-free counterparts because they have much longer response times to climate change. The headwaters of alpine basins with steep headwalls will therefore oscillate between glacier and rock glacier occupation over glacial-interglacial cycles, maintaining a means by which rock from the headwall can be conveyed away. This enhances the asymmetry of alpine ridgelines, with downwind valleys biting deeply into the range crests, as originally noted by G.K. Gilbert. [ABSTRACT FROM AUTHOR]

Glacial landsystems in the high-Arctic have been reported to undergo geomorphological transformation during deglaciation. This research evaluates moraine evolution over a decadal timescale at Midtre Lovénbreen, Svalbard. This work is of interest because glacial landforms developed in Svalbard have been used as an analogue for landforms developed during Pleistocene mid-latitude glaciation. Ground penetrating radar was used to investigate the subsurface characteristics of moraines. To determine surface change, a LiDAR topographic data set (obtained 2003) and a UAV-derived (obtained 2014) digital surface model processed using structure-from-motion (SfM) are also compared. Evaluation of these data sets together enables subsurface character and landform response to climatic amelioration to be linked. Ground penetrating radar evidence shows that the moraine substrate at Midtre Lovénbreen includes ice-rich (radar velocities of 0.17 m ns −1 ) and debris-rich (radar velocities of 0.1–0.13 m ns −1 ) zones. The ice-rich zones are demonstrated to exhibit relatively high rates of surface change (mean thresholded rate of −4.39 m over the 11-year observation period). However, the debris-rich zones show a relatively low rate of surface change (mean thresholded rate of −0.98 m over the 11-year observation period), and the morphology of the debris-rich landforms appear stable over the observation period. A complex response of proglacial landforms to climatic warming is shown to occur within and between glacier forelands as indicated by spatially variable surface lowering rates. Landform response is controlled by the ice-debris balance of the moraine substrate, along with the topographic context (such as the influence of meltwater). Site-specific characteristics such as surface debris thickness and glaciofluvial drainage are, therefore, argued to be a highly important control on surface evolution in ice-cored terrain, resulting in a diverse response of high-Arctic glacial landsystems to climatic amelioration. These results highlight that care is needed when assessing the long-term preservation potential of contemporary landforms at high-Arctic glaciers. A better understanding of ice-cored terrain facilitates the development of appropriate age and climatic interpretations that can be obtained from palaeo ice-marginal landsystems. [ABSTRACT FROM AUTHOR]

The dramatic changes that occurred to the post-glacial landscape in the headwaters of the Waipaoa River basin are a consequence of perturbations about the equilibrium that exists between the rate of tectonic uplift and fluvial incision. At times when the amount of coarse sediment delivered to channels exceeds the capacity of streams to remove it, the channel bed rises at the rate of tectonic uplift. Once bedload overcapacity is replaced by undercapacity and the alluvial cover is depleted, streams reestablish contact with bedrock and recuperate the time lost to fluvial incision. The first major perturbation occurred during the final phase of the last glaciation (ca. 33–17.5 cal. ka), when aggradation was driven by a climate-forced variation in the relative supplies of sediment and water. We suggest that the subsequent transformation of channels in the headwaters of the Waipaoa River basin, from alluvial to bedrock, occurred as the atmospheric and oceanic circulation converged on their contemporary patterns ca. 12 cal. ka. A second major perturbation that continues to the present began ca. 1910–1912 CE, when a massive increase in sediment load was accompanied by a modest increase in water discharge after the native vegetation cover in the headwaters was replaced by pasture. The processes of terrace creation and incision are inherently unsteady, and in five interim cases incision was arrested by a transient increase in the thickness of the alluvial cover that was a response to climatic forcing. Events that disrupted the native vegetation cover in the headwaters also modulated patterns of sediment dispersal and accumulation in other parts of the fluvial system and caused rapid, storm-driven infilling of the Poverty Bay Flats. Tectonic subsidence dictates the course of the Waipaoa River across Poverty Bay Flats which, because the modern rate of floodplain construction by vertical accretion is rapid relative to the amount of destruction by lateral channel migration, has remained virtually unchanged for the past 100 years. During this time the channel assumed a narrower, deeper form that is in equilibrium with the contemporary supply of sediment and hydraulic regime. [ABSTRACT FROM AUTHOR]

Rockfall is a significant geomorphic process in many mountainous regions that also poses a notable natural hazard risk. Most previous studies of rockfall erosion have investigated the mechanics and rates of local rockwall retreat and talus deposition, with only a few investigations of rockfall and/or associated talus considering larger spatial scales (i.e., drainage basin, mountain range). The purpose of the current research is to investigate the areal extent of rockfall-talus and controlling factors of its distribution over regional spatial scales (of order 10 2 km 2 ) in Kananaskis, Canadian Rockies to inform our understanding of its significance in mountain development. To achieve this goal, a large talus inventory is collected and analyzed for 11 steep tributaries of the Kananaskis River, Canadian Rockies. Talus accumulations associated with rockfall provide evidence about the nature and rates of rockfall activity that supplies sediment to these deposits and are the focus of the present study. To quantify the controls of rockfall-talus activity in this region, we analyze the association of talus deposits with structural geology, glacial topography, and temperature-related weathering (i.e., frost cracking). A total of 324 talus polygons covering a surface area of 28.51 km 2 are delineated within the 11 study basins, with the number of talus polygons in each study basin ranging from 1 to 73. Analysis of the talus inventory shows that cirques and glacially sculpted valleys are locations of notable talus accumulation in Kananaskis, with other locations of significant talus deposition being associated with thrust faults. We also found that the upper elevations at which talus deposits are typically found are the general range of elevations experiencing a notable number of days in the frost cracking window when this window is defined as − 3 to − 15 °C; no such association is found for the frost cracking window of − 3 to − 8 °C. Estimates of average erosion rates for all study basins combined are between 0.15 mm y − 1 (lower estimate) to 3.1 mm y − 1 (upper estimate). Rockfall activity is expected to have been most active for the several millennia following deglaciation (during the paraglacial period) when hillslopes were oversteepened. [ABSTRACT FROM AUTHOR]

High-resolution digital topographic data permit morphological analyses of glacial processes in detail that was previously infeasible. High-level glaciofluvial erosional scars in central Pennsylvania, identified and delimited using LiDAR data, define the approximate ice depth during a pre-Wisconsin advance, > 770,000 BP, on a landscape unaffected by Wisconsin glaciation. Distinctive scars on the prows of anticlinal ridges at 175–350 m above the valley floor locate the levels of subice meltwater channels. A two-component planar GIS model of the ice surface is derived using these features and intersected with a digital model of contemporary topography to create a glacial limit map. The map is compared to published maps, demonstrating the limits of conventional sediment-based mapping. Additional distinctive meltwater features that were cut during deglaciation are modeled in a similar fashion. [ABSTRACT FROM AUTHOR]

Overdeepened valleys are unambiguous features of glacially sculpted landscapes. They result from erosion at the bed of the glacier and their size and shape is determined by ice dynamics and the characteristics of the underlying bedrock. Major overdeepened valleys representing vertical bedrock erosion of several hundreds of meters are characteristic features of many trunk valleys in the formerly glaciated parts of the Alpine mountain belt. The thick sedimentary fill usually hinders attempts to unravel bedrock geometry, formation history and fill characteristics. Based on reflection seismic data and core-logs from multiple deep drillings we construct a detailed bedrock model of the Lower Salzach Valley trough, one of the largest overdeepened valleys in the European Alps. The analysed overdeepened structure characterized by a strongly undulating topography. Two reaches of enhanced erosion can be identified and are suggested to be related to variations in bedrock erodibility and a triple glacier confluence. The sedimentary fill shows clear characteristics of rapid infilling and subaqueous fan delta deposits indicate a strong influence of tributary streams. Associated surface lowering of the valley floor had a major impact on tributary stream incision but also on the available ice accumulation area at subsequent glaciations. The extent to which fills of earlier glaciations have been preserved from erosion during the last glacial maximum remains ambiguous and demands further exploration. To our knowledge the presented bedrock model is one of the best defined of any major overdeepened trunk valley. [ABSTRACT FROM AUTHOR]

Climatic or geologic controls, such as tectonics or glacial drainage, might impose constraints on landscape self-organization resulting in spatial patterns of rivers and valleys which do not obey the typical self-similar relationships found in most landscapes. The goal of this study is to quantify how such geologic constraints express themselves on channel network topology, spatial heterogeneity of drainage patterns, and emergence of preferred scales of landscape dissection. We use as an example a basin located in the Upper Midwestern United States where successive glaciations over the past thousand years have led to a pronounced spatially anisotropic channel network structure which defeats most scaling laws of fluvial landscapes. This is contrasted with another river basin in the North-Central U.S. which has been organized under the absence of major geologic influences and follows a typical self-similar channel network organization. We show how the geologic constraints have imposed a competition for space which is captured in the slope–local drainage density probabilistic structure, in the failure of self-similarity in basin-wide river network topology, and in the length-area scaling relationship being not typical of fluvial landscapes. Via a two-dimensional wavelet analysis and synthesis, we demonstrate the occurrence of a gap in the power spectrum which corresponds to the presence of preferred scales of organization, and characterize them through multi-scale detrending. The developed methodologies can be useful in advancing our geomorphologic understanding of how external controls might manifest themselves in creating a landscape dissection that is outside the norm and how this dissection can be studied objectively for understanding cause and effect. [ABSTRACT FROM AUTHOR]

The geomorphic complexity of the Kitimat fiord system, on the active margin of British Columbia, Canada, is analysed from several perspectives. Sub-glacial landforms and sediments show that grounded ice exiting the fiord system at the last glacial maximum streamed down Moresby Trough towards the Queen Charlotte trough mouth fan. After brief halts on the inner shelf, grounded ice margins cleared the fiord threshold perhaps by c. 15.5 ka cal. yrs BP, and certainly before 13 ka cal. yrs BP. Just outside the fiords, meltwater plumes deposited stratified glaciomarine sediments interbedded with submarine slides. Inside the fiords, thick glaciomarine sediments were deposited, and large transverse moraines formed during temporary halts in retreat. Several glacial outburst floods eroded the Kitkiata moraine and deposited distinctive mud deposits. Postglacial sedimentation on fiord floors has been spatially variable: drifts of mud > 90 m-thick corresponding with areas of low current velocity alternate with areas of non-deposition and erosion corresponding with areas of high velocity. The fiord system hosts more than a hundred morphologically diverse fan deltas that can be classified in the Prior and Bornhold (1989, 1990) system. Submarine mass transport was most frequent immediately following ice retreat (15.5–11.5 ka cal. yrs BP). The largest event (~ 1.2 km 3 ) involved failure of glaciomarine sediment on a submarine moraine at Squally Channel, and consequent movement of material into the adjacent deep basin. This event occurred post-13 ka cal. yrs BP. In the postglacial phase, mass transport continued on a lesser scale up to the present day, most intensively in Kitimat Arm. From the perspective of glacial landforms, postglacial sedimentation and mass transport, this Pacific active margin fiord system has some parallels with fiord systems on Canada's east coast passive margin, and with Norwegian fiords, but the intensive development of Holocene fan deltas is strongly distinctive. [ABSTRACT FROM AUTHOR]

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

The morphological evolution of the Barents-Kara Shelf is a graphic example of how erosion and glaciation reshape the Earth's surface. Decades of petroleum exploration sparked longstanding debates on the shelf's obscured Cenozoic history. As a result, the Barents-Kara shelf has almost become a benchmark of erosion models and techniques. Several studies along the edges of the Barents shelf focus on the local relationship between sediments accumulated off-shelf and the amount of erosion in the adjacent areas. However, there are no studies of the entire Barents-Kara region. To address this issue and test the regional estimations of erosion, we first compiled an up-to-date map of erosional products accumulated off-shelf and separated them into Quaternary (glacial) and pre-glacial successions. Mass balance between erosion and sedimentation coupled with numerical analysis of morphology of the Barents-Kara realm demonstrates that the dominant part of Quaternary erosion is expressed within modern cross-shelf troughs and fjords. This analysis also shows that at the beginning of the Quaternary the shelf was submarine, with average water depths of ca. 40–90 m. Using recently acquired borehole data and published thermo-chronological and morphological studies, we developed a new map of Cenozoic erosion of the Barents-Kara shelf. The predicted erosion of our new model is smaller than previously published. However, even reduced, our estimate of erosion volume is almost 50 % larger than the amount of off-shelf sediment. Generally, sub-sea erosion estimates are based on seismic methods and well logs reflecting compaction of sedimentary rocks caused by (now partly removed) load from above. This missing load, however, may comprise not only erosion, but also glaciation, as the shelf was repeatedly covered by thick ice caps. A reduction of erosional estimates by accounting for ice load may provide a balance between accumulated sediments and erosion estimates. [Display omitted] • Off-shelf sediment and erosion estimates do not balance for the Barents-Kara shelf. • Reconstruction of pre-glacial shelf requires 20 % more glacial off-shelf sediments. • Total Cenozoic erosion volume is 50 % larger than the volume of off-shelf sediments. • Traditional techniques of erosion estimates may fail in the Barents-Kara shelf. • Ice load on the strata could explain misinterpretation of compaction trends. [ABSTRACT FROM AUTHOR]

Laminated slackwater deposits have been identified in many karst caves related to fluvial and lacustrine sedimentation. However, sedimentological evidence rarely supports a glacial origin for these deposits, which was proposed by previous studies. The Torca La Texa shaft is located in a glaciokarst area that comprises numerous slackwater-type deposits, piled up in fining-upward sequences. A basal sandy erosive layer and millimeter-sized laminated rhythmite with interbedded flowstone characterize these sequences. Fining-upward layers of carbonate silt, clay, and minor quartz sand deposited in flooded conduits define the rhythmite lamination. The presence of allochthonous minerals indicates that the rhythmite sediment comes from the glacial erosion of nearby carbonate mountains. Two 234 U/ 230 Th radiometric ages dated the rhythmite deposits around 109 and 95 ka, coinciding with relative cold periods included in the MIS 5d-c. These cold periods were marked by a high annual seasonality, immediately after the glacial local maximum extension, in agreement with a varve-type deposit. The combination of these sedimentological mineralogical, geomorphological and paleoclimate information indicates that the rhythmite should be introduced into the studied cave during the summer melting of the glaciers, which produced the recharge of the karst aquifer, triggering cave floods. In addition, punctual glacier collapses would also have their imprint in the slackwater sequences with thicker, coarser and erosive sand deposits and the spring blocking by glaciers may have promoted floods inside the cave. Therefore, the studied rhythmite can be interpreted as glacial varves decanted during the relatively cold climate conditions. [ABSTRACT FROM AUTHOR]

The temporal pattern of postglacial rock-slope failure in a glaciated upland area of Ireland (the western margin of the Antrim Lava Group) was evaluated using both 36 Cl exposure dating of surface boulders on run-out debris and 14 C dating of basal organic soils from depressions on the debris. The majority of the 36 Cl ages (~ 21–15 ka) indicate that major failures occurred during or immediately following local deglaciation (~ 18–17 ka). Other ages (~ 14–9 ka) suggest some later, smaller-scale failures during the Lateglacial and/or early Holocene. The 14 C ages (2.36–0.15 cal ka BP) indicate the very late onset of organic accumulation and do not provide close limiting age constraints. Rock-slope failure during or immediately following local deglaciation was probably in response to some combination of glacial debuttressing, slope steepening and paraglacial stress release. Later failures may have been triggered by seismic activity associated with glacio-isostatic crustal uplift and/or permafrost degradation consequent upon climate change. The 36 Cl ages support the findings of previous studies that show the deglacial - Lateglacial period in northwest Ireland and Scotland to have been one of enhanced rock-slope failure. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We investigated chemical weathering trends within the fine-grained (< 63 μm; silt and clay) fraction of sediments collected from meltwater streams emanating from glaciers in the McMurdo Dry Valleys (MDV; Wright and Taylor Valleys) by integrating grain size, BET surface area, and whole-rock geochemistry. While both valleys currently host cold-based glaciers, the sediment underlying the ephemeral glacial streams was deposited under differing glacial conditions. In Wright Valley (Clark Glacier stream), Brownworth and Trilogy drifts were deposited via cold-based glaciation, whereas the Ross Sea drift that underlies Delta Stream in Taylor Valley likely reflects contributions from wet-based ice. Wright Valley stream sediments are typically coarser grained and have a higher silt content as compared to Taylor Valley sediments. These sediments consist primarily of pyroxenes, quartz, and feldspars, with the percentages of pyroxenes and quartz systematically increasing downstream. The percentage of phyllosilicates ranges from 4 to 18% and decreases with downstream distance. In contrast, Taylor Valley sediments (Delta Stream) are finer-grained and exhibit lower percentages of both pyroxene and quartz and a significantly higher percentage of phyllosilicates (30–43%). Concentrations of all mineral phases remain relatively consistent in abundance with downstream transport in the Delta Stream transect as compared to Clark Glacier stream sediments. Standard chemical weathering indices, such as the Chemical Index of Alteration (CIA), indicate that chemical weathering is occurring within the silt and clay fractions of Antarctic stream sediments and is particularly pronounced in Delta Stream sediments that have BET surface area measurements > 40 m 2 /g. Utilization of MFW (mafic-felsic-weathered) and A-CN-K (Al 2 O 3 -CaO + Na 2 O-K 2 O) plots, however, are more effective in discerning the extent and nature of chemical weathering in these stream systems. Ca and Na depletion observed within the sediments exhibiting the highest surface area in Delta Stream suggest that chemical weathering may result in pitting and/or incongruent dissolution of pyroxenes and feldspars, as well as the development of amorphous and/or nanophase weathering products. In contrast, Clark Glacier stream sediments do not have similar leaching trends in the fine-grained sediment fraction and exhibit minimal weathering overall. This may suggest that fine-grained material is being trapped on top of the Clark Glacier surface and has not yet been transported into the weathering environment of the hyporheic zone due to timing of sampling. Alternatively, complete dissolution of very fine-grained sediment could be occurring in this stream transect, and is therefore not preserved in the fine sediment fraction. Overall, the magnitude of chemical weathering observed between the two stream systems is ultimately related to the nature of the underlying drift (cold and wet-based drift deposition), dispersal patterns of eolian fines, and variable stream discharge rates. Thus, incorporation of local fine-grained sediment derived from the underlying glacial drift deposits and distributed via the varying wind regimes within the hyper-arid climate into active stream channels may facilitate incongruent mineral dissolution and development of weathering products, and ultimately influence the composition and concentration of meltwater stream solutes. [ABSTRACT FROM AUTHOR]

The Jizerské hory Mountains in the Czech Republic have traditionally been considered to be a highland that lay beyond the limits of Quaternary glaciations. Recent work on cirque-like valley heads in the central part of the range has shown that niche glaciers could form during the Quaternary. Here we report geomorphological and sedimentary evidence for a small glacier in the Pytlácká jáma Hollow that represents one of the most-enclosed valley heads within the range. Shape and size characteristics of this landform indicate that the hollow is a glacial cirque at a degraded stage of development. Boulder accumulations at the downslope side of the hollow probably represent a relic of terminal moraines, and the grain size distribution of clasts together with micromorphology of quartz grains from the hollow indicate the glacial environment of a small glacier. This glacier represents the lowermost located such system in central Europe and provides evidence for the presence of niche or small cirque glaciers probably during pre-Weichselian glacial periods. The glaciation limit (1000 m asl) and paleo-ELA (900 m asl) proposed for the Jizerské hory Mountains implies that central European ranges lower than 1100 m asl were probably glaciated during the Quaternary. [ABSTRACT FROM AUTHOR]

The origin and evolution of the enclosed depressions (pans) of southern France during the period from the Late Glacial to the Holocene are discussed on the basis of new stratigraphical, geophysical and chronological ( 14 C) data from the Canohès depression (Roussillon, Southern of France) and its nearby environment. The Canohès depression is non-karstic, excavated from Pliocene arkosic sands that were shaped by eolian erosion during cold stages of the Middle and Upper Pleistocene. The timing and controlling factors of eolian carving of the depression are discussed on the basis of geomorphological data, surrounding alluvial terrace chronology, preserved ledge within the depression and alluvial infill of the depression. Formation of the depression was controlled, locally, by climate variability and its consequences on vegetation and water table position and, regionally, by the sea base level. The enclosed depression probably started to form during MIS 6, reaching its maximum depth during MIS 2. Climate variability in the region is recorded in the depression's infill. The basal deposits are of fluvial origin and record the increase of moisture and temperature during the Early Late-Glacial. The first lacustrine deposits are observed during the Bölling/GI-1e stage, while continental sedimentation and drying occurred during the Alleröd and Younger Dryas stages. During the Early and Middle Holocene, lacustrine conditions prevailed, except during short periods of drying. The specific evolution of the Canohès depression as regards other such formations is discussed in light of regional deglaciation and climate chronology. A regional synthesis of eolian erosion is proposed. [ABSTRACT FROM AUTHOR]

In the southernmost part of the Parana Basin, records of the late Paleozoic glaciation occur in a discontinuous form preserved in paleovalley systems excavated in the crystalline basement. This paper addresses one of these paleovalleys, the Mariana Pimentel, which extends over 60 km with NW-SE valley direction and a constant width of 2.5 km. With the objective of demonstrating that the paleovalley worked as a fjord during the glaciation period, its origin as well as sedimentary fill and morphology were analyzed. The paleovalley morphology was obtained through electrical resistivity (electrical sounding and lateral mapping) and mathematical modeling in four transverse sections. The morphology of the paleovalley documented by the U-shape, steady width, and high depth reaching up to 400 m are typical features of modern glacial valleys. The sedimentary facies that fill the base of the paleovalley, such as rhythmites and dropstones with thickness up to 70 m and diamictites with faceted pebbles (up to 5 m thick) are signs of its glacial origin. During the glaciation period, the paleovalley had a connection to the epicontinental sea located to the northwest, extended toward Namibia, and was excavated by glaciers from the highlands of this region. Thus, the evidence attests that the Mariana Pimentel paleovalley was a fjord during the late Paleozoic glaciation. The duration of the late Paleozoic glaciation (which is longer than the Quaternary glaciation), the apatite fission track that suggests erosion up to 4 km thick in the study area, and the lack of preserved hanging valleys in the Mariana Pimentel indicate that the paleovalley once featured a higher dimension. Furthermore, the existence of paleofjords excavated in the border of the basement corroborates the idea of small ice centers controlled by topography during the late Paleozoic glaciation. [ABSTRACT FROM AUTHOR]

The present paper provides new information on Pleistocene glacial activity in a mountainous area of the Iberian Central System. A sediment analysis associated with Pleistocene modelling was carried out using: (1) granulometric and morphometric procedures, (2) quartz grain microtexture techniques (SEM) to discriminate between glacial and no glacial origins of sediments, (3) clay X-ray diffraction study to determine intra-Pleistocene climate variability, and (4) optically stimulated luminescence (OSL) absolute dating. The results show that the sediments were formed in two different phases associated with glacial dynamics, one of them was 35–30 ky BP and another was 25–20 ky BP, separated by a short intermediate warm-wet period. Identification of glacial phenomena is new for the northern slopes of the Guadarrama Mountains (facing the north Meseta, Duero basin), although they are not unusual within the general context of the Iberian Central System. From the data provided, we deduce that glaciation in these mountains was much more intense and widespread than had previously been thought because, on the northern slopes, glaciers occupied large areas reaching the base of the mountains. The evidence favours new interpretations of Pleistocene morphology in the centre of the Iberian Peninsula and, by extension, on the southwestern edge of Europe; it also highlights the sensitivity of mountainous areas with regard to Quaternary climate changes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The article presents the results of morphometric analysis of approximately 300 eskers in Poland, to the south of the Last Glacial Maximum. The measurements included their length, fragmentation, maximum width, elongation, sinuosity, orientation and presence of tributary ridges and their order. The analysed area of Poland is dominated with eskers of 1–3 km in length with the maximum length slightly exceeding 10 km. They are characterised by the average maximum width of 250 m, clear elongation, slight predominance of straight over sinuous forms, and the presence of tributary ridges of maximally second order. The distribution and morphological characteristics of eskers in Poland, to the south of the LGM were mainly influenced by the origination of forms on a permeable substrate in N-channels and a combination of N-channels and R-channels, complex genesis of eskers and superimposition of open crevasse sediments over the subglacial facies, as well as formation of eskers during older glaciations (MIS6-12) and their subsequent transformations and erosion under variable climatic conditions. The morphological and sedimentological features of analysed eskers support the theory of predominance of the synchronous model of esker formation in this area. The presented studies refine the understanding of eskers of older glaciations than the forms that originated within the extent of the Last Glacial Maximum. The research provides new insights into the nature of esker formation and subglacial meltwater drainage in the area of soft bed. • The article presents the morphological analysis of 293 eskers in Poland. • This is the first regional analysis of eskers older than the Last Glacial Maximum. • Eskers in Poland originated in N-channels and their combination with R-channels. • Eskers formed in N-channels constitute an important component of soft bed areas. [ABSTRACT FROM AUTHOR]

Abstract Pedersen et al. (2018) use offshore sediment volumes to carry out inverse modelling of the Scandinavian landscape during the Cenozoic. Close inspection of the source area(s) for the sediment volume used in the study reveals that multiple source areas were responsible for the sediments fringing Scandinavia. In addition to a much more complex origin of the sediments than just Scandinavia, no consideration about the caliber of the sediments, transport media, maturation of the sediments and climate is included in the modelling by Pedersen et al. (2018). The study exposes a large gap between geological observations and modelling. [ABSTRACT FROM AUTHOR]

Yibin area is located in the southwestern margin of Sichuan Basin of upper Yangtze River basin, close to the southeastern boundary of the Qinghai-Tibetan Plateau. The paleoclimatic characteristics recorded by Quaternary river sediments in this area can display the impact of uplift of the Qinghai-Tibetan Plateau on paleoclimate change of Sichuan Basin. In this paper, the macro-characteristics, clay minerals and the diagnosis geochemical elements characteristics of the sediments of terraces and floodplain were used as climatic proxies to explore the evolutionary process of the Quaternary paleoclimatic change in the study area. Key findings can be shown as follows: 1) warm and humid paleoclimate occurred during the Middle Pleistocene and the early Late Pleistocene (730–90 ka), shown by the high values of Al 2 O 3 , Fe 2 O 3 , Rb/Sr, chemical index of alteration (CIA, 82–97), illite chemical index (ICI, >0.5), kaolinite and the low values of Na 2 O, K 2 O, MgO, K 2 O/Al 2 O 3 , (CaO + Na 2 O)/Al 2 O 3 , illite, smectite, chlorite from the brown or brownish-red sediments of the terraces T5 to T3. 2) The reversal values of these geochemical and clay mineral proxies (e.g., values of CIA between 50 and 64) derived from grey and greyish-yellow sediments in terrace T2 and floodplain denote the dry and cold paleoclimate, emerging in the middle-late Late Pleistocene (50 ka), corresponding to the Baiyu glacial period of the Qinghai-Tibetan Plateau. Comparing the paleoclimatic evolutionary characteristics in Yibin area with those of the Three Gorges area of northeastern margin of Sichuan Basin from previous researches, this paper considers that during the Gonghe tectonic movement (0.15 Ma), the uplift of the Qinghai-Tibetan Plateau and its southeastern boundary intensified the Plateau winter monsoon and caused the southwesterly withdrawal of the Indian monsoon from Sichuan Basin. Consequently, the warm and humid paleoclimate at the northeastern and southwestern margins of the Basin had successively become dry and cold in the early and middle-late periods of the Late Pleistocene. • Paleoclimate information can be well preserved in terrace sediments in Yibin area. • The paleoclimate in Yibin area had changed from warm and wet to cold and dry since 50 ka. • Quaternary paleoclimate changed to dry and cold from northeast to southwest in the Sichuan Basin. • Tibetan Plateau's Gonghe tectonic movement enhanced the Plateau monsoon and blocked the Indian summer monsoon. • Influence of Indian summer monsoon weakened in the Sichuan Basin along the SW direction after 110 ka. [ABSTRACT FROM AUTHOR]

Although it is generally assumed that understanding the trigger factor leading to the transition from a progressive rock failure toward sudden and rapid events is better to risk management, the ability to identify triggering factors responsible for prehistoric catastrophic rock avalanches is still debated. Here we describe two rock avalanches (Ganqiu and Shuiqiu) in the Cuihua Mountain area of the Qinling Range, China, providing new mapping of rock avalanche source areas and deposits and absolute age constraint from cosmogenic 10Be surface exposure dating. Results reveal that the Ganqiu rock avalanche is controlled by three sets of joints, causing the 380 m high ridge to collapse. Debris filled roughly the entire V-shaped valley and has a width ranging from 250 to 470 m, extending ~1260 m from the base of the cliff. The Shuiqiu rock avalanche was sourced near the summit of Cuihua Mountain from a cliff above 60° that is mainly controlled by inherited fault and joints. The rock mass fell ~250 m as a giant blocky stream across the width of the valley floor, with the deposit extending ~300 m from the base of the cliff. Both events caused the large-scale collapse of ridge crests and developed into high-mobility rock avalanches with long runout. Cosmogenic 10Be surface exposure dating from seven different parts of the deposits revealed nearly coincident ages for both rock avalanches, 10.0 ± 0.9 ka for the Ganqiu rock avalanche and 9.5 ± 1.2 ka for the Shuiqiu rock avalanche. Because this region was not affected by valley glaciation, rock avalanches triggering by paraglacial stress release can be excluded. Moreover, without clear evidence for specific climatic conditions in the Qinling area circa 9–10 ka, a climatic trigger for the Cuihua Mountain rock avalanches is equivocal. Instead, we find coincidence between the concurrent exposure ages and paleoseismic records from the nearby Qinling North Piedmont fault (QNF). This coincidence of ages, combined with the fact that the M w 8.0 1556 CE Huaxian earthquake triggered numerous large rock falls in the Huashan Mountains at the eastern end of the Qinling Range, suggest that a large-magnitude earthquake centered in the middle-east section of QNF at ca. 8–11 ka may have triggered the Ganqiu and Shuiqiu rock avalanches. • Two rock avalanches in the Qinling Range (China) were mapped and dated. • Seven nearly uniform 10Be exposure ages constrains the two rock avalanches to 9–10 ka. • Large-magnitude earthquake is a likely candidate for two rock avalanches triggering in the north Qinling Range. [ABSTRACT FROM AUTHOR]

A sedimentological and structural study is presented of a push-moraine formed in front of the Scandinavian Ice Sheet margin on the Głubczyce Plateau located at the forefield of East Sudetes Mountains. The glacial succession, which is composed of basal and flow tills, and sand/gravelly-sand deposited mainly from sheet flows at the surface of the glacier's marginal fan, developed in the culmination zone of an inter-valley hill, the base of which constitutes tectonic horst built of Carboniferous sandstones. In the central part of the hill, glacial deposits form a set of up-thrust slices, on the basis of which the succession is interpreted as thrust-block moraine. It was formed most likely during the maximum extent of the Saalian (Drenthe) glaciation. The substratum's topography and geology strongly determined the moraine development. Resistant Palaeozoic bedrock formed a rigid surface along which overlying unconsolidated sediments were pushed in front of the advancing ice sheet margin. The diamicton, lying above the bedrock and beneath the glaciofluvial sand, was of key importance for glaciotectonic shortening and development of the push moraine. It underwent ductile shearing, and a décollement surface developed within it, possibly because of thin permafrost, which caused high pore-water pressure within underlying unfrozen diamicton during the ice sheet advance. The ice-marginal deformation was induced by compression forces developed within the ice sheet margin moving against a reversed bedrock slope. A complete understanding of the process of this glaciomarginal form development and its paleoclimatic meaning requires a three-dimensional analysis of the ice sheet behaviour during the time over a much larger area also outside the Głubczyce Plateau. The varied topography of the ice sheet substratum induced time-transgressive changes of the ice distribution within the marginal part of the ice sheet. High friction in some elevated areas resulted in progressive concentration of ice flow in lower lying areas, such as valleys, where friction was much lower. This phenomenon essentially influenced the ice sheet margin dynamics and thus could determine the distribution and scale of glaciotectonic deformations. • A glaciomarginal zone at the Głubczyce Plateau (foreland of the Sudetes Mountains, Saalian) was investigated. • The ice-marginal processes were strongly influenced by local topography and geology. • The thrust-block moraine was developed in the culmination zone of the ice-marginal obstacle. • The stress field was generated by compression forces within the ice sheet margin advancing against a reversed bedrock slope. • The ice sheet marginal dynamics were strongly controlled by subglacial topography. [ABSTRACT FROM AUTHOR]

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

Here we present dense acoustic and swath bathymetry data sets as well as geological age constraints that allow a new view on past glacial processes at the Siberian termination of Lomonosov Ridge in the Arctic Ocean between 81° and 84° 20′ N. Here, the seabed is marked by three sets of streamlined glacial lineations observed at present water depths of ~760 m to 1250 m. The shallower streamlined glacial lineations were likely formed during MIS 6 and the deeper ones during MIS 12. Other observations include recessional moraines and pockmarks on a flattened ridge crest. In the subsurface, an acoustically transparent unit above well stratified strata is interpreted as subglacial diamicton overlying pre-glacial sediments at an erosional contact. Furthermore, the diamicton is interpreted to have been deposited as lenses in glacially-eroded proximal settings. In contrast, some parts of the seafloor and subsurface show no glacial overprint in water depths as shallow as 819 m. To explain these findings, we propose that the Siberian termination of Lomonosov Ridge was covered by an ice mass of spatial and temporal variable thickness between ~780 to ~1250 m, that was likely composed of sea ice and thick icebergs calved from ice shelves. • Full swath bathymetry information from the Siberian part of Lomonosov Ridge • Submarine glacial landforms at present water depths of ~760 m to 1250 m • Glacially unaffected areas shallower than 1000 m present water depth • Hints for an composite ice mass with variable thickness between ~780 to ~1250 m [ABSTRACT FROM AUTHOR]

Gomance is a piedmont karst polje in the northern Dinaric Alps presenting geomorphological and sedimentological evidence of past glaciation. During the Pleistocene the polje was situated at the edge of the Snežnik and Gorski Kotar ice fields from where two outlet glaciers reached Gomance. The morphogenesis of the polje was reconstructed by means of geomorphological mapping, sedimentological studies, and ground penetrating radar (GPR) measurements, supported by hand-drillings. With GPR an almost entirely buried moraine system was also imaged and mapped, crucial in reconstructing the polje history. The depression was karstified and well drained without any surface streams before the Last Glaciation. When the glacier front reached the depression, the entire floor became covered by glacial and outwash deposits. Surface runoff dominated over karst drainage in a large part of the polje, particularly where distal outwash deposits with low effective porosity functioned as an aquitard. These deposits diverted surface drainage toward the lowest edge of the polje, which functioned as a ponor front along the entire length. The outwash system of the Gomance polje was active during the Last Glaciation as suggested by radiocarbon-dated outwash deposits. [ABSTRACT FROM AUTHOR]

The Pięć Stawów 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 Bølling/Allerød (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. [ABSTRACT FROM AUTHOR]

Glacial cirques reflect former regions of glacier initiation, and are therefore used as indicators of past climate. One specific way in which palaeoclimatic information is obtained from cirques is by analysing their elevations, on the assumption that cirque floor altitudes are a proxy for climatically controlled equilibrium-line altitudes (ELAs) during former periods of small scale (cirque-type) glaciation. However, specific controls on cirque altitudes are rarely assessed, and the validity of using cirque floor altitudes as a source of palaeoclimatic information remains open to question. In order to address this, here we analyse the distribution of 3520 ice-free cirques on the Kamchatka Peninsula (eastern Russia), and assess various controls on their floor altitudes. In addition, we analyse controls on the mid-altitudes of 503 modern glaciers, currently identifiable on the peninsula, and make comparisons with the cirque altitude data. The main study findings are that cirque floor altitudes increase steeply inland from the Pacific, suggesting that moisture availability (i.e., proximity to the coastline) played a key role in regulating the altitudes at which former (cirque-forming) glaciers were able to initiate. Other factors, such as latitude, aspect, topography, geology, and neo-tectonics seem to have played a limited (but not insignificant) role in regulating cirque floor altitudes, though south-facing cirques are typically higher than their north-facing equivalents, potentially reflecting the impact of prevailing wind directions (from the SSE) and/or variations in solar radiation on the altitudes at which former glaciers were able to initiate. Trends in glacier and cirque altitudes across the peninsula are typically comparable (i.e., values typically rise from both the north and south, inland from the Pacific coastline, and where glaciers/cirques are south-facing), yet the relationship with latitude is stronger for modern glaciers, and the relationship with distance to the coastline (and to a lesser degree with aspect) is notably weaker. These differences suggest that former glacier initiation (leading to cirque formation) was largely regulated by moisture availability (during winter months) and the control this exerted on accumulation; whilst the survival of modern glaciers is also strongly regulated by the variety of climatic and non-climatic factors that control ablation. As a result, relationships between modern glacier mid-altitudes and peninsula-wide climatic trends are more difficult to identify than when cirque floor altitudes are considered (i.e., cirque-forming glaciers were likely in climatic equilibrium, whereas modern glaciers may not be). [ABSTRACT FROM AUTHOR]

Solution pipes are abundant in Late Pleistocene aeolian calcarenites at Cape Bridgewater in southwestern Victoria, and were studied using field work, morphometric analysis, thin sections, mineralogical and chemical analyses, and OSL dating. The solution pipes are vertical tubes formed in aeolian limestone with matrix porosity. They are typically 0.1–1 m wide and 1–5 m deep, with rounded terminations and cemented rims up to 10 cm thick. They are overlain by palaeosols and filled mostly with palaeosol material; rhizoliths are commonly present in the solution pipe fills and the surrounding calcarenite. The solution pipes have formed by focused dissolution of aeolianite, relatively quickly after the sand deposition, and concurrently filled with soil as they developed. They most likely formed beneath trees (as a result of focused infiltration due to stemflow) or due to fingered flow (unstable wetting front that breaks into fingers as it moves downwards). Solution pipe formation was strongly dependent on climate; periods of solution pipe formation followed the deposition of aeolianites at the end of interglacials MIS 7, 9 and 11, when the dunes were stabilised by vegetation and there was sufficient rainfall for substantial subsoil dissolution. The cemented rims formed in the following drier glacial climates. Solution pipes are most abundant in the youngest aeolianite, probably reflecting the wetter climate at the end of MIS 7 that allowed a dense forest to cover the dunes. From MIS 5 to MIS 2 no deposition of calcareous sand occurred on Cape Bridgewater, and combined with a very wet interglacial period MIS 5e, resulted in additional karstification, allowing the pipes in the MIS 7 aeolianite to extend deeper and drill down into the underlying member. A well-developed calcrete layer drapes over these solution pipes, and probably formed during the dry, windy climate of the Last Glacial Maximum. [ABSTRACT FROM AUTHOR]

In this paper, we report cosmogenic isotope evidence for dramatic changes in sediment supply during glacial–interglacial climatic cycles in the Late Quaternary. Previous work on fluvio-glacial processes in cold environments has qualitatively revealed that significant increases in debris production occurred in glacial periods, due typically to accelerated glacial and periglacial processes on high-relief slopes, resulting in river aggradation (accumulation) in the drainage. In interglacial periods, rivers behave in the opposite way, forming incised valleys. However, little has been studied on climatically controlled production-and-reworking processes with radiometric evidence. The evidence presented here is from the northeastern margin of the Tibetan Plateau, where lateral growth of the plateau is now ongoing. Reconstructions of fluvial response to Quaternary glacial fluctuations are crucial also to better understand the active tectonic process in the region using geomorphological information. The Sijiquan River drainage basin on the north of the East Kunlun Mountains was investigated. Detailed geomorphological mapping of fluvio-glacial landforms indicates two phases of aggradation, each of which was followed by valley incision. 10 Be and 26 Al concentrations in fluvial terrace deposits suggest that these two aggradational phases correspond most likely to the penultimate and last glacial periods, assuming a low rate of surface erosion on the terraces and zero inherited concentration. On the other hand, present-day river gravel has higher concentrations in amalgamated samples of 10 Be and 26 Al than the terrace deposits. Surface-exposure and burial analyses based on grain-by-grain measurements of both 10 Be and 26 Al indicate that the present-day river gravel consists mostly of reworked grains from terrace deposits and underlying fluvio-lacustrine rocks in the drainage basin. It is concluded that significant changes in clastic sediment supply occur in cold environments in response to glacial–interglacial cycles; clastic sediments are transported from mountain slopes much more directly in glacial periods than in interglacial periods. This violates the common assumption for surface exposure dating that the inherited cosmogenic isotope concentration is constant through time. [ABSTRACT FROM AUTHOR]

The Fraser Lowland is interpreted as a complex paraglacial landsystem in the sense that all its landform units, landform and sediment associations, and thus the whole landsystem have been modified by nonglacial processes conditioned by glaciation. The late Pleistocene and Holocene processes of modification include slope erosion, glacimarine, marine, glacifluvial, fluvial, glacilacustrine, lacustrine, organic, mass movement, and aeolian. This complex paraglacial landsystem has transitioned from proglacial through marine to its present dominantly fluvial character. Landforms representative of each sediment redistribution process are described and a conceptual model is developed with relative sea level and sediment source changes as the primary drivers. The sediment wave and sediment exhaustion models are compared and illustrated in the context of this paraglacial land system. Anthropogenic modification during the past century (the Anthropocene) has complicated the paraglacial story and is shown to impact the incidence of natural hazards, especially in the context of hydroclimate change. [ABSTRACT FROM AUTHOR]

Many of the conceptual models developed for river networks emphasize progressive downstream trends in morphology and processes. Such models can fall short in describing the longitudinal variability associated with low-order streams. A more thorough understanding of the influence of local variability of process and form in low-order stream channels is required to remotely and accurately predict channel geometry characteristics for management purposes, and in this context designating process domains is useful. We define process domains with respect to glacial versus fluvial valleys and lateral confinement of valley segments. We evaluated local variability of process domains in the Colorado Front Range by systematically following streams, categorizing them into stream morphologic type and process domain, and evaluating a number of channel geometry characteristics. We evaluated 111 stream reaches for significant differences in channel geometry among stream types and process domains, location and clustering of stream types on a slope–drainage area ( S – A ) plot and downstream hydraulic geometry relationships. Although individual channel geometry variables differed significantly between individual stream types in glacial and fluvial process domains, no single channel geometry variable consistently differentiated all stream types between process domains. Hypothetical S – A boundaries between bedrock- and alluvial-bed channels proposed in previous studies did not reliably divide bedrock and alluvial reaches for our study sites. Although downstream hydraulic geometry relationships are well-defined using all reaches in the study area, reaches in glacial valleys display much more variability in channel geometry characteristics than reaches in fluvial valleys, less pronounced downstream hydraulic geometry relationships, and greater scatter of reaches on an S – A plot. Local spatial variability associated with process domains at the reach scale (10 1 –10 3 m) overrides progressive downstream relationships in low-order mountain streams of the Colorado Front Range. [ABSTRACT FROM AUTHOR]