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The island sanctuary of Barrow Island on the edge of the inner North-West continental shelf of Australia holds significant environmental as well as Indigenous and colonial cultural value. Insights on past occupation dynamics, particularly in response to Post-Glacial sea-level rise, continue to emerge from analysis of archaeological assemblages. However, there is limited temporal and landscape information from the wider island with which to better contextualise the physical site formation history of these cultural records. We present a new, modelled Post-Glacial sea-level curve for the region and new geochronological and sedimentological data (including rare earth element and quartz microtextural data) from non-archaeological site contexts to help infer changes in the coastal environment. This new data provides new insights on the island's paleogeography and evolution since approximately 80 ka BP in the context of inherited Last Interglacial features and highly dynamic oceanographic processes. Ongoing physical weathering processes have influenced dune building and reworking, such that neither colour nor numeric age are reliable indicators of sediment compositional and textural maturity. The results continue to emphasise how the continued integration of the island's geological, sedimentological and archaeological records help to understand aspects of cultural site formation, as well as expose some of the limiting factors in our understanding of past and present island physical dynamics. Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version This study was made possible through a Research Collaboration Award from the University of Western Australia, with additional funding provided from an Australian Research Council Discovery Early Career Award to IW (DE180100601). Archaeological data was collected by the Barrow Island Archaeological Project funded by an ARC Discovery Grant (DP130100802) 2013–2015 awarded to PV and team. Department of Biodiversity Conservation and Attractions, Chevron Australia and WA Oil are thanked for their logistical and personnel support in the field, as also are Mick O’Leary and Peter Kendrick. We acknowledge the support of Buurabalayji Thalanyji Aboriginal Corporation. We thank Dick Peltier for providing the ICE-7G_NA ice model and Kurt Lambeck and Anthony Purcell for providing the ANU-ICE ice model. The global ANU-ICE combination model used in this study was kindly provided by Holger Steffen. Tanghua Li is supported by the Singapore Ministry of Education Academic Research Fund MOE2019- T3-1-004 and MOE2018-T2-1-003, the National Research Foundation Singapore, and the Singapore Ministry of Education, under the Research Centers of Excellence initiative. The GIA modelling is conducted in part using the research computing facilities and/or advisory services offered by Information Technology Services, the University of Hong Kong. This work comprises Earth Observatory of Singapore contribution no. 424. The authors also acknowledge the facilities, and the scientific and technical assistance of Microscopy Australia at the Centre for Micro- scopy, Characterisation & Analysis, the University of Western Australia, a facility funded by the University, State and Commonwealth Govern- ments. Acknowledgement is given to Mark Basgall David Zeanah and David Glover of Sacramento University for use of artefact distribution maps; and to Mick O’Leary for the DEM image of the Chair (Loop Beach).

Middle Stone Age (MSA) technologies first appear in the archaeological records of northern, eastern and southern Africa during the Middle Pleistocene epoch. The absence of MSA sites from West Africa limits evaluation of shared behaviours across the continent during the late Middle Pleistocene and the diversity of subsequent regionalized trajectories. Here we present evidence for the late Middle Pleistocene MSA occupation of the West African littoral at Bargny, Senegal, dating to 150 thousand years ago. Palaeoecological evidence suggests that Bargny was a hydrological refugium during the MSA occupation, supporting estuarine conditions during Middle Pleistocene arid phases. The stone tool technology at Bargny presents characteristics widely shared across Africa in the late Middle Pleistocene but which remain uniquely stable in West Africa to the onset of the Holocene. We explore how the persistent habitability of West African environments, including mangroves, contributes to distinctly West African trajectories of behavioural stability. Results - Stratigraphy - Geochronology - Palaeoecology - Stone tool technology Discussion Methods - Excavation - Sedimentology - Geochronology - Palaeoecology - Stone tools

The role of Quaternary ice sheet fluctuations in driving meltwater pulses and ocean circulation perturbations is widely acknowledged. What is less clear is the role of these processes in driving changes in past atmospheric dust activity, and possible wider links between dust and climate. Terrestrial windblown dust (loess) deposits along the northern fringe of the European loess belt potentially record past atmospheric dust emission from regions close to the former Eurasian Ice Sheet (EIS) and provide a means to evaluate the role of ice sheet fluctuations in the past dust cycle. Numerical loess chronologies across this region generally agree on greatly enhanced dust deposition rates during MIS 2, when the EIS reached its maximum extent. Yet, uncertainties over the sources of this material prevent understanding of the precise causes of this greatly enhanced atmospheric dustiness, and any potential link to ice sheet fluctuations and climate. In southeast England, loess accumulation dominantly occurred in two phases centered on 25– 23.5 ka and 20–19 ka, matching the timing of coalescence of the Fennoscandian and British-Irish ice sheets and specifically advances and retreats of nearby ice lobes in the western North Sea. As such, these deposits provide an ideal test of the role of ice sheet fluctuations in atmospheric dust dynamics. Here we undertake such a test through a detailed provenance study of loess in southeast England and potential dust source sediments across the North Sea region. We group extensive new and published data sets of detrital zircon U–Pb ages from basement rocks and Cenozoic sediments in the North Sea area, which not only provide new insight into both loess source, but also the nature of sediment transport over NW Europe into the North Sea basin more widely. Multi-proxy evidence allows us to unambiguously identify ice sheet derived sediments in the exposed North Sea basin as the dominant source of loess in southeast England, while fluvial sediments delivered by rivers draining Continental Europe possibly contributed additional source material to the first loess accumulation phase. We propose that sudden retreats of the North Sea Lobe released substantial amounts of sediment rich meltwater into the southern North Sea and Channel basins, driving accelerated dust emission, loess deposition and provenance variability in NW Europe during MIS 2. Moreover, we propose that this model of dust activity driven by proglacial sediment availability may be applicable for EIS marginal regions more widely, even where resultant loess cover is rarely preserved due to extensive erosion and reworking along the ice marginal spillway. This implies the role of ice sheets in controlling wider dust emission may be underestimated. In addition to driving changes in ocean circulation through meltwater pulses, ice sheet dynamics in the Quaternary may have also driven substantial and abrupt changes in atmospheric dust activity. This mechanism may in part explain the coupling between dust and climate events widely seen in Quaternary dust sediment records and suggests a possible major role of high latitude dust emission in MIS 2 dustiness across Europe and beyond.

Funding information: This work was funded by the Natural Environment Research Council consortium grant BRITICE-CHRONO NE/J009768/1 and by the NERC Radio- carbon Facility and the NERC Cosmogenic Isotope Analysis Facility. The project benefited from the PalGlac team of researchers with funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme to CDC (Grant Agreement No. 787263) and supporting SB and AI. JCE acknowledges support from a NERC independent fellowship award (NE/R014574/1). We thank the PISM team of ice-sheet modellers and Evan Gowan for ICESHEET, and note that the development of PISM was supported by NSF grants PLR- 1603799 and PLR-1644277 and NASA grant NNX17AG65G. DP acknowledges funding from the Italian PNRA project IPY GLAMAR (grant number 2009/A2.15), and from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 656821 (project SEAGAS). The BRITICE‐CHRONO consortium of researchers undertook a dating programme to constrain the timing of advance, maximum extent and retreat of the British–Irish Ice Sheet between 31 000 and 15 000 years before present. The dating campaign across Ireland and Britain and their continental shelves, and across the North Sea included 1500 days of field investigation yielding 18 000 km of marine geophysical data, 377 cores of sea floor sediments, and geomorphological and stratigraphical information at 121 sites on land; generating 690 new geochronometric ages. These findings are reported in 28 publications including synthesis into eight transect reconstructions. Here we build ice sheet‐wide reconstructions consistent with these findings and using retreat patterns and dates for the inter‐transect areas. Two reconstructions are presented, a wholly empirical version and a version that combines modelling with the new empirical evidence. Palaeoglaciological maps of ice extent, thickness, velocity, and flow geometry at thousand‐year timesteps are presented. The maximum ice volume of 1.8 m sea level equivalent occurred at 23 ka. A larger extent than previously defined is found and widespread advance of ice to the continental shelf break is confirmed during the last glacial. Asynchrony occurred in the timing of maximum extent and onset of retreat, ranging from 30 to 22 ka. The tipping point of deglaciation at 22 ka was triggered by ice stream retreat and saddle collapses. Analysis of retreat rates leads us to accept our hypothesis that the marine‐influenced sectors collapsed rapidly. First order controls on ice‐sheet demise were glacio‐isostatic loading triggering retreat of marine sectors, aided by glaciological instabilities and then climate warming finished off the smaller, terrestrial ice sheet. Overprinted on this signal were second order controls arising from variations in trough topographies and with sector‐scale ice geometric readjustments arising from dispositions in the geography of the landscape. These second order controls produced a stepped deglaciation. The retreat of the British–Irish Ice Sheet is now the world’s most well‐constrained and a valuable data‐rich environment for improving ice‐sheet modelling. Publisher PDF

The Storegga tsunami, dated in Norway to 8150±30 cal. years BP, hit many countries bordering the North Sea. Run‐ups of >30 m occurred and 1000s of kilometres of coast were impacted. Whilst recent modelling successfully generated a tsunami wave train, the wave heights and velocities, it under‐estimated wave run‐ups. Work presented here used luminescence to directly date the Storegga tsunami deposits at the type site of Maryton, Aberdeenshire in Scotland. It also undertook sedimentological characterization to establish provenance, and number and relative power of the tsunami waves. Tsunami model refinement used this to better understand coastal inundation. Luminescence ages successfully date Scottish Storegga tsunami deposits to 8100±250 years. Sedimentology showed that at Montrose, three tsunami waves came from the northeast or east, over‐ran pre‐existing marine sands and weathered igneous bedrock on the coastal plain. Incorporation of an inundation model predicts well a tsunami impacting on the Montrose Basin in terms of replicate direction and sediment size. However, under‐estimation of run‐up persisted requiring further consideration of palaeotopography and palaeo‐near‐shore bathymetry for it to agree with sedimentary evidence. Future model evolution incorporating this will be better able to inform on the hazard risk and potential impacts for future high‐magnitude submarine generated tsunami events. Publisher PDF

This research was funded by the UK Natural Environment Research Council consortium grant NE/J007196/1 BRITICE-CHRONO. The work was supported by the NERC Radiocarbon Facility and NERC Cosmogenic Isotope Facility Analysis. New optically stimulated luminescence dating and Bayesian models integrating all legacy and BRITICE-CHRONO geochronology facilitated exploration of the controls on the deglaciation of two former sectors of the British–Irish Ice Sheet, the Donegal Bay (DBIS) and Malin Sea ice-streams (MSIS). Shelf-edge glaciation occurred ~27 ka, before the global Last Glacial Maximum, and shelf-wide retreat began 26–26.5 ka at a rate of ~18.7–20.7 m a–1. MSIS grounding zone wedges and DBIS recessional moraines show episodic retreat punctuated by prolonged still-stands. By ~23–22 ka the outer shelf (~25 000 km2) was free of grounded ice. After this time, MSIS retreat was faster (~20 m a–1 vs. ~2–6 m a–1 of DBIS). Separation of Irish and Scottish ice sources occurred ~20–19.5 ka, leaving an autonomous Donegal ice dome. Inner Malin shelf deglaciation followed the submarine troughs reaching the Hebridean coast ~19 ka. DBIS retreat formed the extensive complex of moraines in outer Donegal Bay at 20.5–19 ka. DBIS retreated on land by ~17–16 ka. Isolated ice caps in Scotland and Ireland persisted until ~14.5 ka. Early retreat of this marine-terminating margin is best explained by local ice loading increasing water depths and promoting calving ice losses rather than by changes in global temperatures. Topographical controls governed the differences between the ice-stream retreat from mid-shelf to the coast. Publisher PDF

The offshore sector around Shetland remains one of the least well‐studied parts of the former British–Irish Ice Sheet with several long‐standing scientific issues unresolved. These key issues include (i) the dominance of a locally sourced ‘Shetland ice cap’ vs an invasive Fennoscandian Ice Sheet; (ii) the flow configuration and style of glaciation at the Last Glacial Maximum (i.e. terrestrial vs marine glaciation); (iii) the nature of confluence between the British–Irish and Fennoscandian Ice Sheets; (iv) the cause, style and rate of ice sheet separation; and (v) the wider implications of ice sheet uncoupling on the tempo of subsequent deglaciation. As part of the Britice‐Chrono project, we present new geological (seabed cores), geomorphological, marine geophysical and geochronological data from the northernmost sector of the last British–Irish Ice Sheet (north of 59.5°N) to address these questions. The study area covers ca. 95 000 km2, an area approximately the size of Ireland, and includes the islands of Shetland and the surrounding continental shelf, some of the continental slope, and the western margin of the Norwegian Channel. We collect and analyse data from onshore in Shetland and along key transects offshore, to establish the most coherent picture, so far, of former ice‐sheet deglaciation in this important sector. Alongside new seabed mapping and Quaternary sediment analysis, we use a multi‐proxy suite of new isotopic age assessments, including 32 cosmogenic‐nuclide exposure ages from glacially transported boulders and 35 radiocarbon dates from deglacial marine sediments, to develop a synoptic sector‐wide reconstruction combining strong onshore and offshore geological evidence with Bayesian chronosequence modelling. The results show widespread and significant spatial fluctuations in size, shape and flow configuration of an ice sheet/ice cap centred on, or to the east of, the Orkney–Shetland Platform, between ~30 and ~15 ka BP. At its maximum extent ca. 26–25 ka BP, this ice sheet was coalescent with the Fennoscandian Ice Sheet to the east. Between ~25 and 23 ka BP the ice sheet in this sector underwent a significant size reduction from ca. 85 000 to

Predicting the future response of ice sheets to climate warming and rising global sea level is important but difficult. This is especially so when fast‐flowing glaciers or ice streams, buffered by ice shelves, are grounded on beds below sea level. What happens when these ice shelves are removed? And how do the ice stream and the surrounding ice sheet respond to the abruptly altered boundary conditions? To address these questions and others we present new geological, geomorphological, geophysical and geochronological data from the ice‐stream‐dominated NW sector of the last British–Irish Ice Sheet (BIIS). The study area covers around 45 000 km2 of NW Scotland and the surrounding continental shelf. Alongside seabed geomorphological mapping and Quaternary sediment analysis, we use a suite of over 100 new absolute ages (including cosmogenic‐nuclide exposure ages, optically stimulated luminescence ages and radiocarbon dates) collected from onshore and offshore, to build a sector‐wide ice‐sheet reconstruction combining all available evidence with Bayesian chronosequence modelling. Using this information we present a detailed assessment of ice‐sheet advance/retreat history, and the glaciological connections between different areas of the NW BIIS sector, at different times during the last glacial cycle. The results show a highly dynamic, partly marine, partly terrestrial, ice‐sheet sector undergoing large size variations in response to sub‐millennial‐scale climatic (Dansgaard–Oeschger) cycles over the last 45 000 years. Superimposed on these trends we identify internally driven instabilities, operating at higher frequency, conditioned by local topographic factors, tidewater dynamics and glaciological feedbacks during deglaciation. Specifically, our new evidence indicates extensive marine‐terminating ice‐sheet glaciation of the NW BIIS sector during Greenland Stadials 12 to 9 – prior to the main ‘Late Weichselian’ ice‐sheet glaciation. After a period of restricted glaciation, in Greenland Interstadials 8 to 6, we find good evidence for rapid renewed ice‐sheet build‐up in NW Scotland, with the Minch ice‐stream terminus reaching the continental shelf edge in Greenland Stadial 5, perhaps only briefly. Deglaciation of the NW sector took place in numerous stages. Several grounding‐zone wedges and moraines on the mid‐ and inner continental shelf attest to significant stabilizations of the ice‐sheet grounding line, or ice margin, during overall retreat in Greenland Stadials 3 and 2, and to the development of ice shelves. NW Lewis was the first substantial present‐day land area to deglaciate, in the first half of Greenland Stadial 3 at a time of globally reduced sea‐level c. 26 ka bp, followed by Cape Wrath at c. 24 ka bp. The topographic confinement of the Minch straits probably promoted ice‐shelf development in early Greenland Stadial 2, providing the ice stream with additional support and buffering it somewhat from external drivers. However, c. 20–19 ka bp, as the grounding‐line migrated into shoreward deepening water, coinciding with a marked change in marine geology and bed strength, the ice stream became unstable. We find that, once underway, grounding‐line retreat proceeded in an uninterrupted fashion with the rapid loss of fronting ice shelves – first in the west, then the east troughs – before eventual glacier stabilization at fjord mouths in NW Scotland by ~17 ka bp. Around the same time, ~19–17 ka bp, ice‐sheet lobes readvanced into the East Minch – possibly a glaciological response to the marine‐instability‐triggered loss of adjacent ice stream (and/or ice shelf) support in the Minch trough. An independent ice cap on Lewis also experienced margin oscillations during mid‐Greenland Stadial 2, with an ice‐accumulation centre in West Lewis existing into the latter part of Heinrich Stadial 1. Final ice‐sheet deglaciation of NW mainland Scotland was punctuated by at least one other coherent readvance at c. 15.5 ka bp, before significant ice‐mass losses thereafter. At the glacial termination, c. 14.5 ka bp, glaciers fed outwash sediment to now‐abandoned coastal deltas in NW mainland Scotland around the time of global Meltwater Pulse 1A. Overall, this work on the BIIS NW sector reconstructs a highly dynamic ice‐sheet oscillating in extent and volume for much of the last 45 000 years. Periods of expansive ice‐sheet glaciation dominated by ice‐streaming were interspersed with periods of much more restricted ice‐cap or tidewater/fjordic glaciation. Finally, this work indicates that the role of ice streams in ice‐sheet evolution is complex but mechanistically important throughout the lifetime of an ice sheet – with ice streams contributing to the regulation of ice‐sheet health but also to the acceleration of ice‐sheet demise via marine ice‐sheet instabilities.

Comprehensive mapping and the Briticechrono geochronology provides a reconstruction of the last advance and retreat of the only land-terminating ice lobe of the western British Irish Ice Sheet. The Irish Sea Glacier was fed by ice from Lake District, Irish Sea and Wales, and extended to maximum limits in the English Midlands. During ice retreat after 27 kyrs, a series of reverse bedrock slopes rendered proglacial lakes endemic in the land-system. Not resembling the more extensive definitions of the classical ‘Glacial Lake Lapworth’, these ice contact lakes were smaller time transgressive moraine- and bedrock-dammed basins that evolved with ice marginal retreat. Combining, for the first time on glacial sediments, OSL bleaching profiles for cobbles with single grain and small aliquot OSL measurements on sands, has produced a coherent chronology from these heterogeneously bleached samples, and constrained for the Irish Sea Glacier a post 30ka ice maximum advance, 26.5±1.8ka maximum extent, and 25.3±1.6 to 20.6±2.2ka retreat vacating the region. With retreat of the Irish Sea Glacier an opportunistic Welsh re-advance 19.7±2.5ka took advantage of the vacated space and rode over Irish Sea Glacier moraines. Our geomorphological chronosequence shows a glacial system forced by climate, but mediated by piracy of ice sources shared with the larger and marine terminating Irish Sea Ice Stream to the west. The Irish Sea Glacier underwent changes flow regime and fronting environments driven by stagnation and decline as the primary impetus to advance was diverted. Ultimately, the glacier of the English Midlands display complex uncoupling and realignment during deglaciation and ice margin retreat towards upland hinterlands ~17.8 kyrs (Lake District and Pennines) and asynchronous behaviour as individual adjacent ice lobes became increasingly important in driving the landform record.

Accurate Holocene relative sea-level curves are vital for modelling future sea-level changes, particularly in regions where relative sea-level changes are dominated by isostatically induced vertical land movements. In North Wales, various glacial isostatic adjustment (GIA) models predict a mid-Holocene relative sea-level highstand between 4 and 6 ka, which is unsubstantiated by any geological sea-level data but affects the ability of geophysical models to model accurately past and future sea levels. Here, we use a newly developed foraminifera-based sea-level transfer function to produce a 3300-year-long late-Holocene relative sea-level reconstruction from a salt marsh in the Malltraeth estuary on the south Anglesey coast in North Wales. This is the longest continuous late-Holocene relative sea-level reconstruction in Northwest Europe. We combine this record with two new late-Holocene sea-level index points (SLIPs) obtained from a freshwater marsh at Rhoscolyn, Anglesey, and with previously published regional SLIPs, to produce a relative sea-level record for North Wales that spans from ca. 13,000 BP to the present. This record leaves no room for a mid-Holocene relative sea-level highstand in the region. We conclude that GIA models that include a mid-Holocene sea-level highstand for North Wales need revision before they are used in the modelling of past and future relative sea-level changes around the British Isles.

Recent archaeological research in Australia’s north-eastern Kimberley has luminescence dated a large red sedimentary feature, known as Minjiwarra, with artefacts in stratified contexts from the lat...

Mega-blowouts are very large-scale deflationary landforms, formed by wind erosion. They are abundant in the Gonghe basin, northeast margin of the Qinghai-Tibet Plateau (QTP) and little is known about the evolution, dynamics or controls on the mega-blowout development. Here we report on mega-blowouts' morphodynamic expansion rates based on 4 years of monitoring. Also presented is a remotely sensed longer-term (48 years) morphologic change record which is used to understand the initiation, growth and evolution of mega-blowouts in alpine grasslands. Links between the morphodynamics and blowout-controlling factors are analysed. The expansion rates of the monitored blowouts vary according to blowout area, with different parts of the blowouts expanding at different rates. Generally longitudinal (downwind) mega-blowout expansion is greatest, with upwind headwall expansion via collapse being particularly significant. The growth of depositional lobes downwind of mega-blowouts tends to be faster than growth of the deflation basins. Merging of adjacent blowouts is one of the key mechanisms for mega-blowout development and extension. Sediment characteristics, wind erosion, water erosion, and freeze-thaw processes also all play a part in mega-blowout initiation and expansion. However, the relative roles that these factors play may differ according to a blowout's evolutionary stage. Due to an almost unlimited depth of sand, very low water table, and short grass vegetation cover, evolution into parabolic dunes is limited. A large proportion of sand patches and small blowouts around the mega-blowouts are still developing in the Gonghe basin proving that land degradation is still ongoing. Future work will focus on the feedback mechanisms between the blowout morphodynamics, climate change and anthropogenic impacts.

Reported here is the first chronostratigraphic study of the Quaternary fluvial terrace deposits of three different valleys (Deba, Nerbioi, Oiartzun) located in the eastern Cantabrian margin (northern Spain), designed to understand long-term fluvial dynamics of this region. Fourteen samples were collected for numerical dating purpose, in the lowest terrace levels from 5 m to 63 m above current river channel. Optically Stimulated Luminescence dating was performed using the SAR protocol. For samples from terraces >20 m above the current river channel, over 20% of measured aliquots were above saturation of the OSL signal. Consequently, only minimum ages could be estimated. Five samples also underwent Electron Spin Resonance (ESR) dating following the Multiple Centre approach. The ESR signals of the Aluminium and Titanium (Ti-Li and Ti-H) centres were systematically measured in each sample. In particular, the ESR signal of the Ti-H centre was strong enough to derive reliable and meaningful dose estimates. Obtained age results range between ∼140 and ∼400 ka for the terrace levels from +10 to +25 m. They suggest phases of aggradation during MIS 6, MIS 8 and MIS 10, for terrace levels T+10m, T+20m and T+25m, respectively.

(IF 3.82; Q1); International audience; The response by Van Vliet-Lanoë et al. to our paper on potential thermokarst features in Pleistocene alluvial deposits from the Paris Basin (France) presents inconsistencies that we consider here successively. These are (1) the map of the maximum extent of Pleistocene permafrost in France, (2) the genesis of liquefaction and fluidization structures in periglacial environments, (3) the origin of thermokarst lakes and recumbent folds, (4) the depositional context of sandy units, and (5) the age of the studied deposits. All structures result from the interplay between (1) the growth and degradation of ice wedges, which are responsible for the development of a mound-like topography (badland thermokarst reliefs) on the edge of the alluvial terrace and from the initiation of ponding elsewhere on the terrace, (2) the degradation of lithalsa that developed later in the lacustrine deposits. The sequence was dated confidently to the Late Weichselian.

The southern Cape coast of South Africa boasts an impressive suite of Plio-Pleistocene aeolian dune deposits (aeolianite). Previous research has shown that in this region onshore dune accumulation was generally focused around interglacial sea level highstands, with the locus of coastal dune accumulation shifting onto the adjacent continental shelf during glacial sea level lowstands. Here, using new luminescence dating results, we present the first evidence for preserved onshore glacial age dunes. Specifically, on the Robberg Peninsula, a rocky headland 28 km east of Knysna, two phases of aeolianite formation are identified, corresponding to early (45–60 ka) and late (35–30 ka) marine isotope stage (MIS) 3. Subsequently, during the Holocene, all substantive dune accumulation occurred between 10.2 and 7.0 ka, forming cliff-fronting dunes and filling the limited accommodation space on the headland, including an archaeological rock-shelter. Combining these ages with bathymetric data, we infer that this distinct onshore glacial age aeolianite record reflects: 1) restricted accommodation space during sea level highstands; 2) a regional narrowing of the continental shelf, and 3) liberation of sediments lying on a prominent −45 to −60 m offshore terrace, which would have been exposed during MIS 3. This demonstrates that despite broad regional-scale trends in the timing of coastal aeolian activity - driven by commonalities in relative sea level trends and climate - distinct local variations in late Quaternary coastal evolution can be identified. This is ascribed to local controls on preservation (accommodation space) and sediment supply (shoreline position and antecedent offshore sediment supplies). Such findings may have wider implications for interpretations of site context/resource availability at several notable coastal archaeological sites, and more broadly suggest that local offshore or onshore geologic contexts can at times assume greater influence on a preserved coastal aeolianite record than the regional-scale trends in sea level and climate.

The 2.056 Ma Bushveld Complex (BC) constitutes the largest layered igneous complex known. The complex forms a basin defined by strata that dip centripetally (10° to 20°). This depression presumably resulted from the load of the complex as was proposed by a number of authors. Sagging of between 460 to 740 m appears possible, resulting in flexural-slip movement. This flexural-slip manifests in many thrust faults, (mainly mapped in mines) which display reverse-slip. The research described in this paper focuses on the age of this deformation. A thrust fault was identified at Lonmin U14 Pit. Reverse slip along the fault displaced unconsolidated sedimentary material that unconformably overlies the Rustenburg Layered Suite strata. Archaeological artefacts (Acheulian hand axes) were discovered buried in this sedimentological layer and provide an age constraint of 1.25 Ma to 250 000 years. Optically stimulated luminescence (OSL) dating further constrained the age of the sedimentary material to less than 175 000 years. The youngest material deposited is a regional black clay layer. At Lonmin U14 Pit this clay layer carries a fabric that resulted from the movement of the thrust and this indicates an age significantly younger than 175 000 years.

This research investigates the landscape instability associated with the drift sands, which are widespread across north-western Europe. It focuses on Breckland, UK using new sites along with existing geomorphic, archaeological and historical data. This shows landscape instability of drift sands occurred at 5240 ± 1040 years BCE, 600 ± 100, 1150 ± 50, 1600 and ~1790 CE. Comparison of these phases to climate records show no clear patterns with drifting occurring during dry/wet as well as cold/warm periods. Additionally, similar climatic shifts lead to diverging reactions of landscapes in different regions throughout Europe. At the regional scale, land usage and population pressures also may not be the direct cause of sand drifting, suggesting that complex responses or different triggers at different times were responsible. Within this, society's unawareness of the inherent landscape instability and the threat posed by the sand hazard may have been important as it affected whether mitigation measures were or could be implemented. In Breckland, initial instability may have been due to the establishment of the open field system on virgin soil. Later changes in land ownership and associated power within the society, led to an inability of communities to implement mitigation measures and large land owners abstaining from tackling the sand hazard. Whilst the widespread coversands and climatic extremes provide the underlying susceptibility to sand drifting, it would appear that drift sands of the last 2000 years may provide less of a sedimentary archive of Late Holocene climatic changes and more a record of land management changes. ispartof: GEOMORPHOLOGY vol:323 issue:15 december 2018 pages:123-134 status: Published online

Whilst the Late Devensian glaciation (MIS2) of the Vale of Pickering is well-documented, earlier glaciations within it are not. A proposed limited glaciation in the Mid-Pleistocene, thought to be of Marine Isotope Stage 8 (MIS) age is not well constrained. This paper aims to obtain preliminary ages for two of the most prominent geomorphic features in the Vale of Pickering to see if they related to pre-Devensian glaciations. New luminescence dating by infra-red stimulation of feldspars from sand accumulations near the summit of Gallows Hill, part of the Wykeham Moraine, and from a section through poorly sorted fluvial sand and gravel on the flanks of the Hutton Buscel Terrace in Yedman Dale gave ages of 176 ± 14 ka and 156 ± 12 ka, respectively. Evidence suggests they represent a glacial incursion (MIS 6) into the Vale of Pickering blocking its eastern end and forming a pre-Devensian Glacial Lake Pickering. Whilst they could be older, this style of glaciation is very different to the limited plateau ice-field proposed for MIS 8 at the western end of the Vale of Pickering. Taken at face value, these preliminary ages suggest that the Vale of Pickering was partially glaciated in MIS 6 as part of a wider ice sheet and contemporary with the Saalian glaciation in Europe.

The African Middle Stone Age (MSA, typically considered to span ca. 300–30 thousand years ago [ka]), represents our species’ first and longest lasting cultural phase. Although the MSA to Later Stone Age (LSA) transition is known to have had a degree of spatial and temporal variability, recent studies have implied that in some regions, the MSA persisted well beyond 30 ka. Here we report two new sites in Senegal that date the end of the MSA to around 11 ka, the youngest yet documented MSA in Africa. This shows that this cultural phase persisted into the Holocene. These results highlight significant spatial and temporal cultural variability in the African Late Pleistocene, consistent with genomic and palaeoanthropological hypotheses that significant, long-standing inter-group cultural differences shaped the later stages of human evolution in Africa. Introduction Results Discussion Materials and methods - Fieldwork - OSL dating methodology - Lithic analysis

International audience; The BRITICE-CHRONO Project has generated a suite of recently published radiocarbon ages from deglacial sequences offshore in the Celtic and Irish seas and terrestrial cosmogenic nuclide and optically stimulated luminescence ages from adjacent onshore sites. All published data are integrated here with new geochronological data from Wales in a revised Bayesian analysis that enables reconstruction of ice retreat dynamics across the basin. Patterns and changes in the pace of deglaciation are conditioned more by topographic constraints and internal ice dynamics than by external controls. The data indicate a major but rapid and very short-lived extensive thin ice advance of the Irish Sea Ice Stream (ISIS) more than 300 km south of St George's Channel to a marine calving margin at the shelf break at 25.5 ka; this may have been preceded by extensive ice accumulation plugging the constriction of St George's Channel. The release event between 25 and 26 ka is interpreted to have stimulated fast ice streaming and diverted ice to the west in the northern Irish Sea into the main axis of the marine ISIS away from terrestrial ice terminating in the English Midlands, a process initiating ice stagnation and the formation of an extensive dead ice landscape in the Midlands.

Previous investigation of isolated landforms, on the eastern margin of the East Anglian Fenland, England, has demonstrated that they represent an ice-marginal delta and alluvial fan complex deposited at the margin of an ice lobe that entered the Fenland during the ‘Tottenhill glaciation’ (termed the ‘Skertchly Line’). They have been attributed, based on regional correlations, to a glaciation during the Late Wolstonian (i.e. Late Saalian) Substage (Drenthe Stadial, early Marine Isotope Stage (MIS) 6). This paper aimed to test this correlation by directly optically luminescence dating, for the first time, sediments found within the Skertchly Line at Shouldham Thorpe, Norfolk, and Maidscross Hill, Suffolk, together with those in associated kame terrace deposits at Watlington, Norfolk. Ages ranged from 244 ± 10 ka to 12.8 ± 0.46 ka, all the results being younger than MIS 8 with some clearly showing the landforms have been subsequently subjected to periglacial processes, particularly during the Late Devensian Substage (∼MIS 2). Most of the remainder fall within the range 169–212 ka and could be assigned to MIS 6, thus confirming the previously proposed age of the glaciation. The local and regional implications of these conclusions are discussed, the maximum ice limit being linked to that of the Amersfoort–Nijmegen glaciotectonic ridge limit in the central Netherlands.

Since the 1990s the Mekong River delta has suffered a large decline in sediment supply causing coastal erosion, following catchment disturbance through hydropower dam construction and sand extraction. However, our new geological reconstruction of 2500-years of delta shoreline changes show that serious coastal erosion actually started much earlier. Data shows the sandy coast bounding river mouths accreted consistently at a rate of +2 to +4 km2/year. In contrast, we identified a variable accretion rate of the muddy deltaic protrusion at Camau; it was 2/year before 1400 years ago but increased drastically around 600 years ago, forming the entire Camau Peninsula. This high level of mud supply had sharply declined by the early 20th century after a vast canal network was built on the delta. Since then the Peninsula has been eroding, promoted by the conjunction of mud sequestration in the delta plain driven by expansion of rice cultivation, and hysteresis of long-term muddy sedimentation that left the protrusion exposed to wave erosion. Natural mitigation would require substantial increases in sediment supply well above the pre-1990s levels.

The influence of the direct application of power ultrasound (PUS) at several frequencies and power densities to Portland cement (PC) pastes is investigated in detail. Two PC pastes at water-to-cement ratios of 0.50 and 0.80 were studied. The composition of the pore solution and hydrates after introducing PUS irradiation for various periods were examined using ICP-OES, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) techniques. The results indicate for the first time that applied PUS used in this study, can disturb the early formation of ettringite whilst appreciably promoting the formation of amorphous aluminium hydroxide hydrate by considerably releasing the aluminium ions into the pore solution. Moreover, PUS can increase carbonates by intensifying the carbonation in the PC systems particularly the system with higher water content. The present research concludes that ultrasound could be a promising technique to enhance ternesite hydration in ternesite-rich belitic calcium sulphoaluminate cements.

Blowouts are wind‐eroded landforms that are widely distributed in the north‐eastern part in Qinghai–Tibet Plateau (QTP), China. These blowouts are thought to form in response to climate change and/or human activity but little is known about their morphodynamics. Using field surveys, remote sensing and geographic information system (GIS) spatial analysis, the distribution and morphology of blowouts are analysed and their initiation considered. Results show the QTP mega‐blowouts are some of the largest in the world. The orientations of the trough shaped blowouts are parallel with the prevailing wind, but the saucer and bowl‐shaped blowouts are influenced by bi‐directional transport. Whilst regional patterns of blowout shape and size were observed to reflect the extent of aeolian sediments and wind regimes, the relationship between the different morphological parameters showed consistency. During initial stages of development, the length to width ratios of blowouts increase rapidly with area but after they reach a mega size this relationship stabilizes as blowouts widen. Initial luminescence dating shows that blowouts appear to have initiated ~100 to 500 years ago, coinciding with the Little Ice Age (LIA) climate event when northwest winds are known to have intensified. Further work is required to confirm this initiation period and establish the significance of mega blowouts for landscape degradation and human activities.

Understanding the geomorphology left by waxing and waning of former glaciers and ice sheets during the late Quaternary has been the focus of much research. This has been hampered by the difficulty in dating such features. Luminescence has the potential to be applied to glacial sediments but requires signal resetting prior to burial in order to provide accurate ages. This paper explores the possibility that, rather than relying on light to reset the luminescence signal, glacial processes underneath ice might cause resetting. Experiments were conducted on a ring-shear machine set up to replicate subglacial conditions and simulate the shearing that can occur within subglacial sediments. Luminescence measurement at the single grain level indicates that a number (albeit small) of zero-dosed grains were produced and that these increased in abundance with distance travelled within the shearing zone. Observed changes in grain shape characteristics with increasing shear distance indicate the presence of localised high pressure grain-to-grain stresses caused by grain bridges. This appears to explain why some grains became zeroed whilst others retained their palaeodose. Based on the observed experimental trend, it is thought that localised grain stress is a viable luminescence resetting mechanism. As such relatively short shearing distances might be sufficient to reset a small proportion of the luminescence signal within subglacial sediments. Dating of previously avoided subglacial sediments may therefore be possible.

Analyses of aeolianites and associated dune, surficial carbonate and marine terrace sediments from north-central Chile (27° 54′ S) yield a record of environmental change for the coastal southern Atacama Desert spanning at least the last glacial-interglacial cycle. Optically stimulated luminescence dating indicates phases of aeolian dune construction at around 130, 111–98, 77–69 and 41–28 ka. Thin-section and stable carbon and oxygen isotope analyses suggest a predominantly marine sediment source for the three oldest dune phases. Aeolianites appear to have accumulated mainly from tectonically-uplifted interglacial marine sediments that were deflated during windier and/or stormier intervals. Bedding orientations indicate that sand-transporting winds varied in direction from S-ESE during MIS 5e and WNW-ESE during MIS 5c-5a. Winds from the southeast quadrant are unusual today in this region of the Atacama, suggesting either major shifts in atmospheric circulation or topographic airflow modification. Thin-section evidence indicates that the aeolianites were cemented by two phases of vadose carbonate, tentatively linked to wetter periods around 70 and 45 ka. Tectonic uplift in the area has proceeded at an average rate of 305–542 mm kyr− 1. The study illustrates the complexity of understanding onshore-offshore sediment fluxes in the context of Late Quaternary sea-level fluctuations for an area undergoing rapid tectonic uplift.

The eastern England terrestrial glacial sequences are critical to the spatial and temporal reconstruction of the last British−Irish Ice sheet (BIIS). Understanding glacial behaviour in the area of the Humber Gap is key as its blockage by ice created extensive proglacial lakes. This paper maps the glacial geomorphology of the Humber Gap region to establish for the first time the extent and thickness of the North Sea Lobe (NSL) of the BIIS. Findings establish the westerly maximal limit of the NSL. Ten new luminescence ages from across the region show the initial Skipsea Till advance to the maximal limits occurred regionally at c. 21.6 ka (Stage 1) and retreated off-shore c. 18 ka (Stage 2). Punctuated retreat is evident in the south of the region whilst to the immediate north retreat was initially rapid before a series of near synchronous ice advances (including the Withernsea Till advance) occurred at c. 16.8 ka (Stage 3). Full withdrawal of BIIS ice occurred prior to c. 15 ka (Stage 4). Geomorphic mapping and stratigraphy confirms the existence of a proto Lake Humber prior to Stage 1, which persisted to Stage 3 expanding eastward as the NSL ice retreated. It appears that proglacial lakes formed wherever the NSL encountered low topography and reverse gradients during both phases of both advance and retreat. These lakes may in part help explain the dynamism of parts of the NSL, as they initiated ice draw down and associated streaming/surging. The above record of ice-dammed lakes provides an analogue for now off-shore parts of the BIIS where it advanced as a number of asynchronous lowland lobes.

The Kidluit Formation (Fm) is a fluvial sand deposit that extends regionally across the Tuktoyaktuk Coastlands, western Arctic Canada. It was deposited by a large river flowing north into the Arctic Ocean prior to development of a cold-climate sandy desert and later glaciation by the Laurentide Ice Sheet. Lithostratigraphic and sedimentological field observations of the Summer Island area indicate deposition of the Kidluit Fm by a braided river system. Optical stimulated luminescence (OSL) dating of Kidluit sand provides eight OSL ages of 76–27 ka, which indicate deposition during Marine Isotope Stage (MIS) 4 and MIS 3. Radiocarbon dating of well-preserved weevil remains, a willow twig, wild raspberry seeds and bulrush achenes provides non-finite 14C ages of >52,200, >51,700, >45,900 and >54,700 14C BP and are assigned an age of either MIS 4 or early MIS 3. Plant macrofossils from the sand deposit indicate spruce forest conditions and climate slightly warmer than present, whereas insect fossils indicate tundra conditions slightly colder than present. The river system that deposited the Kidluit Fm was probably either a pre-Laurentide Mackenzie River or the palaeo-Porcupine River, or a combination of them.

© 2018 The Geologists' Association During the last (MIS 2) and older glaciations of the North Sea, a North Sea Lobe (NSL) of the British-Irish Ice Sheet flowed onshore and terminated on the lowlands of eastern England, constructing inset sequences of either substantial ice-marginal deposits and tills or only a thin till veneer, indicative of complex and highly dynamic glaciological behaviour. The glaciation limit represented by the Marsh Tills and the Stickney and Horkstow Moraines in Lincolnshire is regarded as the maximum margin of the NSL during MIS 2 and was attained at ∼19.5 ka as determined by OSL dating of overridden lake sediments at Welton le Wold. A later ice marginal position is recorded by the Hogsthorpe-Killingholme Moraine belt, within which ice-walled lake plains indicate large scale ice stagnation rapidly followed ice advance at ∼18.4 ka based on dates from supraglacial lake deposits. The NSL advanced onshore in North Norfolk slightly earlier constructing a moraine ridge at Garrett Hill at ∼21.5ka. In addition to the large ice-dammed lakes in the Humber and Wash lowlands, we propose that an extensive Glacial Lake Lymn was dammed in the southern Lincolnshire Wolds by the NSL ice margin at the Stickney Moraine. Previous proposals that older glacier limits might be recorded in the region, lying between MIS 2 and MIS 12 deposits, are verified by our OSL dates on the Stiffkey moraine, which lies immediately outside the Garrett Hill moraine and appears to be of MIS 6 age.

While there is extensive evidence for the Late Devensian, less is known about Early and Middle Devensian (approx. 110–30 ka) climates and environments in the UK. The Greenland ice-core record suggests the UK should have endured multiple changes, but the terrestrial palaeo-record lacks sufficient detail for confirmation from sites in the British Isles. Data from deposits at Finningley, South Yorkshire, can help redress this. A channel with organic silts, dated 40 314–39 552 cal a BP, contained plant macrofossil and insect remains showing tundra with dwarf-shrub heath and bare ground. Soil moisture conditions varied from free draining to riparian, with ponds and wetter vegetated areas. The climate was probably low arctic with snow cover during the winter. Mutual climatic range (MCR), based on Coleoptera, shows the mean monthly winter temperatures of −22 to −2°C and summer ones of 8–14°C. Periglacial structures within the basal gravel deposits and beyond the glacial limits indicate cold-climate conditions, including permafrost. A compilation of MCR reconstructions for other Middle Devensian English sites shows that marine isotope stage 3—between 59 and 28 ka—experienced substantial variation in climate consistent with the Greenland ice-core record. The exact correlation is hampered by temporal resolution, but the Finningley site stadial at approximately 40 ka may correlate with the one of the Greenland stadials 7–11.

© 2018 John Wiley & Sons, Ltd. During the last glacial cycle an intriguing feature of the British-Irish Ice Sheet was the North Sea Lobe (NSL); fed from the Firth of Forth and which flowed south and parallel to the English east coast. The controls on the formation and behaviour of the NSL have long been debated, but in the southern North Sea recent work suggests the NSL formed a dynamic, oscillating terrestrial margin operating over a deforming bed. Further north, however, little is known of the behaviour of the NSL or under what conditions it operated. This paper analyses new acoustic, sedimentary and geomorphic data in order to evaluate the glacial landsystem imprint and deglacial history of the NSL offshore from NE England. Subglacial tills (AF2/3) form a discontinuous mosaic interspersed with bedrock outcrops across the seafloor, with the partial excavation and advection of subglacial sediment during both advance and retreat producing mega-scale glacial lineations and grounding zone wedges. The resultant ‘mixed-bed’ glacial landsystem is the product of a dynamic switch from a terrestrial piedmont-lobe margin with a net surplus of sediment to a partially erosive, quasi-stable, marine-terminating, ice stream lobe as the NSL withdrew northwards. Glaciomarine sediments (AF4) drape the underlying subglacial mixed-bed imprint and point to a switch to tidewater conditions between 19.9 and 16.5 ka cal BP as the North Sea became inundated. The dominant controls on NSL recession during this period were changing ice flux through the Firth of Forth ice stream onset zone and water depths at the grounding line; the development of the mixed-bed landsystem being a response to grounding line instability. © 2018 John Wiley & Sons, Ltd.

Presented here is a new bench-top research device for the measurement of the optical turbidity of natural sediment-laden water samples. This prototype device employs 18 unique angular measurement positions and a variety of user-selectable LED light sources. The motivation for this project was the need to generate more parameter-rich data sets pertaining to the light-scattering properties of natural sediment suspensions, and to address the issues raised by Kitchener et al. (2017) concerning the inconsistent calibration methodologies currently employed to quantify suspended sediment concentration (SSC) by optical turbidity measurement. The mechanical design comprises re-purposed waste plastic materials and 3D-printed parts. The active light-source control and monitoring hardware and firmware executes on the open-source Arduino embedded microcontroller platform. The modular light sensors plug into any of the angular measurement positions, providing a 0–5 V nominal output signal, which is readable by the user’s choice of data-acquisition system. The device will facilitate the highly detailed characterization of suspended sediment samples, providing 18 voltage output channels for analysis by the user. The precise calibration of the light sensors is by the use of neutral density (ND) filters in conjunction with light-source electrical current measurements, providing light-source intensity values as required. The empirical data provided by existing turbidity meters are acquired using incommensurate methodologies, and therefore they are not cross-comparable. A new methodology, described here, facilitates the cross-comparability of turbidity measurements. Keywords: Turbidity, Suspended-sediment, Sensors, Arduino, Light-absorption, Light-scattering, Open-source hardware

To address long-standing questions concerning Southern Hemisphere climate dynamics and palaeoecological change in southern Africa, a Late Glacial-Holocene alluvial sediment sequence from the relatively dry interior year-round rainfall zone in South Africa was investigated. The study site borders the Fynbos biome and Succulent Karoo biome ecotone, and comprises a rare stratified sequence of sandy and organic-rich silt deposits, shown to span the last 14,000 years. A high resolution multi-proxy record of ecological change was derived using pollen, phytoliths and organic geochemical analyses. For the period 14–11 ka, significant valley aggradation occurred under relatively drier conditions, followed, during the early and middle Holocene, by alternating phases of humid and dry events with higher stream energy, slower accumulation or subtle seasonality changes. A transition from relatively humid to more arid conditions at 4–3 ka is identified and is consistent in timing with several interior year-round rainfall zone records. Results revealed alternations of fynbos and karroid elements and C3/C4 grasses throughout the last fourteen thousand years, but did not suggest large-scale biome shifts. The record joins a growing number of sites contributing to debate over the complex atmospheric-oceanic drivers of palaeoclimate in this region. These data broadly fit to the regional pattern for the southernmost interior of South Africa in showing alternating influences from the westerly winter rain systems in the early Holocene, with a greater contribution from subtropical summer rain system during the middle and later Holocene.

Chronometrically dated Pleistocene records of human occupations of West Africa are rare but offer critical information with which to explore patterns of human origins and adaptation both within the region and more widely across the continent. A number of Middle Stone Age sites are known from the larger river valleys of West Africa, but recent work at the site of Tiemassas has highlighted the presence of Late Pleistocene occupations of the West African coastline. Tiemassas is the westernmost Middle Stone Age site known from Africa, and is located at the interface of Sudanian savannahs, Guinean forest-savannah mosaics and mangrove habitats. Research in the 20th century identified rich collections of MSA stone tools at the site, and our earlier excavations at Tiemassas have constrained an occupation to ca. 44 thousand years ago. Here, we present the results of further chronological dating and detailed analyses of lithic assemblages from new excavations at the site. We synthesize these new findings with the wider suite of evidence from the site to characterize MSA occupations of the West African coast to between 62 and 25 thousand years ago. Our results suggest considerable technological continuity in stone tool technologies at Tiemassas. Despite the immediate proximity of the coastline, there is little evidence at present to suggest direct engagement with coastal resources by MSA populations. Rather, the ecotonal position of the site, alongside more diffuse benefits of its coastal position, may have provided an attractive context for Middle Stone Age occupation.

Having developed in the later Quaternary Period, the Mui Ne dunefield, representing the upper-most portion of a major coastal barrier complex in SE Vietnam, formed by wind regimes associated with the Asian monsoon climate. The barrier complex is 100 km long and higher than 150 m in elevation but despite its large dimensions, research on its geomorphological and geological characterization is limited. Several active dune fields extend 2–10 km landwards from the coast while the rest of the barrier surface is stabilized. We applied ground-penetrating radar (GPR) and quartz optically-stimulated luminescence (OSL) dating to the transverse dunes of the Mui Ne dunefield to characterize the morphostratigraphy and recent aeolian sedimentation history. Currently the dunes have a relief of typically 5–10 m and a wavelength of 50–100 m. They are driven by the northeasterly winter monsoon winds and reversed with minor relief in response to the southwesterly summer monsoon. GPR profiles and OSL ages define three morphostratigraphic units: the modern, Holocene, and Pleistocene dune units. The GPR data of the modern dune unit is dominated by a series of steep reflections that dip exclusively towards the west reflecting the winter monsoon and is punctuated by reactivation surfaces. Evidence for the wind reversal is not preserved in the sediment successions but is represented by reactivation surfaces. Thus a subunit bounded by the reactivation surfaces defines annual deposition. The preservation potential of a subunit varies with the migration rate of the transverse dune, and in the fastest migrating dunes, approximately one subunit was preserved every year (1.1 ± 0.6 subunit/yr). The modern dunes are generally younger than 100 years and have migrated WSW at net rates of 0.6–2.5 m/yr. The Holocene dune unit is as thick as the modern unit although it spans a period, ten times longer, reflecting the lower preservation potential of the transverse dunes as sedimentary records, due to erosion associated with their migration. The rate of dune migration suggests that an aeolian contribution of coastal sands has occurred following the sea level highstand of the Middle Holocene, accounting for the extent of the active dunefields. This mode of the barrier accumulation is considered as an analogue for earlier highstand events. However, the dunefields only cover a fraction of the entire barrier. It is thus inferred that barrier formation occurred over a long period, probably encompassing several glacial-interglacial cycles. Sand accumulation during the lowstand, either by transport of sand from the subaerially exposed shelf and/or reworking of sand emplaced during the prior highstand, may contribute significantly to the barrier development.

Many dune fields that have formed along the southern coast of the Japan Sea are influenced by the north-westerly winter monsoon, which transports beach sand landwards. The Tottori coastal dune field of the Japan Sea has not been disturbed much by human activities until the 20th century and thus is expected to provide a continuous record of the relationships between the winter monsoon and aeolian sedimentation. We examined new ground-penetrating radar profiles and optically stimulated luminescence (OSL) ages of quartz sand from transverse dune ridges in the western part of the dune field in addition to existing data in the eastern part. This allowed us to extend the study period to cover the past 1000 years and to effectively compare the sedimentary record with other coastal dune fields in East Asia and other palaeoenvironmental proxies. OSL ages from older dune sediments suggest considerable aeolian activity from the 10th to 12th century AD, whereas a hiatus of dune sediment record between the 12th and 15th centuries was detected. These results suggest that during the Medieval period aeolian activity was low or that extensive erosion removed most of the deposits. Since the late 15th century, dune sedimentation has apparently been broadly continuous, though with periods of higher and lower activity. In both of the eastern and western parts, most of the dune ridges accreted landwards, but clear seaward accretion occurred during the 18th century, possibly reflecting a decrease in wind strength that restricted sand transport. In contrast, two significant landward accretion events are inferred to have occurred from the late 15th to 17th centuries and around 1840, corresponding to periods of increased dust fall in China, which suggests an enhanced winter monsoon, and to cold periods suggested by the decline of the sunspot number. The timing of periods of inactive and active dune sedimentation, inferred from alternations of organic soil and aeolian sand, in other coastal dune fields of East Asia appears to be concordant with corresponding periods in the Tottori dune field. We thus propose that other Japan Sea dune fields may also provide a valuable record of East Asian winter monsoon fluctuations.

During the Last Glacial Maximum, the Vale of York and North Sea lobes of the British and Irish Ice Sheet extended to within 10 km of each other, impounding a series of pro-glacial lakes. Such an interplay of ice lobes provides a useful analogue for elsewhere in the North Sea basin. This paper focusses on reconstructing the Vale of York and North Sea Ice lobes using a regional suite of 25 luminescence ages in combination with stratigraphical and geomorphic evidence. Results extend and revise the chronology of the Dimlington LGM typesite, showing that the North Sea Ice lobe advanced between 20.9–17.1 ka and 17.1–15.1 ka before present. Initially this lobe impounded a proto Lake Humber which likely covered parts of Holderness as well as the southern part of the Vale of York. Later stages of Lake Humber within the Vale of York show continued blockage of the Humber Gap by the North Sea Ice lobe. The Vale of York Ice extended briefly at ∼18.7 ± 0.63 ka across Lake Humber into South Yorkshire and North Lincolnshire before retreating to and forming the Escrick and York moraines. Both glacier lobes appear to have been short-lived, comprising relatively dynamic ice, especially when moving into areas of deformable lacustrine sediments, which allowed them to rapidly advance and over-extend their margins due to low basal shear stress. Topographic control of the extent and spatial positioning of both Ice lobes also appears to have been significant.

Oriented lakes—characterized by elongate forms, central basins and shallow littoral shelves—are common features of circum-arctic coastal lowlands. The environmental conditions, geological processes and chronology associated with the development of oriented lakes, however, are little known but essential for understanding how such Arctic lowlands evolve. Using combined techniques of field and drill-log stratigraphy and sedimentology, luminescence and radiocarbon dating methods and geomorphic mapping, we reconstruct the landscape evolution leading toward oriented-lake formation on the McKinley Bay Coastal Plain of western Arctic, Canada—a region with over 900 oriented lakes. Most lakes with deep central basins are inherited from a preglacial braidplain (ca. 73–27 ka) and alluvial braided-channel network that extended beyond the glacial limit (ca. 18.6–14.3 ka). Eolian erosion, active during the lateglacial and postglacial period (ca. 12.8–1.9 ka), reworked fluvial deposits. Eolian processes modified existing basins and created other shallow deflationary basins, as small barchanoid dunes migrated under cold, dry paraglacial conditions between about 12.8 and 10.7 ka. Vegetation cover developed at the onset of the early Holocene climatic optimum ca. 10.7 ka, and parabolic dunes were active between 9.6 and 4.6 ka. Thus, oriented lakes developed in basins conditioned by fluvial and eolian processes. In the absence of much near-surface ground ice, lateral expansion of deep-basin lakes and shallow stabilized deflationary basins predominated during the late Holocene through wind-induced wave and current processes. Overall, this sequence of oriented-lake formation does not support a thaw-lake cycle but, rather, small-basin evolution of a periglacial landscape.

Archaeological surveys and excavations in the Jebel Oraf palaeolake basin, north-western Saudi Arabia, have identified a well-preserved early- to mid-Holocene landscape. Two types of occupation site can be distinguished: nine small and ephemeral scatters from single occupation phases on the slopes of sand dunes and three hearth sites indicative of repeated occupation on palaeolake shorelines. In addition, 245 rock art panels, 81 cairns, and 15 stone structures were recorded. This diverse dataset provides an opportunity to reconstruct occupation patterns and changes in landscape use. A particularly important site, Jebel Oraf 2, documents two episodes of lake high stands at ca. 6500 BC and 5300 BC, flooding parts of the locality. Neolithic pastoralists likely occupied the site after the end of the wet season, when the terrain was dry. Earlier sites are located in dune embayments some 7–14 m above the shore of the palaeolake. These locations are consistent with hunting strategies identifiable in the rock art that suggest wildlife was ambushed at watering places. Later rock art at Jebel Oraf also documents the hunting of wild camel in the Iron Age. The lithic industries documented in the Jebel Oraf basin support arguments of repeated contact with Levantine populations.

The expression of storm events in the geological record is poorly understood; therefore, stratigraphic investigations of known events are needed. The 1953 North Sea storm surge was the largest natural disaster for countries bordering the southern North Sea during the twentieth century. We characterize the spatial distribution of a sand deposit from the 1953 storm surge in a salt marsh at Holkham, Norfolk (UK). Radionuclide measurements, core scanning X-ray fluorescence (Itrax), and particle size analyses, were used to date and characterise the deposit. The deposit occurs at the onset of detectable 137Cs - coeval with the first testing of nuclear weapons in the early 1950s. The sand layer is derived from material eroded from beach and dunes on the seaward side of the salt marsh. After the depositional event, accumulation of finer-grained silt and clay materials resumed. This work has important implications for understanding the responses of salt marshes to powerful storms and provides a near-modern analogue of storm surge events for calibration of extreme wave events in the geological record.

(IF 3.68; Q1); International audience; Last Glacial fluvial sequences in the Paris Basin show laminated lacustrine deposits OSL and radiocarbon dated to between 24.6 and 16.6 ka in one site and overlying alluvial sandy gravel. A thermokarst origin of the lakes is supported by abundant traces of ground ice, particularly ice wedge pseudomorphs beneath the lacustrine layers and synsedimentary deformation caused by thaw settlement. The features include brittle deformation (normal and reverse faults) resulting from ground subsidence owing to ice melting and ductile deformations caused by slumping of the sediments heaved by the growth of ice-cored mounds. These correspond to lithalsas (or lithalsa plateaus) and/or to open system pingos. At least two generations of thermokarst are recorded and may reflect the millennial climate variability typical of the Last Glacial. The structures studied in quarries are associated with an undulating topography visible in 5-m DEMs and a spotted pattern in aerial photographs. The search for similar patterns in the Paris Basin indicates that many other potential thermokarst sites exist in the Last Glacial terrace (Fy) of rivers located north of 48°N when they cross the lower Cretaceous sands and marls. In some sites, the presence of organic-poor, fine-grained deposits presumably of lacustrine origin was confirmed by borehole data. The site distribution coincides broadly with that already known for ice wedge pseudomorphs. This study provides new evidence of permafrost-induced ground deformations in France and strongly suggests that thermokarst played a significant and probably largely underestimated role in the genesis of Late Pleistocene landscapes.

International audience; Much of France remained unglaciated during the Late Quaternary and was subjected to repeated phases of periglacial activity. Numerous periglacial features have been reported but disentangling the environmental and climatic conditions they formed under, the timing and extent of permafrost and the role of seasonal frost has remained elusive. The primary sandy infillings of relict sand-wedges and composite-wedge pseudomorphs record periglacial activity. As they contain well-bleached quartz-rich aeolian material they are suitable for optically stimulated luminescence dating (OSL). This study aims to reconstruct when wedge activity took place in two regions of France; Northern Aquitaine and in the Loire valley. Results from single-grain OSL measurements identify multiple phases of activity within sand wedges which suggest that wedge activity in France occurred at least 11 times over the last 100 ka. The most widespread events of thermal contraction cracking occurred between ca. 30 and 24 ka (Last Permafrost Maximum) which are concomitant with periods of high sand availability (MIS 2). Although most phases of sand-wedge growth correlate well with known Pleistocene cold periods, the identification of wedge activity during late MIS 5 and the Younger Dryas strongly suggests that these features do not only indicate permafrost but also deep seasonal ground freezing in the context of low winter insolation. These data also suggest that the overall young ages yielded by North-European sand-wedges likely result from poor record of periglacial periods concomitant with low sand availability and/or age averaging inherent with standard luminescence methods.