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This research was carried out in north-central Poland, which was occupied by the ice sheet of the Saalian (Marine Isotope Stage [MIS] 6) and Upper Stadial of the Weichselian (MIS 2) glaciation. The application of the anisotropy of magnetic susceptibility (AMS) method supported by a digital elevation model (DEM) analysis of the orientation of glacial landforms allowed for the reconstruction of ice-sheet extent and ice movement directions of these two Pleistocene glaciations. The research used an innovative method of collecting AMS till samples from the glacial plateau areas. Based on the research, it was found that during the general recession of the ice sheet of the Saalian glaciation, a previously undescribed glacial transgression occurred, characterized by a different direction of ice-sheet movement. On the basis of detailed geomorphological studies of the area of terminal moraines, previously described in fragments, the maximum extent of the ice sheet during the Weichselian glaciation was clarified. The recession of the ice sheet of the Weichselian glaciation from the area of north-central Poland took place in four regressive or transgressive–regressive stages with variable directions of ice-sheet movement. The results obtained indicate the great potential of the AMS method in paleoenvironmental studies of glaciated areas. [ABSTRACT FROM AUTHOR]

This paper presents five sites located in the marginal zone of the Wartanian stadial within the Odranian Glaciation (MIS6a) on the border of the Central Polish Uplands and Lowlands, representing different glacial forms and geological structures: terminal moraine hill, undulating moraine hill, sedimentary margin of the ice sheet, kame hill, and outwash plain. This differentiation is also reflected in the petrographic composition of the gravels and the interesting surface microstructures of the Scandinavian erratic boulders. This small study area, with its high geodiversity, which we have identified and investigated, has considerable potential for sustainable development. Geotourism is a tool for this development in a peripheral tourist region, providing both economic benefits for the local population and conservation services for the geoecosystem. [ABSTRACT FROM AUTHOR]

Buried mounds have been identified on seismic reflection profiles in the southern Roosevelt sub-basin of the eastern Ross Sea, Antarctica. Since they have never been sampled, the composition of these mounds can only be inferred from their acoustic character. Previous studies have hypothesised that they are buried glacial moraines deposited by ice grounding near the paleo-continental shelf edge, suggesting the beginning of the growth of the West Antarctic Ice Sheet (WAIS) as early as the late Oligocene. This hypothesis conflicts with earlier evidence of the WAIS advance over the central-eastern Ross Sea. An alternative explanation for the origin of the mounds, as mud volcanoes, is formulated here on the basis of seismic reflection profile reprocessing and comparison with other, better studied, mound provinces in the Ross Sea. Shallow drilling is required to verify, which hypothesis is correct, and this has implications for various WAIS scenarios, ice volumes, and thermal rheological modelling. [ABSTRACT FROM AUTHOR]

Comprehensive geological, geophysical, geomorphological, and hydrophysical studies were carried out on the R/V Akademik Boris Petrov in the eastern Barents Sea and western Kara Sea in fall 2022. The research included multibeam echo sounding and seismic profiling, hydrological sounding, and sampling of water and sediments in the areas of oil and gas field development and along the Northern Sea Route. The expedition studied in depth the structure of the seabed relief and upper sedimentary strata at the given research sites. The distribution areas of various glacial landforms and modern geohazards were refined during the expedition. [ABSTRACT FROM AUTHOR]

The Pechora Sea is optimally located for studying the coalescence of a glacial and periglacial continental shelf zone in the high Arctic. Here, we present data acquired during cruises of the RV Akademik Nikolaj Strakhov in 2018–2021, revealing the distribution of submarine glacial landforms in the central part of the Pechora shelf area. Based on moraines and the distribution of glacial lineations, the extent of the ice sheet during the Last Glacial Maximum (LGM) is proposed. The crests of the moraine ridges and the slopes of their sides express a variation in morphology, and the ridges combine into irregular complexes. The moraines are primarily composed of coarse cobble-sized material with an addition of coarse sand and other sedimentary fractions. The mapped glacial landforms clearly indicate that an ice sheet extended over the area, while the Pechora basin, at the same time, was comprised of lowland characterized by a cryogenic subaerial landscape. Based on the result from this study, the extent and ice-flow pattern of the Barents-Kara Ice Sheet during the LGM were determined. [ABSTRACT FROM AUTHOR]

Morphological phases of moraines from north-oriented valleys are known in the Bohemian Forest. Detailed data from south-oriented valleys are still missing. This paper presents morphological phases of moraines from two valleys. Glacial landforms were defined by an accurate digital elevation model (DEM) and verified by field mapping. The extent and internal structure of the selected glacial landforms were refined by geophysical profiling. We have described 8 morphological phases of moraines in the Großer Schwarzbach cirque locality (south orientation) and 4 morphological phases of moraines in the Kleiner Rachelbach cirque locality (north orientation). In the north-oriented valley, the number of morphological phases of moraines corresponds to other north-oriented sites in the Bohemian Forest. In the south-oriented valley, the number of morphological phases of moraines exceeds the number of morphological phases of moraines in the north-oriented sites in the Bohemian Forest. [ABSTRACT FROM AUTHOR]

The aerial stratotype of the Chibit Glaciation in a stratigraphic chart of Quaternary deposits of the Altai–Sayan Mountains, which corresponds to the Last Glacial Maximum (LGM) or the fourth step of the Upper Neopleistocene of the Russian Stratigraphic Chart, is characterized. The reference geological sections of diamictons of the Chibit Horizon are described and positioned. The geomorphological scheme with contours of the LGM Chibit and Maashei glaciers, which is composed of materials of remote sounding, field geomorphological observations, and geological data, is presented. The boundaries of the ice-dammed Baratal Lake are shown for a flooding level of 1700 m, which corresponds to the upper terraces in the northeastern margin of the Kurai Depression. The boulder gravels, which are deposited as a result of the outburst of Baratal Lake, are found in an old valley of the Chuya River. They compose a terrace body 5–7 m high cut into the Chibit moraine. The latter is embedded into the Saldzhar superflood sequence, thus, the Saldzhar and Baratal outbursts have different ages and scales. [ABSTRACT FROM AUTHOR]

Olympus Mons (basement dimension is 550 × 600 km, absolute height is 21.1 km, relative elevation is 21.9 km, volume is 2.4 × 109 km3) is the largest volcanic edifice on Mars as well as on Earth. The Mars images of the regular combinations of features of volcanic and glacial forms on Olympus Mons have been interpreted and analyzed. The cardinal external similarity of these forms to the forms of large terrestrial tuyas of young volcanic regions was revealed. This, probably, testifies to their similar origin. The Olympus Escarpment, 3–6 km in height, bounds Olympus Mons at low latitudes (center is at 18° N, 113° E), which indicates that, during the formation of Olympus Mons, vast glaciers existed not only in the polar regions of Mars but far away from them. The distribution of extensive glacial moraines allowed us to evaluate the area of glaciation, equal to 1.5–2 × 106 km2, as well as the ice sheet thickness (about 3–6 km), comparable to the recent height of the Olympus Escarpment. Some distinct fragments of the glacial relief point to several phases of glaciations; the directions of the moraine lobe propagation record a clearly manifested asymmetry in the glacier distribution. In the SW, W, NW, N, and NE sectors of the Olympus Mons piedmont, the edge of the glacier was at a distance of 700–750 km from a crater; in the other zones, the glacier edge was at a distance of 500–600 km. Glacial and water-glacial formations, enriched in volcanic debris, are removed from the center of the volcano by colossal lahar-type mud-and-stone flows to the maximum (1100 km, Acheron Fossae) distance. These flows were formed as a result of the dramatical destruction of the walls of the glacial basin in which the Olympus tuya-volcano grew. A terrestrial analogue of a similar process is the catastrophic Jökulhlaup feature in Iceland, which is attributed to ice-filled calderas with volcanoes growing within them. [ABSTRACT FROM AUTHOR]

The Gondwana Late Palaeozoic Ice Age is probably best represented by the Dwyka Group in South Africa. Striated and grooved surfaces or pavements are commonly considered to have formed subglacially, as are diamictites which have been interpreted as in-situ or reworked tillites. These interpretations were tested by investigation of outcrops in formerly well-studied areas, throughout South Africa. Detailed analyses have focused on striated surfaces/pavements and surface microtextures on quartz sand grains in diamictites. The sedimentological context of four pavements, interpreted to be glaciogenic, display features commonly associated with sediment gravity flows, rather than glaciation. A total of 4,271 quartz sand grains were subsampled from outcrops that are considered mainly to be tillites formed by continental glaciation. These grains, analysed by SEM, do not demonstrate the characteristic surface microtexture combinations of fracturing and irregular abrasion associated with Quaternary glacial deposits, but mainly a mix of surface microtextures associated with multicyclical grains. The Dwyka Group diamictites warrant reinterpretation as non-glacial sediment gravity flow deposits. [ABSTRACT FROM AUTHOR]

The lack of evidence for large‐scale glacial landscapes on Mars has led to the belief that ancient glaciations had to be frozen to the ground. Here we propose that the fingerprints of Martian wet‐based glaciation should be the remnants of the ice sheet drainage system instead of landforms generally associated with terrestrial ice sheets. We use the terrestrial glacial hydrology framework to interrogate how the Martian surface gravity affects glacial hydrology, ice sliding, and glacial erosion. Taking as reference the ancient southern circumpolar ice sheet that deposited the Dorsa Argentea formation, we compare the theoretical behavior of identical ice sheets on Mars and Earth and show that, whereas on Earth glacial drainage is predominantly inefficient, enhancing ice sliding and erosion, on Mars the lower gravity favors the formation of efficient subglacial drainage. The apparent lack of large‐scale glacial fingerprints on Mars, such as drumlins or lineations, is to be expected. Plain Language Summary: Water accumulates under ice masses, including glaciers and ice sheets, lubricating the base of the ice and accelerating ice motion. On Earth, this glacial motion has produced scoured landscapes in northern Europe and North America. Mars lacks such large‐scale glacial erosion even in areas with other signs of widespread glaciation. This paper uses the existing framework describing the physical interactions of water and ice, and how they affect ice motion, to show that a lack of landforms recording glacial erosion is expected even if glaciation were widespread on Mars. Key Points: Glacial hydrology feedback dynamics can explain the lack of glacial sliding on the Martian geological recordSubglacial water drainage develops faster, and is more resilient under lower Martian gravityThe fingerprints of Martian wet‐based glaciation are predicted to be channels and eskers [ABSTRACT FROM AUTHOR]

The Late Paleozoic ice age (LPIA) span from latest Devonian to Late Permian (Lopingian) and was one of the three major Phanerozoic glaciations. Large continental ice sheets covered wide parts of Gondwana at high latitudes of the southern hemisphere during the Pennsylvanian and Cisuralian/Early Permian. Many paleoclimate reconstructions have been based on direct evidence of glacial deposits or indirect evidence (far-field effects) of stable isotope proxies and facies analysis of carbonate successions. In this study, we present for the first time Late Mississippian to Middle Pennsylvanian lithostratigraphy, microfacies analysis and stable isotope analyses (δ13C and δ18O) of the stratigraphic units in the Hadim Nappe sections in the Taurides of southern Turkey. Based on detailed sedimentological studies, 12 microfacies and 9 sub-microfacies were defined for this stratigraphic interval. The main microfacies types indicate restricted to open marine, shoal and lagoon or peritidal zones. Evidence from the microfacies and sedimentology, as well as isotope data (δ13C) recovered from the stratigraphic units (Yassıpınar, Gölbelen and Bademli sections) indicate that upper Serpukhovian-Moscovian successions of the Hadim Nappe were indirectly affected by Gondwana glaciation and during the Glacial Period II–III and C3 and C4 of the Australian glacial periods. Late Paleozoic global paleoclimatic changes are recorded in the stable isotope (δ13C and δ18O) record of the studied succession in Tauride Platform in Hadim area and correlate with Russian and Chinese Platforms. [ABSTRACT FROM AUTHOR]

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]

Sites of ice-stream discharge to the continental slope build trough-mouth fans from glacigenic debris flows (GDFs), subglacial meltwater flows, and suspended sediment. Thus, past ice configurations may be interpreted from the sedimentological record. This study links the records in cores, high-resolution seismic profiles, and multibeam swath bathymetry of Hatton Slope and Fan to the changing glaciological history in Hudson Strait, one of the largest ice streams of the late Pleistocene Laurentide Ice Sheet. 14C-AMS dates, X-ray fluorescence geochemical profiles, and oxygen isotopes in sixteen cores document sediment supply during the last glacial cycle, and earlier history is interpreted from seismic data. The Frobisher Bay slope sector has a long record of GDF deposits from severe glacial periods between MIS 6 and 22, with little impact of meltwater discharge. Mass-transport events and aggrading gravel-floored valleys dominate the northern Hatton slope sector. The central slope sector shows the greatest shelf break progradation by till deposition, with kilometre-spaced gullies heading at 700–730 mbsl from the last major grounding of the ice-stream on the upper slope during Heinrich event 3 (H3). The gullies pass downslope into ∼5 km wide valleys, which have been sites of sediment bypass since widespread meltwater flow in MIS 6 and show little aggradation since MIS 16. Intervening >50 m high ridges show alternating levee accretion and erosion by shallow mass-transport events. Downslope on Hatton Fan, GDFs are common and fill wide erosional channels that lead to the sandy braid plain of the central Labrador Sea. The channels of the southern sector and Saglek Slope have channeled turbidity currents down the NAMOC, and stratified contourite deposits accumulated on the fan. Over the MIS 1–3 period widely represented by cores, ice was grounded in Hatton Basin and on the upper slope to 700 m water depth only immediately prior to H3. Older and younger H events had a floating ice-shelf in Hatton Basin, and sedimentation was dominated by the retreat of that ice shelf to Resolution Island. Distal cores show no systematic difference between the H1–top H3 interval and the base H3–H5 interval. Given the supply of carbonate detritus of consistent composition back to at least H5, any MIS 3 deglaciation of Hudson Bay would require improbably high growth rates of ice sheets in the centre of the continent. • First multibeam swath bathymetric and seismic profiling of the Hudson Strait Ice Stream. • Glacigenic debris flows, and mass-transport events were outlined during MIS 6 and 16. • Glacial ice was grounded in Hatton Basin and on the upper slope to 700 m over MIS 1-3. • Lack of a systematic difference between H1–H3 and H4–H5 events raises the question about the deglaciation hypothesis during MIS 3. [ABSTRACT FROM AUTHOR]

Reconstructing mountainous landscape evolution throughout the Quaternary is challenging because of the poor long-term preservation of geomorphic records in a context of rapid surface dynamics and topographic rejuvenation. The Quaternary geomorphic evolution of the western European Alps has been strongly controlled by climatic oscillations between glacial and interglacial periods. Significant erosion and sediment remobilization during these glacial/interglacial cycles have left very few sedimentary archives to quantify the surface dynamics and paleo-environmental conditions within the mountain belt over the last hundreds of thousands of years. Alpine valleys within the periglacial zone are potential candidates to target long-term geological archives, since they may contain alluvial deposits that have been preserved from subsequent glaciations. In the Drac valley (French western Alps), three generations of paleo-valleys are preserved, each of which was filled with alluvial and lacustrine sediments in response to glacial damming downstream. The valleys were incised during subsequent times of glacial retreat, leading to the formation of epigenetic valleys. Detailed 3D mapping of the paleo-valleys was carried out using photogrammetric models to constrain their geometry. Mapping was combined with luminescence dating of alluvial deposits to reconstruct the temporal evolution of the Drac valley. This chronological framework, together with additional data from the literature, allowed us to quantitatively constrain the complex alluvial dynamics along the Drac river during the last ca. 230 ka. Poly-phased alluvial deposition occurred in the most recent paleo-valley between ca. 90 and 20 ka (i.e., from late MIS 5 to MIS 2) in a context of global climate cooling and major Alpine glaciation. Sediment infilling of the intermediate paleo-valley is dated at around 130 ka; i.e., during the late-glacial phase of the penultimate glaciation, at the abrupt warming transition between MIS 6 and MIS 5. Finally, the oldest paleo-valley was filled around 230 ka (during a sub-stage of MIS 7) probably in a cooling and glacial context. The overall alluviation pattern and chronology of the study area highlight the asynchronous and partially contrasting glacial dynamics between the different glacier systems (i.e., Drac, Bonne and Romanche/Isère glaciers) within the Ecrins-Pelvoux massif of the French western Alps. • Record of Pleistocene epigenic paleo-valley evolution in the French western Alps. • Alluvial sediment aggradation recorded during early, pleni & late-glacial periods. • Diachronous response of local Alpine glaciers to Pleistocene climate forcing. • Long-term estimate of fluvial incision rate (0.6–0.8 mm/yr) over the last 250 ka. [ABSTRACT FROM AUTHOR]

In this study, a glacial lake-outburst flood was documented in the immediate foreland of the maximum phase of the Wartanian (Warthian, Late Saalian, MIS 6) Glaciation at Adamów in south central Poland. The structural and textural analyses of the sediments, as well as palaeohydraulic analysis, were carried out in the proximal part of the outwash plain where a fragment of the floodwater drainage system comprising buried erosional channels have been documented. Their fill reached a thickness of up to 11 m and was composed of poorly sorted, massive gravels with boulders, as well as horizontally, sub-horizontally, low-angle, and cross-stratified gravels. The coarse sediments were found to be inversely and normally graded. These sediments constituted the records of two subsequent flooding episodes. In the channel fill, the lenticular accumulations of gravel were identified and interpreted as buried large gravel dunes, while exhibiting a thickness of up to 2.5 m. Traces of sediment diapirism at the contact of channel fill and underlying sediments were also documented. Deformation was observed to originate from liquefaction caused by the rapid depositional loading of flood deposits. The example used in this study exhibited that the impact of glacial lake-outburst floods in shaping the marginal zones and foreland of ice sheets in the North European Plain was higher than that considered earlier. This example also showed a different case of glacial outburst flood in the foreland of the Middle Pleistocene ice sheets of Europe than that already known, which includes the discharge of sub- or englacial meltwater reservoirs emanated from a large proglacial ice-dammed lake. [ABSTRACT FROM AUTHOR]

The continental shelf of Northwest Australia hosts an extensive tropical carbonate ramp that forms an important template for the interpretation of similar systems in the sedimentary record. Yet, little is known about its development from the middle to late Quaternary, a period of high frequency glacioeustatic changes in sea‐level and climate. This research describes core and seismic‐reflection data from a mid‐ramp to outer ramp transect at the Northwest Shelf. Core material includes the upper 70 m of International Ocean Discovery Program Site U1461 (Expedition 356), which covers the last 500 kyr. During arid glacials, sedimentation is characterized by inorganically precipitated carbonates, including aragonite‐needle mud and ooids. Ooids developed under shallow marine conditions on small‐scale flat‐topped platforms. Seismic and sedimentological evidence indicates that these platforms developed locally on top of the present‐day mid‐ramp and were typically only active during a single glacial period. Aragonite‐needle mud precipitated (inorganically) in shallow‐water areas. Much of these fine sediments were subsequently exported into deeper water where they mixed with pelagic carbonates. Humid interglacials are generally characterized by reduced sedimentation across the Northwest Shelf of Australia, resulting in the amalgamation of glacial lowstand deposits. Yet, substantial amounts of skeletal carbonates were deposited at the studied location during the Holocene and Marine Isotope Stage 11. These sediment accumulations are interpreted as a local feature caused by a decline in current energy. The study presented highlights a ramp system where climate is as important as sea‐level in controlling carbonate deposition. [ABSTRACT FROM AUTHOR]

The deglaciation record of the Ontario Lowland and Mohawk Valley of North America is important for constraining the retreat history of the Laurentide Ice Sheet, end-Pleistocene paleoclimate, and ice-sheet processes. The Mohawk Valley was an important meltwater drainage route during the last deglaciation, with the area around modern Oneida Lake acting as a valve for meltwater discharge into the North Atlantic Ocean. The Mohawk Valley was occupied by the Oneida Lobe and Oneida Ice Stream during the last deglacial period. Multichannel seismic reflection data can be used to generate images of preglacial surfaces and internal structures of glacial bedforms and proglacial lake deposits, thus contributing to studies of deglaciation. This paper uses 217 km of offshore multichannel seismic reflection data to image the entire Quaternary section of the Oneida basin. A proglacial lake and paleo-calving margin is interpreted, which likely accelerated the Oneida Ice Stream, resulting in elongated bedforms observed west of the lake. The glacial bedforms identified in this study are buried by proglacial lake deposits, indicating the Oneida basin contains a record of glacial meltwater processes, including a 60-m-thick proglacial interval in eastern Oneida Lake. [ABSTRACT FROM AUTHOR]

Many distinct glacial episodes in the past ~1 million years in the Central Lowlands of North America left behind a patchwork of glaciated landscapes of different ages and formed through different glacial, paraglacial, and proglacial processes. Herein, we synthesize and reconcile diverse data sources across nine states in the Central Lowlands to create a generalized landform regions map, incorporating information from surficial geology, ageconstrained glacial boundaries, soil properties and parent material, and topography. The resulting map presents regions of till plains, moraines, outwash plains, and glacial lakes with ages ranging from 10.2 cal ka BP to greater than 500 cal ka BP. This new map improves on regional perspectives of the glaciated Central Lowlands by modifying and reconciling boundaries to agree with a variety of spatial data sources with finer detail. This refined map enables a more accurate spatial analysis of the landform regions by reducing noise from imprecise boundaries. [ABSTRACT FROM AUTHOR]

Reconstructing the growth and decay of palaeo-ice sheets is critical to understanding the relationships between global climate and sea-level change and to testing numerical ice sheet models. In this study, we integrate recently acquired high-resolution 2D seismic reflection and borehole datasets from two wind-farm sites offshore of the Netherlands to investigate the sedimentary, geomorphological, and glaciotectonic records left by the Saalian Drenthe substage glaciation, when Scandinavian land ice reached its southernmost extent in the southern North Sea (ca. 160 ka, Marine Isotope Stage 6). A complex assemblage of glaciogenic sediments and glaciotectonic structures is buried in the shallow subsurface. The northern wind-farm site revealed a set of NE–SW-oriented subglacial meltwater channels filled with till and glaciofluvial sediments and an E–W-trending composite ridge with local evidence of intense glaciotectonic deformation that denotes the maximum limit reached by the ice. Based on the identified glacial geomorphology, we refine the mapping of the maximum ice sheet extent offshore, revealing that the ice margin morphology is more complex than previously envisaged and displaying a lobate shape. Ice retreat left an unusual paraglacial landscape characterised by the progressive infilling of topographic depressions carved by ice-driven erosion and a diffuse drainage network of outwash channels. The net direction of outwash was to the west and southwest into a nearby glacial basin. We demonstrate the utility of offshore wind-farm data as records of process–form relationships preserved in buried landscapes, which can be utilised in refining palaeo-ice sheet margins and informing longer-term drivers of change in low-relief settings. [ABSTRACT FROM AUTHOR]

Fjords are glacially carved estuaries that profoundly influence ice-sheet stability by draining and ablating ice. Although abundant on modern high-latitude continental shelves, fjord-network morphologies have never been identified in Earth's pre-Cenozoic glacial epochs, hindering our ability to constrain ancient ice-sheet dynamics. We show that U-shaped valleys in northwestern Namibia cut during the late Paleozoic ice age (LPIA, ca. 300 Ma), Earth's penultimate icehouse, represent intact fjord-network morphologies. This preserved glacial morphology and its sedimentary fill permit a reconstruction of paleo-ice thicknesses, glacial dynamics, and resulting glacio-isostatic adjustment. Glaciation in this region was initially characterized by an acme phase, which saw an extensive ice sheet (1.7 km thick) covering the region, followed by a waning phase characterized by 100-m-thick, topographically constrained outlet glaciers that shrank, leading to glacial demise. Our findings demonstrate that both a large ice sheet and highland glaciers existed over northwestern Namibia at different times during the LPIA. The fjords likely played a pivotal role in glacier dynamics and climate regulation, serving as hotspots for organic carbon sequestration. Aside from the present-day arid climate, northwestern Namibia exhibits a geomorphology virtually unchanged since the LPIA, permitting unique insight into this icehouse. [ABSTRACT FROM AUTHOR]

The Laurentide Ice Sheet (LIS) was the largest ice sheet during the last glacial period. An accurate representation of its behavior during the last deglaciation is critical to understanding its influence on and response to a changing climate. We use 10Be dating and Bayesian modeling to track the recession of the southwest sector of the Labrador Dome of the LIS along an ~500-km-long transect west of Lake Superior during the last deglaciation. This transect reflects terrestrial ice-margin retreat and crosses multiple moraine sets, with the southwestern part of the transect deglaciated by ca. 19 ka and the northeastern part deglaciated by ca. 10 ka. The predominant behavior of the ice margin during this interval is near-constant retreat with retreat rates varying between ~59 m/a and 38 m/a. The moraine sets mark standstills and/or readvances that in total constitute only ~17% of the retreat interval. The spatial and temporal pattern of ice-margin retreat tracked here differs from existing reconstructions that are based on using isochrons to define ice-margin positions. Acknowledging the uncertainties associated with the modeled ages of ice-margin retreat, we suggest that the overall retreat pattern is consistent with forcing by a gradual increase in Northern Hemisphere, high-latitude summer insolation. The pattern of ice-margin retreat is inconsistent with Greenland ice-core temperature records, and thus these records may not be suitable to drive models of the LIS. [ABSTRACT FROM AUTHOR]

Northern British Columbia was repeatedly covered by the Cordilleran Ice Sheet (CIS) during the glacial periods. However, its mountainous terrain and remote location have thus far impeded our understanding of the central sector of the ice sheet. The improved resolution of remotely sensed data provides new opportunities to unravel the glacial history of this inaccessible location. Here, we present a comprehensive map of glacial landforms for the central sector of the CIS (55° to 60° N). Seven landform categories were mapped: ice flow parallel lineations, moraines (CIS outlet glacier moraines, Late Glacial moraines and moraines of unknown origin), meltwater channels (lateral and submarginal, subglacial, proglacial, and meltwater channels of unknown origin), kame terraces, eskers (single ridges and esker complexes), perched deltas and subglacial ribs. Collectively, these landforms provide a record of the extent, thickness and behaviour of the CIS, the direction of its movement and pattern of ice retreat. [ABSTRACT FROM AUTHOR]

Since the discovery of glacial features on sub-Antarctic Marion Island, the character and extent of a historic glacial period have remained an important research focus for earth science investigations. Previous glacial reconstructions were limited to mostly pre-GPS field observations and pre-digital mapping through a Geographic Information System. With the aid of GPS field mapping, high-resolution satellite imagery and a digital surface model with a 1 × 1 m cell resolution, this paper provides a comprehensive, geo-rectified spatial geodatabase and map of Marion Island's glacial geomorphology. The geodatabase includes an inventory of glacial erosional (e.g. striations) and depositional (e.g. moraines) features compiled from existing records as well as new features mapped from recent field observations. The final map and the geodatabase, which is downloadable as ESRI layerpackage files, will aid future field investigations and modelling applications to understand Marion Island's Quaternary landscape evolution and post-glacial ecological succession. [ABSTRACT FROM AUTHOR]

This study presents a 1:25,000 geomorphological map of the northern sector of Ulu Peninsula, James Ross Island, Antarctic Peninsula. The map covers an area of c. 250 km², and documents the landforms and surficial sediments of one of the largest ice-free areas in Antarctica, based on remote sensing and field-based mapping. The large-scale landscape features are determined by the underlying Cretaceous sedimentary and Neogene volcanic geology, which has been sculpted by overlying ice masses during glacial periods. Paraglacial and periglacial features are superimposed upon remnant glacial features, reflecting the post-glacial evolution of the landscape. The study area can be broadly separated into three geomorphological sectors, according to the dominant contemporary Earth-surface processes; specifically, a glacierised southern sector, a paraglacial-dominated eastern sector, and a periglacial-dominated central/northern sector. This map provides a basis for further interdisciplinary research, and insight into the potential future landscape evolution of other parts of the Antarctic Peninsula as the climate warms. [ABSTRACT FROM AUTHOR]

Geomorphic mapping, landform and sediment analysis, and cosmogenic 10Be and 36Cl ages from erratics, moraine boulders, and glacially polished bedrock help define the timing of the Wisconsinan glaciations in the Chugach Mountains of south-central Alaska. The maximum extent of glaciation in the Chugach Mountains during the last glacial period (marine isotope stages [MIS] 5d through 2) occurred at ~50 ka during MIS 3. In the Williwaw Lakes valley and Thompson Pass areas of the Chugach Mountains, moraines date to ~26.7 ± 2.4, 25.4 ± 2.4, 18.8 ± 1.6, 19.3 ± 1.7, and 17.3 ± 1.5 ka, representing times of glacial retreat. These data suggest that glaciers retreated later in the Chugach Mountain than in other regions of Alaska. Reconstructed equilibrium-line altitude depressions range from 400 to 430 m for late Wisconsinan glacial advances in the Chugach Mountains, representing a possible temperature depression of 2.1–2.3°C. These reconstructed temperature depressions suggest that climate was warmer in this part of Alaska than in many other regions throughout Alaska and elsewhere in the world during the global last glacial maximum. [ABSTRACT FROM AUTHOR]

The Scandinavian Ice Sheet reached the Sudetes and Carpathian Mountains during the Elsterian glaciation. A long ice‐sheet piedmont marginal zone affected by the rugged mountain foreland topography and associated slopes originated. This study focuses on the hilly Rychleby Mts. foreland (Eastern Sudetes, Czechia), which was a part of the piedmont marginal foreland zone of the ice sheet. The basal regime was reconstructed through an investigation of the sedimentology, structural features, and the nature of ice‐sheet erosion of preglacial landscapes evident at two sites located ~3–5 km inside the maximum ice‐sheet extent. These sites show a preglacial relief buried by sub‐ to supraglacial sediments. The sites were located under an ice cover of max. 200 m. Evidence of cold‐based conditions (including palaeotors with delicate structures on the bedrock, almost absent striations on clasts, originally frozen unlithified sedimentary rafts) exists at both sites. Permafrost composed of coarse‐grained sediments was subject to brittle deformation at the base of the ice sheet, whereas permafrost composed of fine‐grained sediments underwent ductile deformation. The margin of the Scandinavian Ice Sheet in the Rychleby Mts. foreland was cold‐based, therefore glacial erosion was not sufficient to significantly remodel the palaeotors into roches moutonnées. During ice‐sheet decay, the preglacial landscape was partially buried by melt‐out tills and meltwater sediments. [ABSTRACT FROM AUTHOR]

Southeastern Tibet is one of the most glaciated regions on the Tibetan Plateau both at present and during the Quaternary. Numerical dating of glacial deposits has allowed the establishment of a provisional chronology of Quaternary glacial fluctuations in this region, with the oldest glaciation (Guxiang Glaciation) occurring in marine oxygen isotope stage 6 (MIS-6). During our recent field investigations, a morphostratigraphically older lateral moraine than that of the Guxiang Glaciation has been first identified, which is ∼500–600 m above the Guxiang Glaciation moraine and discontinuously preserved on valley shoulders in the Bodui Zangbo River valley, eastern Nyainqêntanglha Range in southeastern Tibet. Considering the moraine is best preserved at Nitong Village, here we name the glacier advance which deposited the moraine as "Nitong Glaciation". Using electron spin resonance (ESR) technique, we dated the Nitong Glaciation moraine to 506.3±60.4 ka. Taking into account the age error and climatic conditions, we consider it most likely that the Nitong Glaciation occurred during MIS-12, although it might had happened sometime earlier. [ABSTRACT FROM AUTHOR]

In this study, the lichenometry studies of the Hoksar Glacier valley in Kashmir Himalaya, India supported by the extensive ground- and remote sensing-based glacial geomorphological mapping enabled the identification of the six episodes of glacier advances in the valley. Field-based geomorphologic evidence suggests that the glacial episode 1 (GEI) experienced the most extensive glaciation in the Hoksar valley extending ∼1 km down the valley (altitude 3565 m) from the current snout position of the Hoksar Glacier (altitude 3680m). Lichenometric dating of the moraines suggests that the GE1 episode is chronologically the oldest (∼480 ± 25 years) and GE6 episode the youngest (∼245 ± 10 years). The mean equilibrium line altitude (ELA) during the GE1 episode was calculated as 3755 ± 4 m compared to the observed present ELA position of 4060 ± 5 m, an upward shift of 305 m observed during the period. The spatio-temporal changes of the Hoksar Glacier during different episodes of the glacier advances until 2018 showed that the glacier area has shrunk from ∼212 ha during the GE1 to 100 ha at present losing an area of 112 ha (52%) during the period mainly as a result of the recent climate change. The recent observed glacier recession (1980–2018) is much higher (11 000 m2 a−1) compared to the past recession (1300 m2 a−1). The study provides valuable insights about the glacier recession in the Kashmir Himalayan region during the Late Holocene where knowledge about the past glacial history on a regional scale is generally poorly investigated. [ABSTRACT FROM AUTHOR]

Here we present the first compilation of sediment volumes, sedimentation rates, and chronology of Quaternary sediment packages along the entire marine margin of the Eurasian ice sheets (EurIS; British-Irish, Kara-Barents Sea-Svalbard, and Fennoscandian). This compilation allows for a subdivision of the EurIS development into three phases (2.6-1.5 Ma, 1.5-0.78 Ma, and 0.78-0 Ma). At the start of the Quaternary, sedimentation rates increased, relative to pre-Quaternary rates, by an order of magnitude. This abruptness in rate change excludes tectonic raising of landmasses as the main factor, but more likely reflects climate change through increased glacial erosion. The sediment distribution data suggest that the Kara-Barents Sea-Svalbard Ice Sheet (KBSIS) already was quite large at the beginning of the Quaternary, and well before 1.5 Ma it extended to the shelf edge and coalesced with the Fennoscandian Ice Sheet (FIS), which prior to 1.5 Ma most likely was located near the coast. Large ice streams and intense glacial erosion characterized the KBSIS in the 1.5-0.78 Ma time period, whereas the FIS at that time extended farther out on the continental shelf. After 0.78 Ma, a north-south change in EurIS development occurred. In the FIS and the British-Irish Ice Sheet (BIIS), large ice streams developed and shelf-edge glaciations occurred nearly 1 m.y. later compared to the KBSIS. The FIS and BIIS also repetitively coalesced in the North Sea. A significant drop in sediment input along the KBSIS marine margin, to the lowest Quaternary level, suggests a less erosive KBSIS. [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]

Pleistocene glacial activity was a major influence on runoff and sediment supply in many river systems across the Mediterranean. The geomorphological impacts of changes in sediment supply between glaciated headwater terrains and downstream depocentres spanning several glacial cycles are, however, poorly understood. By applying uranium-series and optically stimulated luminescence dating to fluvial and glacial sediments preserved on Mount Chelmos (2355 m a.s.l.) in southern Greece, we show how changes in the long-term coupling between glacial and fluvial systems are preserved within a major glaciofluvial outwash fan system that functioned during multiple cold stages. We also present evidence in the form of a cemented till unit, stratigraphically below younger Middle Pleistocene glacial deposits, yielding a U-series age close to the limit of the technique, indicating glaciation during Marine Isotope Stage (MIS) 16 - one of the most severe cold stages recorded in the Mediterranean. This is the first time such early glaciation has been directly recorded in Greece and the wider Balkans and is defined here as the Valvousian Stage based on glacial deposits on Mount Chelmos. Geomorphological and geochronological data point to the formation of a more extensive plateau ice field over Chelmos during MIS 12, another severe glacial period in the Balkans that corresponds with the Skamnellian Stage glaciation of Northern Greece. During this phase, very strong coupling of glacial and fluvial systems led to meltwater flood events transferring large volumes of sediment to lower valley zones culminating in the formation of an extensive glaciofluvial outwash fan complex and glaciofluvial terraces. A smaller plateau ice field during MIS 6 and localised valley glaciers between MIS 5d to 5c correlate with the Vlasian and early Tymphian Stage glaciations in Greece, respectively. The delivery of much less meltwater and sediment through a single valley during MIS 6 and MIS 5b to MIS 4 signalled the transition to progressively weaker glacial and fluvial system coupling. After MIS 4 the uncoupling of depositional zones from sediment sources in glaciated catchments led to fluvial incision of glaciofluvial outwash deposits in several valleys. Despite this incision, the glaciofluvial outwash fans preserve a record of glacial and fluvial system interactions during the Middle Pleistocene and early stages of the Late Pleistocene. • U-series ages provide the first chronology for moraines and glaciofluvial outwash in southern Greece. • U-series ages indicate that Mount Chelmos was glaciated multiple times during the Pleistocene. • Glaciation during MIS 12 marked a period of very strong glacial-fluvial system coupling. • Glacial–fluvial system coupling was controlled by the preferential transfer of sediment through specific valley systems. • Glaciofluvial outwash fans preserve a detailed record of glacial-fluvial system interactions. [ABSTRACT FROM AUTHOR]

Determining the grounded ice dynamics of deep-time glaciations is limited by the scarcity of well-preserved subglacial erosional features and their irregular distribution. In particular, small-scale erosional features known as s-forms that are subglacially sculpted in bedrock by water and/or ice are rarely preserved from the pre-Cenozoic record. A detailed re-examination of two late Paleozoic (late Carboniferous–early Permian) glacially-polished, surfaces at the base of the Dwyka Gp. within paleofjords located in the Kaokoveld region of northwest Namibia reveals a range of erosional features including: complex, multi-directional striae that crosscut each other, crescentic markings, chattermark trails, sinuous furrows, linear furrows, transverse troughs, comma forms, sichelwannen, muschelbrüche, cavettos, a pothole, and rock drumlins. The first study location in the Sanitatis paleovalley is previously undescribed and consists of striae and fractures on a polished granite bedrock surface located on the paleovalley floor. Striae, crescentic markings, and chattermark trails indicate ice movement to the west/northwest (striae mean azimuth of 276°). The second location in the Hoarusib paleovalley was previously described and is located on a multi-level, resistant, quartzite bedrock ridge close to or on the valley wall. This location contains numerous s-forms, striae, and fractures, as well as onlapping glaciogenic sediments, including diamictite plastered within a pothole. Some of these features are superimposed on rock drumlins. These erosional features were likely formed by a combination of pressurized subglacial meltwater and glacial abrasion underneath a glacier as it flowed over and around a resistant bedrock outcrop. Orientations of striae and chattermark trails at the second location indicate a primary direction of ice movement toward the west/northwest (striae modal azimuth of 275°), a minor secondary movement to the southwest (255°), and abundant third-order striae indicating ice flow around bedrock obstacles. However, cross-cutting relations suggest the primary and secondary striae orientations are not related to two distinct glacial advances as previously thought. The complex relationships between striae, fractures, and s-forms suggest that a combination of pressure melting, abundant subglacial meltwater, debris-rich basal ice, and variable ice flow paths around resistant obstacles was required to form these features. We conclude that the study locations were overridden by relatively thick (>210 m) warm-based or polythermal glaciers that were confined to a network of fjords as ice receded and stagnated. The glaciers flowed west into present-day Brazil during the late Paleozoic and likely overtopped the paleovalley walls during times of ice maxima. [ABSTRACT FROM AUTHOR]

In low relief Precambrian gneiss terrain in eastern Sweden, abraded bedrock surfaces were ripped apart by the Fennoscandian Ice Sheet. The resultant boulder spreads are covers of large, angular boulders, many with glacial transport distances of 1–100 m. Boulder spreads occur alongside partly disintegrated roches moutonnées and associated fracture caves, and are associated with disrupted bedrock, which shows extensive fracture dilation in the near surface. These features are distributed in ice-flow parallel belts up to 10 km wide and extend over distances of >500 km. Our hypothesis is that the assemblage results from (1) hydraulic jacking and bedrock disruption, (2) subglacial ripping and (3) displacement, transport and final deposition of boulders. Soft sediment fills indicate jacking and dilation of pre-existing bedrock fractures by groundwater overpressure below the ice sheet. Overpressure reduces frictional resistance along fractures. Where ice traction overcomes this resistance, the rock mass strength is exceeded, resulting in disintegration of rock surfaces and ripping apart into separate blocks. Further movement and deposition create boulder spreads and moraines. Short boulder transport distances and high angularity indicate that glacial ripping operated late in the last deglaciation. The depths of rock mobilized in boulder spreads are estimated as 1–4 m. This compares with 0.6–1.6 m depths of erosion during the last glaciation derived from cosmogenic nuclide inventories of samples from bedrock surfaces without evidence of disruption. Glacially disrupted and ripped bedrock is also made ready for removal by future ice sheets. Hence glacial ripping is a highly effective process of glacial erosion. [ABSTRACT FROM AUTHOR]

Slope failures are widespread phenomena in mid-latitude mountain environments that were glaciated during the Last Glacial Cycle. This is the case of the Aran valley, in the Upper Garonne catchment, Central Pyrenees, that included glaciers several hundred meters thick. Following postglacial warming and ice thinning, the recently deglaciated slopes were subject to intense stress readjustments - the so-called paraglacial dynamics. We have identified up to 135 major slope failures in the Aran valley, with only 10 units occurring outside the glaciated domain of the maximum ice extent of the Last Glacial. The presence of polished bedrock surfaces, till and moraine ridges next to some of these features evidence a close connection between glacial and slope processes. We have detected different types of slope failures affecting both bedrock (12 large catastrophic rock slope failures, 16 rock-slope deformation, 34 rockfalls, and 49 rockslides) and unconsolidated glacial sediments (14 slope readjustments on drift-mantled slopes). The average altitude of rock slope failures oscillates between 1551 and 1991 m, with a mean length ranging from 147 to 905 m and a width between 247 and 513 m. The affected surface is also highly variable, oscillating between 0.02 and 126.2 ha. Slope failures occur in different lithological settings, but they are most frequent in slate, lutite and limestone bedrocks. We conclude that most of the failures show a paraglacial origin, though other factors (i.e. lithology and topography) promoted slope instability. [ABSTRACT FROM AUTHOR]

The intricate interplay between subglacial topography and ice-sheet dynamics is key to the evolution of large ice sheets, but in Greenland as elsewhere the effects of longterm glacial history on landscape evolution remain poorly constrained. Here we measure abundances of cosmogenic 10Be and 26Al in bedrock and transported boulders to unveil the glaciation and erosion history of Dove Bugt, northeast Greenland. In agreement with studies of west Greenland, we find that apparent exposure ages increase with elevation from 9 ka to 13 ka in low-lying valleys to 21 ka to 204 ka on high-elevation, blockfieldcovered plateaus. We employ a Markov chain Monte Carlo inversion framework to constrain the probability of various erosion histories, and we quantify the residence time of samples within the upper 2 m of the bedrock subsurface-a measure defined as the cosmogenic nuclide memory. This cosmogenic nuclide memory exceeds 600 ka on the highest plateaus but is limited to less than 500 ka in most other high-elevation samples and to less than 100 ka at low-elevations. Our results define maximum limits for the fraction of ice cover during the past 1 Ma to ~70% on the Store Koldewey peaks and ~90% farther inland at Pusterdal, respectively. Minimum limits to ice cover, however, cannot be reliably constrained by the data. Finally, we propose that limited erosion on the highest plateaus of Store Koldewey since 0.6-1.0 Ma indicates a minimum age for fjord-plateau formation within this area of northeast Greenland. [ABSTRACT FROM AUTHOR]

Death Valley (California, USA) hosts iconic Cryogenian snowball Earth deposits, but the lack of direct geochronological constraints has permitted a variety of correlations and age models. Here, we report two precise zircon U-Pb isotope dilution-thermal ionization mass spectrometry dates for the Kingston Peak Formation: a volcanic eruptive age of 705.44 ± 0.28 Ma from the synglacial Limekiln Spring Member, and a maximum depositional age of 651.69 ± 0.64 Ma from the nonglacial Thorndike submember, which is below the Wildrose diamictite. These dates confirm that the Limekiln Spring and Surprise Members were deposited during the Sturtian glaciation, while the Wildrose submember is a Marinoan glacial deposit, and the overlying Sentinel Peak Member of the Noonday Formation is a Marinoan cap carbonate. Additionally, the age from the Thorndike submember supersedes existing radioisotopic ages from the Datangpo Formation in South China as the youngest constraint on the onset of the Marinoan glaciation, demonstrating that the Cryogenian nonglacial interlude lasted for at least 9 m.y. and the Marinoan glaciation was <17 m.y. long. Cryogenian glaciation in western Laurentia occurred against the backdrop of -85 m.y. of episodic rift-related subsidence and magmatism within laterally discontinuous, fault-bound basins. [ABSTRACT FROM AUTHOR]

Seismic-reflection surveys of the Isle Royale sub-basin, central Lake Superior, reveal two large end moraines and associated glacial sediments deposited during the last cycle of the Laurentide Ice Sheet in the basin. The Isle Royale moraines directly overlie bedrock and are cored with dense, acoustically massive till intercalated down-ice with acoustically stratified outwash. Till and outwash are overlain by glacial varves, a lower red unit and an upper gray unit. The maximum extent of late Younger Dryas-age readvance into the western Lake Superior basin is uncertain, but it was probably controlled by both ice dynamics and climate. Our data indicate that during retreat from the maximum, the ice paused just long enough to construct the outer of the two moraines, >100 m high, and then retreated to the inner moraine, during which time most of the lower glacial-lacustrine sequence (red varves) was deposited. Retreat from the inner moraine coincided with a marked flux of icebergs at the calving margin and a change to gray varves. Rapid retreat may be related to both an influx of meltwater from Glacial Lake Agassiz about 10,500 cal yr BP and retreat of the calving margin down an adverse slope into the Isle Royale sub-basin. [ABSTRACT FROM AUTHOR]

Many formerly glaciated valleys in the western United States preserve detailed glacial features that span the penultimate glaciation through the last deglaciation; however, numerical age control is limited in many of these systems. We report 35 new cosmogenic 10Be surface exposure ages of moraine boulders in the Sawatch Range, Colorado. Eight ages suggest Bull Lake moraines in Lake Creek (range: 132–120 ka, n = 4) and Clear Creek (range: 187–133 ka, n = 4) valleys may correlate with Marine Isotope Stage 6. In Lake Creek valley, 22 10Be ages from Pinedale end moraines average 20.6 ± 0.6 ka, and 5 10Be ages from a recessional moraine average 15.6 ± 0.7 ka, indicating that glaciers occupied two extended positions at ~21–20 and ~16 ka. The glacial extent dated to ~16 ka was nearly as great as that of the earlier glacial phase, suggesting that climate conditions in the Colorado Rocky Mountains at this time were similar to those of the last glacial maximum. Combining these moraine ages with seven previously published 10Be ages from cirque and valley-bottom bedrock reveals that the Lake Creek paleoglacier lost 82% of its full glacial length in ~1.5 ka and was completely deglaciated by ~14 ka. [ABSTRACT FROM AUTHOR]

The Laurentide Ice Sheet of the last glacial period terminated in several lobes along its southern margin. The timing of maximum extent may have varied among the terminal lobes owing to internal ice sheet dynamics and spatially variable external controls. Some terminal ice lobes, such as the westernmost James Lobe, remain poorly dated. To determine the timing of maximum ice extent in this key location, we have mapped glacial deposits left by the Pierre Sublobe in South Dakota and applied 10Be surface exposure age dating on boulders on moraine ridges associated with three distinct late Quaternary glacial drifts. The oldest and most extensive "Tazewell" drift produced variable 10Be surface exposure ages spanning 20–7 ka; the large range is likely attributable to moraine degradation and subsequent boulder exhumation. The oldest ages of about 20 ka are probably limiting minimum ages for the Tazewell moraine surfaces. By contrast, exposure ages of the youngest "Mankato" drift of the easternmost Pierre Sublobe tightly cluster at about 16 ka. This age for the Pierre Sublobe is consistent with the nearby Des Moines Lobe, suggesting both acted together. [ABSTRACT FROM AUTHOR]

In this study, we reconstruct the style and timing of the late Quaternary glaciation pattern in a monsoon‐influenced precipitation‐deprived region (Dhauliganga basin) of the Central Himalaya, India. We present detailed glacial geomorphological mapping, aided by topographic maps, satellite data, Google Earth images, global positioning system survey, and fieldwork (2012–2016), supported by optically stimulated luminescence dating. Our estimations for the magnitude and timing of glaciations in the Dunagiri Glacier valley suggest five sets of glacial advances. The oldest and most extensive glaciation in the valley is Dunagiri Glacial Stage‐I (DGS‐I), represented by a discontinuous moraine ridge that extends down to ~10 km (~2700 m a.s.l.) from the present‐day snout and formed 13±3 ka ago. The DGS‐II stage is present in the form of a small moraine ridge (~3000 m a.s.l.) that formed 10±2 ka ago. The DGS‐III and DGS‐IV glacial stages are 5–6 and 3.5 ka old, respectively. The youngest stage (DGS‐V) of glaciation belongs to the neoglaciation episode ~1 ka old. DGS‐I was the most extensive glaciation in the valley and corresponds to the global Last Glacial Maximum. The glaciation pattern has been correlated with the estimates of present‐day glacial sensitivity to climate and explained as forcing factors sensitive to temperature and/or precipitation changes in the region. The observations based on prevailing climate correlations aided with available glacial chronologies underline the fact that the glacial valleys situated in precipitation‐deprived regions have preserved a delayed response of glaciations to regional climatic events. Estimates for the timing and pattern of glaciation in the present study suggest a different glacial response for modern climatic changes than previously assumed. We suggest that individual glacier advances differ regionally and, therefore, should not be interpreted as being reflective of a change in the whole geographical belt. [ABSTRACT FROM AUTHOR]

Located in the Eastern Anatolian Region in Turkey, the Munzur Mountains (Munzurs; 3463 m above sea level) are one of the most important glacial landscapes in Turkey, with evidence for extensive glaciations in the past and small-scale glaciation at present. As Turkey's second-largest glaciated region, these mountains include various glacial landforms, primarily glacial valleys, hanging valleys, cirques, and moraines. However, only limited data are available on the extent and chronology of former glaciations in the Munzur Mountains. This study produced data on the extent of paleoglaciers, calculated their equilibrium line altitudes (ELAs), revealed paleoclimate conditions, and modeled paleo temperatures during maximum ice extent using numerically derived reconstruction methods (GlaRe and ELA calculation tools) based on geomorphic evidence. The major glacial landforms were first mapped in detail before the reconstruction. Six hundred and eighty cirques and 30 glaciated valleys were identified. Paleoglaciers did not override the entire mountains, however, valley glaciers converged where topographic conditions were suitable. The maximum extent of glaciation covered an area of ca. 600 km2. The largest glacier was ca. 19 km in length. Moreover, 15 of the valley glaciers were over 10 km in length. Their average thickness was 75 m, and the maximum glacial thickness, in the Eastern Munzurs, was found to be ca. 300 m. The total volume of ice reached ca. 45 km3. The paleoglaciers reached as low as 1350 m above sea level. The average ELA was calculated approximately 2600 m above sea level, indicating an equilibrium line altitude depression of 1000-1100 m. The paleotemperatures, estimated based on different scenarios at the time of the maximum extent of Munzur glaciers, were 8-10 °C lower than today. The mountains experienced an increase in precipitation through this period with respect to the current precipitation scheme. [ABSTRACT FROM AUTHOR]

The Kellerjoch forms a small isolated massif at the northernmost rim of the central Eastern Alps of Tyrol and shows a number of geomorphological features of glacial and periglacial origin. Mapping yields evidence of two local glaciations postdating the Last Glacial Maximum. Using a simple glaciological approach the palaeoglaciers related to these events were reconstructed. The older glaciation yields an equilibrium line altitude (ELA) ranging from 1660 m for the maximum extent to 1800 m a.s.l. for the innermost moraine. For the younger glaciation, ELAs were reconstructed at 1905 m and 1980 m (depending on the reconstruction) for the Kellerjoch palaeoglacier 2, as well as 1870 m and 2060 m a.s.l. for the Proxen palaeoglacier and the Gart palaeoglacier, respectively. A comparison with published data from the Eastern Alps shows that the older glaciation in the Kellerjoch region likely corresponds to the Gschnitz stadial. Low basal shear stresses of the glacier tongues point towards a cold and dry climate, similar to the reconstruction for the Gschnitz type locality at Trins. The younger glaciation cannot unambiguously be assigned to a specific Late Glacial ice advance, but a Younger Dryas age is a distinct possibility. [ABSTRACT FROM AUTHOR]

Geomorphological and geological mapping have long been used to study the glacial history of the Slovenian Alps, but many uncertainties remain regarding the time and extent of Pleistocene glaciations there. Glacial landforms and undisturbed glacial deposits are rare in the areas of the former glacier terminus, especially in the Soča Valley, where large discrepancies in the interpretation of the extent of the former Soča Glacier have been reported. Early studies proved inconclusive as to whether one or two glaciations extended into the Soča Valley as far as Most na Soči. In order to answer this question, the Quaternary sedimentary succession and landforms in the Modrejce Valley near Most na Soči were investigated. New geological and geomorphological field data allow the interpretation of the sedimentary environment and the stratigraphic relationships between different units. In response to glacial dynamics, the sedimentation developed from glaciofluvial and glaciolacustrine to fully glacial environments, followed by slope deposition. At higher altitudes lateral moraines are preserved, while the staircase-like slope below has been carved into older glacial, glaciofluvial and glaciolacustrine deposits by glacial and post-glacial processes, including fluvial erosion and slope dynamics. We conclude that the succession studied here was deposited over the course of two different glacial advances – LGM and pre-LGM. Our study thus suggests that the Soča Glacier extended as far as the area of Most na Soči twice over the course of the late Quaternary. [ABSTRACT FROM AUTHOR]

Exhumed Paleozoic glacial deposits and landforms of the North Gondwana are reported here for the first time from the South Eastern Desert (SED) of Egypt. Using field observations and remote sensing datasets (Advanced Land Observing Satellite [ALOS], Phased Array L-band Synthetic Aperture Radar [PALSAR] radar, multispectral Landsat TM datasets, and digital elevation models [DEMs]), we mapped the distribution of Paleozoic glacial features (i.e. deposits and landforms) in the SED. Two main glaciogenic facies were identified in three locations in the SED: (1) massive, poorly sorted, matrix supported, boulder-rich diamictites in Wadi El-Naam and Korbiai, and (2) moderately-sorted, occasionally bedded outwash deposits in Betan area. Inspection of radar, DEMs, and Landsat Operational Land Imager (OLI) images revealed previously unrecognized ENE-WSW trending glacial megalineations (MLs) over the peneplained Neoproterozoic basement rocks in the central sections of the SED, whose trends align along their projected extension with those of glacial features (tunnel valleys and striation trends) reported from Saudi Arabia. The glaciogenic features in the SED are believed to be largely eroded during the uplift associated with the Red Sea opening, except for those preserved as basal units beneath the Nubia Sandstone Formation or as remnant isolated deposits within paleo-depressions within the basement complex. The apparent spatial correlation of the SED glacial features with well-defined Late Ordovician deposits in North Africa and in Saudi Arabia, and the reported thermochronometric analyses and fossil records are consistent with a Late Ordovician age for the SED glaciogenic features and support models that call on the continuation of the Late Ordovician (Hirnantian) ice sheet from the Sahara into Arabia through the SED of Egypt. [ABSTRACT FROM AUTHOR]

The article presents findings related to the geologic evidence of a cool climate teetering on the edge of global glaciation several million years before the Sturtian Snowball Earth. It presents the eruption ages for three felsic volcanic units interbedded with glaciolacustrine sedimentary rocks that demonstrate that glacially influenced sedimentation occurred at tropical latitudes.

Knowledge of the glacial chronologies for the Last Glacial Maximum (LGM) helps in understanding the interactions between climate, topography and glacier development. In this sense, the investigation of the Lake Orta moraine amphitheatre (Alpine foreland, northern Italy) allowed spatial and temporal reconstruction of the Orta Glacier. The end‐moraine system was investigated by means of geomorphological field surveys, analysis of 13 rock samples for cosmogenic 10Be and 36Cl concentrations, and remote sensing analysis. The dating results indicate that the age of the outer moraine belt is concordant with the LGM culmination at 26.5–23 ka, as found in other amphitheatres in the Alps. This new age estimate of the outermost moraines shows that the maximum extent of the Orta Glacier during the LGM was significantly bigger than recently suggested. A younger stabilization phase of the glacier front at about 19 ka indicates that the onset of the withdrawal of glaciers from the lower Alpine valleys started later. Provenance analysis of the boulders shows that the greatest contribution of ice to the Orta Glacier came from the Anzasca Valley rather than the major Ossola Valley. This reflects the closeness (about 45 km) to the foreland of the high‐elevated accumulation area of the Monte Rosa massif (4634 m a.s.l.), whose eastern glacier seems to have reached the lower valley faster than the trunk Toce Glacier. This fact underlines the key role played by high‐elevation accumulation areas that are located close to the foreland in controlling the path and geometry of major glaciers in the Alps. [ABSTRACT FROM AUTHOR]

The age and origin of the Grover Gravel, which is preserved on stable uplands in St. Louis County, Missouri, USA, and similar gravels along the Mississippi River bluffs farther south, have been controversial for over a century. These gravels have some features consistent with a glacial origin but lack obvious erratics such as igneous rock fragments. New observations, however, show that the earliest tills within the Mississippi basin nearly lack such constituents as well, and that the Grover Gravel is a Pleistocene deposit derived from such a till. A Mississippi River terrace deposit in St. Louis County also includes typical clasts of this till and formed between 2.0–1.8 Ma, based on various dating methods. This deposit may correspond to a pulse of glacial meltwater recorded within sediment near the mouth of the Mississippi River and represent outwash from a previously unrecognized glaciation within the US midcontinent. The Mounds Gravel (or Upland Complex) is present farther south around the perimeter of the Mississippi Embayment and contains the same distinct clasts as the gravels in St. Louis County. Given that the age of the Mounds is <~3 Ma based on cosmogenic‐nuclide ratios, the southern gravel could be the same age as the gravel terrace in St. Louis County. If so, these gravels could mark a geomorphic transition to glacial‐dominated sedimentation farther south in and around the Gulf of Mexico. Regardless, all the upland gravels have insignificant amounts of zircon from provinces west of Hudson Bay. Therefore, detrital zircon provenance does not support a recent hypothesis that the Mounds (Upland Complex) was deposited by a giant Mississippi River with a drainage basin extending across broad areas west of Hudson Bay. [ABSTRACT FROM AUTHOR]

The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee (Li Siguang) discovered Quaternary glacial relics at Taihang Mountainin eastern China. In 1947, he published his research findings in the magazine Mount Lushan in Glacial Age. The research results had established three Ice Ages: Poyang (Gonzi), Dagu (Minde), and Lushan (Lisi). However, at that time, no Wurm glacial relics of the last Ice Age had been found in Lushan Mountain. Since then, the research team represented by Shi Yafeng, who is considered to be "the father of glaciers in China", questioned Jonquei S. Lee's research results and concluded that "Professor Jonquei S. Lee's Quaternary glacier research in Lushan Mountain having misread the debris flow". In 2005, the "middle‐low mountains" in eastern China were finally defined as follows: "We clearly and unambiguously believe that there were no glacial activities in the middle‐low mountainous areas of eastern China (east of 102° to 104°E; below 3,000 and 2,500 m) during the Quaternary Period". Currently, the long‐standing academic debate appears to have come to a conclusion. As of 2015, the author and others began to investigate and study the Quaternary glacial relics in Mengshan Mountain (1,156m above sea level), Shandong Province, one of the "middle‐low mountains" of eastern China. The relics have been observed to posses the systematic features of glacial erosion, trough and valley striations, and moraine deposits. The applied dating method shave confirmed that there were not only glacial relics of the last Ice Age (Wurm), but also Holocene glacial relics in the Mengshan Mountain area. Therefore, in order to further establish the corresponding relationship between the glacier, loess, stream sediment series, and MIS in the Mengshan Mountain area, a large number of chronological studies have been carried out regarding the various types of sediments in the area, and 24 dating datahave been obtained using OSL, CRN, and 14Cmethods. On this basis, the corresponding relationship between the sedimentary sequences and the MIS was established for the first time in eastern China, which in dicates the environmental changes which had occurred in eastern China since 80ka. These discoveries s and chronological study results confirm the existence of the Last Ice Age, as well as Holocene glacial relics at Mengshan Mountain, there by confirming that Quaternary glaciation had occurred in the middle‐low mountain areas of eastern China. [ABSTRACT FROM AUTHOR]

Mount Achernar moraine is a terrestrial sediment archive that preserves a record of ice-sheet dynamics and climate over multiple glacial cycles. Similar records exist in other blue ice moraines elsewhere on the continent, but an understanding of how these moraines form is limited. We propose a model to explain the formation of extensive, coherent blue ice moraine sequences based on the integration of ground-penetrating radar (GPR) data with ice velocity and surface exposure ages. GPR transects (100 and 25 MHz) both perpendicular and parallel to moraine ridges at Mount Achernar reveal an internal structure defined by alternating relatively clean ice and steeply dipping debris bands extending to depth, and where visible, to the underlying bedrock surface. Sediment is carried to the surface from depth along these debris bands, and sublimates out of the ice, accumulating over time (>300 ka). The internal pattern of dipping reflectors, combined with increasing surface exposure ages, suggest sequential exposure of the sediment where ice and debris accretes laterally to form the moraine. Subsurface structure varies across the moraine and can be linked to changes in basal entrainment conditions. We speculate that higher concentrations of debris may have been entrained in the ice during colder glacial periods or entrained more proximal to the moraine sequence. [ABSTRACT FROM AUTHOR]