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Nivation, the suite of weathering and transportation processes attributed to late-lying snowpatches, is linked to the formation of cryoplanation terraces (CTs). CTs resemble giant staircases arranged in repeating sequences of low-gradient treads and steep scarps that extend over hundreds of meters. The nivation hypothesis of CT development has been supported in recent literature examining weathering and erosion trends, but the mechanisms involved in transporting sediment across CT treads remain underinvestigated. Sorted stripes, a type of patterned ground encountered on CT treads, have been linked to efficient snow meltwater flow across low gradients, indicating that these features could be an important component of CT formation. In this study, we use short-term soil thermal and moisture records, particle-size analysis, and apparent thermal diffusivity calculations to examine periglacial processes operating on two incipient CTs. Initial results indicate that: (1) the coarse (boulder and cobble size) portions of sorted stripes function as subsurface channels for sediment transportation across gently sloping CT treads (generally < 12°) by flowing water; (2) hillslope hydrology is an important component of the erosion processes sculpting upland periglacial environments; and (3) late-lying snowbank environments are highly dynamic during warm weather, with large amounts of sediment transported over short periods. [ABSTRACT FROM AUTHOR]

An extraordinary variation of plastic and brittle deformation structures with periglacial, glaciotectonic and seismic features was observed within the unconsolidated, upper Pleistocene meandering river succession in the Slinkis outcrop in central Lithuania. Among these deformations, the following structures were described: (1) ice-wedge casts in the lower part of the sedimentary succession, linked to periglacial processes, (2) soft-sediment deformation structures, such as load structures (load casts, pseudonodules), flame structures and water/sediment-escape structures, all trapped in clearly defined layers in the upper part of the sedimentary succession, which are related to the propagation of seismic waves, and (3) faults occurring throughout the sedimentary succession, which are associated with glaciotectonic processes. To our knowledge, this is the first description and analysis of the combined presence of such a diverse range of deformation features caused by three trigger mechanisms in a meandering fluvial sedimentary succession. [ABSTRACT FROM AUTHOR]

Abstract Fluvial terraces in the upper Hunter catchment, southeastern Australia provide a long-term record of river activity in response to climate change in the late Quaternary. Single-grain optically stimulated luminescence (OSL) dating of quartz was applied in this study to investigate the timing of the formation of three fluvial terraces in the upper Hunter catchment. A detailed examination of luminescence properties of individual quartz grains revealed some correlation between their OSL decay rates, intrinsic brightness and dose saturation characteristics. Some quartz grains containing a higher proportion of non-fast components exhibit low brightness in OSL signals and high dose saturation levels. Some grains with slow OSL decays pass the standard rejection criteria, but are likely to yield underestimated equivalent doses (D e s) because of a higher contribution of non-fast components, which are shown to have low thermal stability. Different rejection criteria, including the fast ratio, the dose saturation level and the OSL sensitivity criteria, were tested on the single-grain D e results. Application of a fast ratio rejection criterion is able to successfully identify thermally unstable grains. A new rejection criterion based on dose saturation property was also applied to improve the age of one sample with a large D e. Our dating results identify multiple phases of river valley aggradation in the upper Hunter catchment since late Marine Isotope Stage (MIS) 6; at ∼ 138 ka, ∼90–94 ka, ∼65 ka, ∼26 ka and ∼18 ka. The aggradational episodes of the terraces in the upper Hunter catchment are correlated with glacial or stadial periods since MIS 6. These phases of valley-floor aggradation are inferred to be a function of increased sediment supply during the cold periods resulting from strong periglacial activities in the adjacent Australian highlands. Highlights • We optically dated three fluvial terraces in the upper Hunter catchment, SE Australia. • We found a linkage between multiple luminescence properties for single quartz grains. • Application of additional SG rejection criteria can improve the SG OSL dating results. • Terraces in the upper Hunter catchment aggraded in glacial or stadial episodes. • Terrace aggradation may result from strong periglacial activities during cold periods. [ABSTRACT FROM AUTHOR]

In connection with the future Seine-North Europe Canal (Seine-Scheldt), a large-scale rescue archaeological survey was conducted at Havrincourt (northern France) between 2008 and 2011. The discovery of several levels of Palaeolithic flint artefacts embedded in a relatively thick loess sequence (ca 6–7 m) preserved on a gentle slope facing North-East, resulted in a 6000 m 2 excavation. This opened the opportunity for a detailed pedosedimentary and interdisciplinary geochronological survey ( 14 C, optically stimulated luminescence, thermoluminescence, ESR/U-series) that has allowed us date the sequence reliably. On the basis of these results we propose this sequence as a new pedostratigraphic and archaeological reference sequence for northern France. We present here the optical dating of the sequence performed on fine (4–11 μm) quartz grains extracted from 17 samples. The luminescence characteristics of these extracts indicate that the single-aliquot regenerative dose optically stimulated luminescence (SAR-OSL) procedure that was applied is well suited. A consistent set of optical ages was obtained for the loess deposited up to around 70 ka ago. Independent age control (pedostratigraphy, 14 C, ESR/U-series dates) allowed us to apply a Bayesian approach to build a chronometric model. This in turn enabled a regional chronostratigraphic framework to be built, to constrain the correlations with neighboring regions (northern France and Belgium) and to calculate a precise age for the four Palaeolithic levels discovered, including a unique occupation related to the early Upper Palaeolithic which was previously unknown in the area. [ABSTRACT FROM AUTHOR]

Till macrofabric and grain-size analysis of glacial diamictons and sequences present in several valleys of the Serra do Gerês Mountains in the Northwestern Iberian Peninsula were used to interpret till types and to reconstruct the glacial paleoprocess history of this mountainous region. Subglacial lodgement, supraglacial melt-out, and deformation tills are dominant in this range. Subglacial lodgement tills, representative of periods of glacial advance followed by stability in several valleys, present cluster fabrics and generally poorly sorted and fine sediments. Supraglacial melt-out and deformation tills, representative of periods of glacial stability with some minor readvances followed by recession, present weaker fabric data and coarser, poorly sorted sediments. Glacial deposits affected by post-glacial paraglacial activity in the form of landslides were also observed in one valley. These present weaker to moderate fabric data and coarser, poorly sorted sediments. These glacial diamictons and sequences are of particular importance in the reconstruction of the glacial dynamics and history of the Serra do Gerês Mountains due to poor preservation of glacial landforms related to the Last Glacial Maximum in several glaciated valleys. [ABSTRACT FROM PUBLISHER]

The Malše River, on the border between Austria and the Czech Republic, contains one of the last remaining freshwater pearl mussel (Margaritifera margaritifera) populations on the Bohemian Massif. Evidence from field studies indicated that landscape evolutionary processes changed the boundary conditions for river channel formations, especially in those parts where the remaining mussels, probably also self-reproducing to a limited extent, were documented. The aim of the present work was to study these possible palaeo-impacts through (i) the analysis of the terrain data and accompanying hydrodynamic-numerical modelling and (ii) sediment sampling of the main channel and the surrounding floodplains at the reach and catchment scales. The results indicated that solifluction caused a historic blockage in the drainage area with consequent formation of lakes in the upstream part of these obstructions. At least two sites where this "Wullowitz-Lakes Theory" can be applied were identified. The occurrence of these lakes was validated by sediment analysis. The findings further indicated that the later fluvial processes in these deposits of a former stagnant water body forced the formation of an anabranching channel in the system, which would not have occurred in a solely freely developed fluvial system. In conclusion, it could be determined that the consideration of palaeo-processes might be important even for present onsite assessments of aquatic habitats and species such as the endangered freshwater pearl mussel. [ABSTRACT FROM AUTHOR]

Catastrophic drainage of ice-dammed lakes in the Altai Mountains has been inferred from geomorphological evidence in the Katun Valley (Russia), and is presumed to have occurred during the Pleistocene. The sedimentary features have been difficult to date directly, due to the absence of organic carbon, and the improbability that luminescence signals in sand grains would be reset during transport. However, the development of rock-surface luminescence dating provides a new opportunity to date the features: clasts have a different transport history to sand grains, and their luminescence depth profiles can be inspected for evidence of bleaching before burial. Here we investigate two sites in the Altai Mountains, and use rock-surface luminescence burial dating to constrain the age of the megaflood deposits. In the Katun Valley, we sampled granite cobbles from a frozen sediment clast emplaced as a dropstone within a massive megaflood gravel terrace. Burial ages for the clasts range from 16.7 to 21.4 ka, with a mean age of 19.8 ± 1.5 ka. This represents the depositional age of the fluvial sediments that preceded the lake outburst flood, (and hence places a maximum age on the catastrophic flood). Clasts sampled from mega-ripples in the Kurai Basin are shown to have a mid-to-late Holocene burial age, which is not consistent with the possible origin of these features during a catastrophic drainage of a glacier-dammed lake. Instead, the burial age of the Kurai Basin sediments may reflect local-scale periglacial or seismic processes along the Kurai Fault Zone. [ABSTRACT FROM AUTHOR]

In the Iberian Chains of northeastern Spain, the Hirnantian Orea Shale comprises three erosive glaciogenic unconformities punctuating two transgressive glaciomarine sequences. These sequences represent ice retreat episodes of grounded ice on a North Gondwanan region of 50–60°S of estimated palaeolatitude. In contrast, the same formation recorded in the Hesperian Chains repeated episodes of extensional tectonic activity: diamictites were associated with slope-related debris flows and slumps commonly interrupted by truncating discontinuities. An analysis of δ 13 C org in the Orea Shale has revealed that the lower Orea sequence displays isotopically light baseline values (∼ −27‰) punctuated by minor (2–3‰) shifts. In distal parts, the upper sequence is characterised by a rapid rise in δ 13 C org values, which mark a positive excursion, in the range of 2.5‰ to 7‰ over 40 cm of thickness. The stratigraphic gap involved in the intra-Orea erosive unconformity appears to be greater both in proximal exposures and slope-related (Hesperian) areas, where the chemostratigraphic shift was not recorded. Upsection in the three studied sections, the δ 13 C values display upsection a sharp return to baseline values of −26‰ to −28‰. The Hirnantian strata of the Iberian and Hesperian Chains have recorded three major correlatable events: (i) a the karstic surface that caps upper Katian limestones and reflects the maximum glacial extension; (ii) a single δ 13 C org positive peak of ∼6‰ that is recognisable in distal ramp settings, marking the beginning of the second ice retreat episode and probably representing the late Hirnantian HICE shift; and (iii) the erosive unconformity marked by the progradation of the Los Puertos shoreline complexes. [ABSTRACT FROM AUTHOR]

Glacial isostatic adjustment (GIA) is the Earth's adjustment to the shift in mass due to melting ice sheets, which results in horizontal and vertical motion over the entire surface of the Earth. The Earth has been gradually adjusting since the last glacial maximum, around 22,000 yr ago. Areas with significant current post glacial adjustment include Fennoscandia, (Norway, Finland, and Sweden) Canada, Northern Europe, Patagonia, and Antarctica. By studying GIA, scientist are able to collect data on the viscosity of the mantle, the thickness of the lithosphere, the change in mass of ice sheets, as well as estimate sea-level trends. [ABSTRACT FROM AUTHOR]

To elucidate the Middle and Late Pleistocene environmental history of south-central England, we report the stratigraphy, sedimentology, palaeoecology and geochronology of some deposits near the foot of the Chiltern Hills scarp at Marsworth, Buckinghamshire. The Marsworth site is important because its sedimentary sequences contain a rich record of warm stages and cold stages, and it lies close to the Anglian glacial limit. Critical to its history are the origin and age of a brown pebbly silty clay (diamicton) previously interpreted as weathered till. The deposits described infill a river channel incised into chalk bedrock. They comprise clayey, silty and gravelly sediments, many containing locally derived chalk and some with molluscan, ostracod and vertebrate remains. Most of the deposits are readily attributed to periglacial and fluvial processes, and some are dated by optically stimulated luminescence to Marine Isotope Stage (MIS) 6. Although our sedimentological data do not discriminate between a glacial or periglacial interpretation of the diamicton, amino-acid dating of three molluscan taxa from beneath it indicates that it is younger than MIS 9 and older than MIS 5e. This makes a glacial interpretation unlikely, and we interpret the diamicton as a periglacial slope deposit. The Pleistocene history reconstructed for Marsworth identifies four key elements: (1) Anglian glaciation during MIS 12 closely approached Marsworth, introducing far-travelled pebbles such as Rhaxella chert and possibly some fine sand minerals into the area. (2) Interglacial environments inferred from fluvial sediments during MIS 7 varied from fully interglacial conditions during sub-stages 7e and 7c, cool temperate conditions during sub-stage 7b or 7a, temperate conditions similar to those today in central England towards the end of the interglacial, and cool temperate conditions during sub-stage 7a. (3) Periglacial activity during MIS 6 involved thermal contraction cracking, permafrost development, fracturing of chalk bedrock, fluvial activity, slopewash, mass movement and deposition of loess and coversand. (4) Fully interglacial conditions during sub-stage 5e led to renewed fluvial activity, soil formation and acidic weathering. [ABSTRACT FROM AUTHOR]

The combined usage of till-fabric and grain-size analysis in the sedimentological interpretation of glacial diamictons allows the reconstruction of the processes responsible for the genesis of certain moraines. Till-fabric and grain-size data from several late Quaternary moraines present in three glacial valleys of the Serra da Peneda Mountains in northwestern Portugal revealed the presence of two types of till deposited during several stages. During the first stage, ice advanced into the lower Alto Vez and Branda da Junqueira valleys and deposited the lodgment tills present in the Alto Vez moraine 1 (unit 1) and Branda da Junqueira moraine; therefore, these features are interpreted to initially be lateral-terminal and lateral push moraines, respectively. Subsequent stages of glacial stability followed by recession in the Alto Vez and Rio Pomba lower valleys deposited the supraglacial melt-out tills (ablation tills) present in the Alto Vez moraines 1 (unit 2), 2, and 3 and the Rio Pomba moraine. These four landforms are interpreted to be lateral-terminal, lateral, lateral-recessional and recessional ablation moraines, respectively. The Alto Vez moraine 1 had two constructional events, starting most likely as a lateral-terminal push moraine and ending as a lateral-terminal ablation moraine. [ABSTRACT FROM AUTHOR]

Recently, the investigation of Mars is carried Out by space probes. Satellite images, DEMs and other types of planetary datasets can be integrated and analyzed in GIS software environment. I have investigated two groups of water ice-related Martian slope landforms in eight study areas. The periglacial debris aprons of mid-latitudinal regions developed in the last few hundred million years, as a result of the slow downslope movement and plastic deformation of rock-ice mixtures with cemented inner structure. Nowadays these are inactive or fossil landforms, indicating different climatic conditions in the past. The dark slope streaks on the dune fields of the sub-polar regions are the surface signatures of the pore volume-filling downslope seepage of liquid interfacial H2O, originating from the near-surface material in recent spring/summer periods. These two different types of ice-related slope landforms can be explained by the same process: partial melting of water ice in the shallow subsurface layers. Therefore, both can be considered as reliable locations and reachable sources of H2O reservoirs to be found on the planet. [ABSTRACT FROM AUTHOR]

Abstract: Cosmogenic nuclide surface exposure ages are determined from in situ 10Be and 36Cl analysis of 38 rock surfaces found in different glacial landforms in Denmark. Dating of erratic boulders and adjacent ice-sculpted bedrock on the island of Bornholm in the western Baltic Sea reveals almost identical values. This suggests that little if any inherited nuclides are present in the sampled boulders. West of the Last Glacial Maximum (LGM) ice margin in Denmark ages reflect exposure from the Middle Weichselian. East of the LGM margin exposure ages from 35 samples show Late Weichselian ages in a range between 20.6–11.9 ka. To test to what extent these dates reflect the onset of deglaciation immediately after cessation of active glacier flow, surface exposure ages are evaluated against independent chronologies of Late Weichselian ice-sheet fluctuations in southwestern Scandinavia. The Bornholm dates agree with the independent age model, however, in the data set for eastern Denmark only less than half the surface exposure ages lie within the expected age envelope. This apparent mismatch is most likely due to post-glaciation shielding and delayed surface stabilisation compared to the timing of ice-margin retreat. Thus ages from boulders resting in dead-ice moraines and mass wasting landscapes underestimate deglaciation by 3–6 thousand years. The results quantify the impact of exhumation and landform stabilisation on cosmogenic surface exposure ages on millennial scales. We conclude, that interpretation of cosmogenic exposure ages should include careful evaluation of possible post-depositional landform transformation in attempts to fine tune ages of e.g. end moraine features. With reference to independent age models we critically evaluate glacier advance – retreat scenarios from regions around the southern Baltic that alone are based on weighted average ages of cosmogenic exposure dating. [Copyright &y& Elsevier]

Abstract: Drowned landscapes are important archives documenting palaeoenvironmental response to abrupt climate and sea-level changes characteristic of the Quaternary. Analysis of high resolution geophysical and core data has revealed preservation of fluvial, coastal, shallow marine and periglacial deposits on the continental shelf in the eastern English Channel, thus providing an ideal field site to test the application of optical dating to a variety of depositional environments presently submerged beneath the sea. A stratigraphic model detailing the sequence and nature of sedimentary processes operating on the shelf in relation to post-glacial relative sea-level change is presented as a framework to test the reliability of optical ages. The single-aliquot regenerative-dose protocol was applied to 1 mm aliquots of fine quartz sand and individual aliquots were rejected following the criteria proposed by Wintle and Murray (2006). All samples demonstrate a range of intrinsic sensitivities with a sufficient number of grains giving enough light to enable reliable estimation of D e. Different age models, CAM and MAM-3, were used to establish palaeodose and the robustness of these age models was tested using a bootstrapping technique. Coastal sediments show evidence of incomplete bleaching limiting confidence in age estimates. Quartz deposited in fluvial, periglacial and shallow marine environments is suitably bleached and OSL sensitive to enable reliable estimates of D e. Changes in environmental dose must be considered when interpreting ages from sediments that have experienced repeated relative sea-level cycles. Ages in the range of 107.8 ka to 5.3 ka were calculated that are remarkably consistent with the stratigraphic model, thus demonstrating the successful applicability of optical dating to drowned landscapes. [Copyright &y& Elsevier]

Abstract: An up to 15 m thick alluvial fan and aeolian sandsheet complex is exposed in the upper Senne area, on the southern slope of the Teutoburger Wald Mountains (NW Germany). The origin and age of these deposits have been controversially discussed for many years, ranging from Saalian glaciofluvial to periglacial Weichselian deposits. In order to provide a high-resolution chronological framework for the deposits, we conducted luminescence dating of 12 samples from two localities (Oerlinghausen and Augustdorf pits). Both coarse-grain potassium-rich feldspar and quartz minerals were used for luminescence dating. Feldspar was measured using an elevated temperature post-IR infrared stimulated luminescence (IRSL). Quartz was measured using optically stimulated luminescence (OSL) with a conventional single aliquot regenerative dose (SAR) protocol. Feldspar results tend to overestimate quartz ages for the lower part of the sections (alluvial plain and alluvial fan facies) but are consistent with quartz ages for the upper part of the sections (aeolian facies). Quartz ages from both central and minimum age models suggest deposition during the Late Pleistocene Pleniglacial to Late Glacial. [Copyright &y& Elsevier]

Abstract: We consider the formation of the Dal’nii (Dal’nyaya) eluvial gold placer (Bol’shoi Anyui ore–placer district, western Chukchi Peninsula), related to the Dal’nii (Dal’nee) gold-bearing porphyry Mo–Cu occurrence. The Dal’nii placer is located within the transition between the Kur’ya Ridge and Anyui basin, which has been relatively stable at the recent (Pliocene–Quaternary) tectonic stage. Minor recent uplift has determined the slight denudation of interfluves, the leading role of eluvial processes in the formation of a loose cover on them, and the preservation of the relict matter of pre-Pliocene chemical-weathering crusts (including the oxidized zones of orebodies) in present-day eluvium. The Dal’nii placer consists of relict weathering-crust placers altered by recent eluvial processes in different degrees. Therefore, it is relatively rich in metal, whereas the primary lode contains mainly fine-sized gold, which is almost not released from ore under periglacial lithogenesis in present-day interfluves. We suggest calling this genetic type of placers “residual-eluvial.” The primary lodes being highly eroded (during the formation of residual concentrations, which serve as an intermediate reservoir for these placers), residual-eluvial placers or their parts might not be directly related to specific orebodies at the present-day level of erosional truncation. [Copyright &y& Elsevier]

Abstract: Relict periglacial wedge structures are widespread in mid-latitude and polar regions. The wedges have a high preservation potential and are often infilled with quartz-rich aeolian sand, making them potentially suitable for luminescence dating. This paper presents initial work from an anti-syngenetic sand wedge in the Tuktoyaktuk Coastlands, Arctic Canada. When samples were measured at the single grain level they showed poor palaeodose (De) reproducibility and consequent high age uncertainties. The aim of the study was to determine whether this intra-sample De scatter reflected methodological issues arising from OSL measurement or processes of wedge development. Initial single grain dose recovery tests show that De scatter was not easily explained by poor recycling, sensitivity changes, variable OSL components, recuperation problems, or large De uncertainties from dim grains. Single grain preheating tests did show that some De scatter might be attributable to individual grains requiring different preheat temperatures, whilst dose recovery tests revealed that highly sensitive grains showed less scatter than dim grains. However, selection of these bright grains from natural samples still resulted in scattered De values. An alternative explanation for the De scatter relates to the formation of anti-syngenetic sand wedges by thermal contraction cracking over thousands of years in an eroding landscape, which may result in sediment of very different ages being deposited in adjacent cracks. Finite mixture modelling was used to identify De components within each sample. Ages calculated from these components suggest sand wedge formation at ca. 5, 8.5, 12.5 and 18ka which correlate well with known cooling events over the last 18ka and support a multiple phase activity model for anti-syngenetic sand wedges. [Copyright &y& Elsevier]

Abstract: Australian quartz has been widely considered particularly suitable for OSL dating of sediments. We present the results of a preliminary investigation into the luminescence characteristics and behaviour of quartz from various regions and depositional contexts across southeastern Australia. In doing so, we find that quartz from this region is generally well suited to the SAR protocol, although individual sample behaviour should nevertheless be assessed to confirm this. Furthermore, luminescence sensitivity appears to relate to depositional context, with aeolian samples exhibiting the highest sensitivity values, and lacustrine and periglacial sediments the lowest. The extent of a sample''s sedimentary history, which in many cases is characteristic of the region from which it is derived, may also influence quartz sensitisation through repeated cycles of burial and reworking. [Copyright &y& Elsevier]

Periglacial slope deposits (PSD) of Pleistocene age are one of the most widely distributed sediment types in nonglaciated mid-latitude regions. As diamictons of different genesis (geli-solifluction, cryoturbation, eolian transportation) they have a wide range of physical, chemical and mineralogical characteristics which are mainly controlled by bed-rock geology, including saprolite. This paper reviews concepts used in Germany to study PSD stratigraphy and describes the different PSD units encountered (Upper Head, Middle Head, Lower Head). The paper is relevant to the understanding of PSDs in other mid- latitude regions. Classical and new results concerning the age of PSDs show differences in the interpretation of Upper Head genesis. In terms of their ecological significance, case studies from eastern Bavaria illustrate the influence of PSDs on the character and intensity of slope hydrological processes as well as on the formation and distribution of soils. Presently important research questions include (1) the establishment of a genetically based classification of PSDs, (2) the intensification of dating studies on PSDs, and (3) the clarification of hydrological processes in PSDs. [ABSTRACT FROM AUTHOR]