Late Devensian Research Articles

The Late‐Devensian proglacial Lake Humber: new evidence from littoral deposits at Ferrybridge, Yorkshire, England

Proglacial Lake Humber is of UK national significance in terms of landscape drainage and development of the British Ice Sheet (BIS) during Marine Isotope Stage 2 (MIS 2), yet it is poorly understood in terms of its dynamics and timing. Sands and gravels exposed at Ferrybridge, West Yorkshire, UK, are interpreted as part of the Upper Littoral sands and gravels related to a high‐level Lake Humber, which inundated the Humber Basin to ∼30 m OD during MIS 2. Excavations exposed well‐rounded gravels of local origin extending downslope from the 27.5 m OD contour and interbedded sands and fine gravels, which are interpreted as the coarse littoral deposits and nearshore associated deposits. A sample from the distal sands returned an Optically Stimulated Luminescence age of 16.6±1.2 kyr, providing the first direct age for the high‐level lake and for when North Sea Basin ice must have blocked the Humber Gap. An underlying sequence included a diamicton dated to after 23.3 ±1.5 kyr and before 20.5±1.2 kyr, indicating that the Late Devensian ice reached at least 15 km south of the Escrick Moraine prior to the high‐level lake. Previous to both the high‐level lake and this ice advance, loess found at the two sites investigated indicates a long period of loess deposition earlier in MIS 2. These new data for the history of Lake Humber are discussed in the context of ice‐marginal oscillations in both the Vale of York and the North Sea Basin.

The Last Glacial Maximum British–Irish Ice Sheet: a reconstruction using digital terrain mapping

AbstractThe use of digital terrain mapping in determining the anatomy of the Late Devensian British–Irish Ice Sheet at a resolution of 500 m cell size is illustrated for Boulton et al.'s 1985 and 1991 models and Lambeck's 1995 model of the ice sheet at its maximum extent as an independent ice mass. Area and volume of the ice sheet are given for each model and the spatial pattern of ice thickness shown in maps. The analyses show that if no account is taken of topography beneath the ice surface, models will seriously overestimate ice volume. It is suggested that as reconstructions of the ice sheet improve, detailed models of ice thickness at the resolution given in this paper may be of value in determining the contribution of the ice sheet to sea surface changes as well as in determining the effects of ice loading on glacio‐isostasy, neotectonics and possibly on paraglacial processes in areas of high relief. Copyright © 2007 John Wiley & Sons, Ltd.

Structural and depositional evidence for repeated ice-marginal oscillation along the eastern margin of the Late Devensian Irish Sea Ice Stream

Late Devensian glacigenic sediments and landforms along the north-west coast of Wales document the advance and subsequent retreat of the eastern margin of an Irish Sea Ice Stream that met, coalesced and ultimately uncoupled from ice radiating outwards from the adjacent Welsh Ice Cap centred over Snowdonia. Across the boundary between the two former ice masses is a set of sediment–landform assemblages that reflect rapidly changing erosional and depositional conditions during ice interaction. From the inner part of the ice-stream the assemblages range outwards, from a subglacial depositional assemblage, characterised by drumlin swarms; through a subglacial erosional assemblage, marked by prominent bedrock scours and large subglacial rock channels; through an ice-marginal assemblage, identified by closely spaced, glaciotectonised push moraines and intervening marginal sandur troughs; into a freely expanding proglacial sandur and lacustrine delta assemblage. The ice-marginal assemblage provides evidence for numerous oscillatory episodes during retreat and at least 20 ice-marginal limits can be identified. At least 11 of these display multiple criteria for identifying readvance and, in the ideal case, is characterised by a moraine form built by localised tectonic stacking of diamict to the rear, fronted by a clastic wedge of ice-front alluvial fan gravel and intercalated flow till. The distribution of sediment–landform assemblages suggests a highly dynamic, convergent ice-stream flow pattern, with high ice velocity, a sharply delineated lateral shear margin, pervasive ice-marginal glaciotectonic deformation and a tightly focused ice-marginal sediment delivery system; all signature characteristics of contemporary ice streams.

Sedimentology, stratigraphy, and glacier dynamics, western Scottish Highlands

Glacial sediments of the western Scottish Highlands are comprehensively described and characterized here for the first time, enabling the first glacial stratigraphy for the area to be proposed. This classification is based on the results of extensive geological mapping and field investigation of sedimentary sequences and their structures, X-ray diffraction and particle size distribution analyses, and comparison with deposits formed in contemporary glaciated environments. These new data are subsequently appraised in terms of their implications for late Pleistocene glacier evolution and dynamics. Together, the data suggest that much of the landscape is palimpsest, and can be attributed to the Weichselian (Late Devensian) glaciation. Subsequent glacier advance during the Younger Dryas did little to modify the area, suggesting that ice flow was dominated by sliding on a meltwater-lubricated rigid bed, with deformation of basal sediments playing a more limited role. Final deglaciation was marked by a significant increase in basal meltwater flux, reflecting the warming climate and increasing precipitation. These new palaeoglaciological and palaeoenvironmental insights advance our understanding of former glacier dynamics in the western Scottish Highlands, improve our knowledge of Pleistocene landscape evolution of this area, and enable comparisons to be made with sedimentary sequences elsewhere.

The Pleistocene glaciations of eastern Yorkshire: a review

SUMMARY The Pleistocene deposits of eastern Yorkshire and adjacent areas have been studied intensively for about 150 years, but numerous problems of dating and correlation remain. Holderness provides the British type site for deposits of the Last Glacial Maximum (the Dimlington Stadial, part of Marine Isotope Stage 2) here dated to between 18,500 and 13,000 radiocarbon years ( c. 23,000–15,000 calendar years) BP, but older glacial deposits are still very difficult to date precisely. An earlier Devensian glaciation of east Lincolnshire and south-west Yorkshire has been suggested, but remains uncertain. The most extensive pre-Devensian glacial deposit is the Basement Till of Holderness and other eastern coastal areas. This is overlain by the raised beach of the Ipswichian Stage (MIS 5e; 128,000–117,000 years ago) at Sewerby, by the pre-Ipswichian Calcethorpe Till at Welton-le-Wold, Lincolnshire, and by boulders weathered in interglacial conditions at Warren House Gill, Durham, so it was deposited during MIS 6 or an earlier cold stage. Late Devensian (MIS 2) amino-acid dates for marine shells from the Basement Till at Dimlington may be explained by intrusion during subglacial disturbance of the till’s upper layers by the Late Devensian glacier. In coastal areas of east Yorkshire, the Skipsea and Withernsea tills and their equivalents between Flamborough Head and the Tees Estuary are attributed to the Dimlington Stadial, and there is considerable evidence that they were deposited by a single surge of a two-tiered ice sheet. The lower (Skipsea) tier originated in south-east Scotland and north-east England, and the upper (Withernsea) tier from Lake District ice that crossed the Pennines via the Stainmore Gap and overrode the Skipsea Till glacier in the Lower Tees Valley area. Stainmore ice was also diverted southwards into the Vale of York. The patchy 'Older Drift' in the Vale of York (mainly grey till with Permian, Carboniferous and Lake District erratics) was also deposited by Stainmore ice flowing southwards, probably in MIS 12.

Geomorphological signature and flow dynamics of The Minch palaeo‐ice stream, northwest Scotland

AbstractLarge‐scale streamlined glacial landforms are identified in 11 areas of northwest Scotland, from the Isle of Skye in the south to the Butt of Lewis in the north. These ice‐directional features occur in bedrock and superficial deposits, generally below 350 m above sea level, and where best developed have elongation ratios of >20:1. Sidescan sonar and multibeam echo‐sounding data from The Minch show elongate streamlined ridges and grooves on the seabed, with elongation ratios of up to 70:1. These bedforms are interpreted as mega‐scale glacial lineations. All the features identified formed beneath The Minch palaeo‐ice stream which was ca. 200 km long, up to 50 km wide and drained ca. 15 000 km2 of the northwest sector of the last British‐Irish Ice Sheet (Late Devensian Glaciation). Nine ice‐stream tributaries and palaeo‐onset zones are also identified, on the basis of geomorphological evidence. The spatial distribution and pattern of streamlined bedforms around The Minch has enabled the catchment, flow paths and basal shear stresses of the palaeo‐ice stream and its tributaries to be tentatively reconstructed. © British Geological Survey/Natural Environment Research Council copyright 2007. Reproduced with the permission of BGS/NERC. Published by John Wiley & Sons, Ltd.

Preliminary investigations of outwash environments in the Tyne Valley: implications for Late Devensian (Dimlington Stadial) deglaciation

Whilst recent detailed sedimentological investigations have been carried out on deglacial valley fill sediments of Late Pleistocene age in many UK river valleys, there is a paucity of high-resolution work on the deglacial history of the Tyne Valley. Combined with a poorly resolved chronology, this represents an appreciable gap in our understanding of Devensian palaeoenvironments in northeastern Britain. Confusion still exists in terms of understanding the mode of deglaciation and the resulting depositional landforms that characterize the present-day morphology of the valley. This paper reconstructs part of the deglacial history of the lower Tyne Valley using information gathered through a combination of geomorphological mapping and description and interpretation of sedimentary sequences. The evidence indicates the sediments are glaciofluvial in origin, deposited within a supra-glacial, rather than sub-glacial environment. Further work currently underway, including the development of a rigorous geochronology based on optically stimulated luminescence (OSL) will help to place these deposits within a secure, regional model of deglaciation, which can be compared with other models developed for adjacent areas of northern Britain.

Late Devensian and Holocene relative sea‐level changes on the Isle of Skye, Scotland, UK

AbstractDetailed litho‐ and biostratigraphical analyses from three coastal sites in contrasting coastal settings on the Isle of Skye, Scotland, UK, reveal evidence for several changes in relative sea level during the Late Devensian and Holocene. At the start of the record, relative sea level in the area was high at ca. 12 500 14C (ca. 14 800 cal.) yr BP but then fell, reaching a low point during the Younger Dryas, at ca. 11 000–10 000 14C (ca. 13 000–11 600 cal.) yr BP, when a rock platform, correlated with the Main Rock Platform, was formed. In the early–middle Holocene, relative sea level was rising by ca. 8000 14C (ca. 8800 cal.) yr BP and in northeast Skye a lagoonal surface, correlated with the Main Postglacial Shoreline, was formed at ca. 6600 14C (ca. 7500 cal.) yr BP. By the late Holocene, relative sea level was again falling, but a rise, registered at at least two sites, began probably before ca. 4000 14C (ca. 4500 cal.) yr BP, and a second lagoonal surface in northeast Skye, correlated with the Blairdrummond Shoreline, was formed, although by ca. 3000 14C (ca. 3200 cal.) yr BP relative sea level in the area had resumed its downward trend. The pattern of relative sea‐level changes disclosed is compared with evidence elsewhere in Scotland. Copyright © 2006 John Wiley & Sons, Ltd.

The Late Devensian terminal moraine ridge at Garret Hill, Stiffkey valley, north Norfolk, England

SUMMARY Glacial stratigraphy and ice-marginal processes within the limit of the Late Devensian Glaciation in eastern England were investigated at Garret Hill, situated on the eastern flank of the Stiffkey valley, north Norfolk. Glacial sediments are divided into four lithofacies units. LFA-1 and 2 consist of chalk-rich diamicton and flint-rich outwash deposits, respectively. These extend beyond the Late Devensian ice-limit and are attributed to glaciation during the Middle Pleistocene. LFA-3 and 4 comprise a red diamicton and meltwater deposits that are equated to the Holkham Till and Ringstead Sand and Gravel respectively, deposited during the Late Devensian Glaciation. It is proposed that a terminal moraine ridge was formed during the Late Devensian Glaciation as a Scottish-sourced ice sheet flowed southwards along the western margin of the North Sea Basin. The moraine is identified by the distribution of ridges and hummocks that border the outcrop of Holkham Till. At Garret Hill, these landforms contain folded chalk-rich diamicton (LFA-1) and flint-rich outwash sediments (LFA-2) overlain by Holkham Till. This event is likely to have been accompanied by the formation of glacial lakes in the Stiffkey valley, impounded between the blocking ice sheet to the north and the Cromer Ridge to the south. The site is only the second site where the Holkham Till has been found overlying glacial deposits of Middle Pleistocene age.

Landslide geomorphology of Cayton Bay, North Yorkshire, UK

SUMMARY The geomorphology of a large coastal landslide complex at Cayton Bay, North Yorkshire, is described. The area inland of the complex is occupied by a main road and a number of properties, so knowledge of current and possible future landslide behaviour is important for planning and risk assessment. Instability at the site is associated with a number of faults that bring argillaceous Upper Jurassic rocks to sea level. These soft rocks are overlain by more resistant sandstones. The sequence is capped by a thick and variable succession of glacial sediments, comprising tills with interbedded sand and gravel lenses that were deposited during the Dimlington Stadial of the Late Devensian. In connection with a study aimed at understanding cliff instability and recession, coastal erosion and the risk to people and assets at Cayton Bay, detailed geomorphological field mapping was conducted. This identified two major landslide systems, which include a periodically active mudslide complex at Cayton Cliff, recognized by shallow scarps and benches with occasional back-tilted blocks, and an area of dormant, deep-seated landslides at Tenants’ Cliffs, which includes a number of graben and horst structures. The origins of the landslides are unclear, but probably involved a variety of processes that led to a reduction in material shear strength or increases in pore water pressures. The original failure probably occurred in the middle Holocene, around 3000 years ago, when sea level reached its approximate current position. This would have initiated erosion of Jurassic argillaceous rocks (Oxford Clay) now exposed at sea level on the coast, and probable deep-seated failure of the overlying, more competent strata (Lower Calcareous Grit). Alternatively, it is possible that retreat of the Late Devensian ice sheet triggered instability, and that the landslide complex is a paraglacial landform produced during deglaciation, around 13 000 years BP. However sea levels were then lower so erosion of the Oxford Clay is unlikely to have been a factor in its development. Contemporary instability is likely to be due to the combined effects of coastal erosion and high groundwater levels, both of which are predicted to increase in the future due to the impact of climate change, implying an increased risk to coastal assets and a need to manage and mitigate such risks.

Geomorphic evidence for active and inactive phases of Late Devensian ice in north-central Ireland

In the Clogher Valley, north-central Ireland, subglacial and proglacial landforms provide evidence for phases of active and inactive subglacial and ice-marginal processes during the Late Devensian (Weichselian) glaciation (∼22–13 kyr BP). Patterns of subglacial Rogen moraines and drumlins record east to west ice flow along the valley axis during maximal ice stages. Eskers, superimposed upon the Rogen moraines and drumlins, record later west to east ice flow and mark the first stages of ice retreat. Areas of large, ice-marginal, non-aligned ridges and mounds are separated by more extensive areas in which no deglacial landforms or sediments are present. The non-aligned ridges and mounds do not show a dominant directional signature, have intricate basal outlines, steep slopes and high relief (< 25 m), and are morphologically associated with meltwater channels and deep enclosed depressions (kettleholes). The ridges and mounds are interpreted as ice-marginal moraines formed by a combination of proglacial thrusting and gravity processes (high sediment mobility) during the melting out of buried ice blocks. An alternative model may involve sediment transport by glacially-driven, groundwater fluxes forming so-called ‘extrusion moraines’. Both models suggest that basal ice was polythermal in character and that alternating active (thrusting) and passive (stagnation) processes at the ice margin took place during overall westward ice retreat.

Dimensions and deglacial chronology of the Outer Hebrides Ice Cap, northwest Scotland: implications of cosmic ray exposure dating

AbstractCosmic ray exposure ages of frost‐weathered bedrock from mountain summits in the Outer Hebrides exceed the age of Late Devensian glaciation. Exposure ages of most glacially‐abraded bedrock surfaces at low and intermediate elevations are younger than the age of maximum Late Devensian glaciation. These results confirm that previously mapped periglacial trimlines in the Outer Hebrides define the upper limit of bedrock erosion by Late Devensian ice. They are consistent with the interpretation, based on geomorphological evidence, that the trimlines mark the approximate upper limit of a Late Devensian Outer Hebrides Ice Cap. A postglacial exposure age from the summit of Oreval (662 m) suggests that this mountain was overrun during the last glaciation, indicating thicker ice cover and a lower surface gradient west of the ice‐cap divide than previously inferred. Although bedrock surfaces below the trimlines are strongly ice‐moulded, some show evidence of prior cosmic ray exposure, which we attribute to limited erosion during Late Devensian glaciation. If this interpretation is correct, the youngest apparent ages from these surfaces give the most reliable dates for deglaciation, at ca. 14.5–14 ka. This implies that ice persisted at favourable sites through the warm opening phase of the Windermere Interstade. Comparison with radiocarbon‐dated evidence from offshore cores suggests net ice margin retreat of ∼74 km eastwards across the adjacent shelf in &gt; 2.3 ± 1.0 ka. The dating evidence is consistent with relatively rapid retreat of calving margins to the coast, then slower withdrawal of ice margins to high ground. Copyright © 2005 John Wiley &amp; Sons, Ltd.

Palaeoenvironmental interpretation of an ice-contact glacial lake succession: an example from the late Devensian of southwest Wales, UK

During the late Devensian (late Weichselian) glaciation, a number of large proglacial lakes developed in dammed river valleys along the southwest coast of Wales, U.K. This paper presents sedimentological data, together with a Digital Terrain Model, to establish the sedimentation history, dynamics and evolution of the largest lake, glacial Llyn (Lake) Teifi. Buried valley-fill sequences within the margins of the former lake basin reveal a thick succession of glaciolacustrine muds which coarsen upward into, or are locally abruptly overlain by, proximal deltaic, subglacial and glaciofluvial deposits. Sediment delivery pathways represented in the lacustrine succession include gravity flows, suspension settling, deltaic aggradation and iceberg rafting, the latter indicating ice-contact conditions. The lacustrine muds are variably deformed, with a range of syn- and post-depositional structures, some of which indicate subglacial deformation associated with overriding of the lacustrine succession. Syn-depositional structures indicate high sedimentation rates, which may explain an absence of bioturbation structures. The overall coarsening-upward succession and cap of subglacial and/or glaciofluvial deposits support recent theories suggesting that glacial Llyn Teifi formed during glacial advance. There is no evidence to support glaciomarine conditions of sedimentation in this area of the Irish Sea basin.

A provisional Quaternary and Neogene lithostratigraphical framework for Great Britain

AbstractThis paper presents an overview of a provisional lithostratigraphical framework for the Quaternary and Neogene deposits of Great Britain (England, Scotland and Wales) (onshore). The objective is to provide a workable framework to aid future Quaternary mapping and research, and a stratigraphical scheme capable of use in a wide variety of applications. Using the full hierarchy, a supergroup, group and subgroup lithostratigraphy, based upon the primary mapping unit, the formation, is proposed. It is recommended that some classes of lithogenetically-defined deposits which, at present cannot be accorded formational status, should be assigned informally to one of the proposed groups or subgroups. The framework distinguishes one superficial deposits supergroup within which seven groups are defined: i) Crag Group, marine deposits (Late Pliocene to Early Pleistocene); ii), Dunwich Group, fluvial deposits (pre-Anglian/pre-Elsterian); iii) Residual Deposits Group; iv) British Coastal Deposits Group, coastal and marine deposits (Anglian to Holocene); v) Britannia Catchments Group, fluvial, organic and mass movement deposits (Anglian to Holocene) within broadly defined catchment areas related to Late Devensian to present-day physiography; vi) Albion Glacigenic Group, glacigenic deposits (pre-Devensian/pre-Weichselian), and vii) Caledonia Glacigenic Group, glacigenic deposits (Devensian/Weichselian). North of the Devensian (Weichselian) ice-sheet limit, a series of glacigenic subgroups are defined geographically for the two glacigenic groups on the basis of mappable formations of till. The subgroups include associated formations of glaciofluvial and glaciolacustrine deposits. Consequently some of the glacigenic water-lain units may extend beyond the Devensian limit. Catchment subgroups of the Britannia Catchments Group are proposed for formations and lithogenetic units defined within broad present-day physiographic regions by major river drainage systems that have developed since Middle Pleistocene time. Lithostratigraphical description and correlation of formations will aid the refinement of the proposed framework and enable the development of lithostratigraphical maps and three-dimensional models. As well as offering a unified framework for onshore Quaternary and Neogene deposits the proposed supergroup, group and subgroup structure may prove useful for a wide range of regional applications (e.g. hydrological, hydrogeological, engineering).

The Minch palaeo-ice stream, NW sector of the British–Irish Ice Sheet

Geophysical data from the UK continental shelf off NW Scotland reveal strongly parallel subglacial bedforms on the sea bed. Field mapping on the adjacent landmass has identified closely spaced bedrock megagrooves and highly elongate drumlinoid forms. All these mega-scale glacial lineations probably formed beneath the same fast-flowing zone of the last British–Irish Ice Sheet, The Minch palaeo-ice stream. This ice stream drained the NW sector of the British–Irish Ice Sheet during the Late Devensian Glaciation (marine isotope stage 2) and terminated near the edge of the continental shelf. The size of the adjacent trough-mouth Sula Sgeir Fan and the presence of buried mega-scale glacial lineations within the Quaternary stratigraphic record imply that fast ice-sheet flow in The Minch has been a feature of several mid- to late Pleistocene glaciations.

Bedrock megagrooves in Assynt, NW Scotland

Geological mapping in Assynt, NW Scotland, has identified three areas of large-scale, linear, bedrock grooving. These closely spaced, subparallel, megagrooves occur predominantly on Cambrian quartzite, are not structurally controlled, and trend generally in the direction of palaeo-ice flow. On the basis of geomorphological evidence, most notably erosional relationships and s-forms, it is proposed that the megagrooves formed at the base of the last (Main Late Devensian) ice sheet and are chiefly the result of high-energy subglacial meltwater erosion. The unusual concentration of bedrock-cut Nye channels in Assynt indicates the presence of large volumes of meltwater beneath the last ice sheet in this region of NW Scotland. This high discharge of meltwater was probably accompanied by localized fast ice-sheet flow, akin to present-day ice streams. It is suggested that bedrock megagrooves may be the geomorphological signature of ice-stream onset zones.

Fluvial system response to Late Devensian (Weichselian) aridity, Baston, Lincolnshire, England

AbstractLittle is known about the impact of Late Devensian (Weichselian) aridity on lowland British landscapes, largely because they lack the widespread coversand deposits of the adjacent continent. The concentration of large interformational ice‐wedge casts in the upper part of many Devensian fluvial sequences suggests that fluvial activity may have decreased considerably during this time. The development of optically stimulated luminescence (OSL) dating enables this period of ice‐wedge cast formation to be constrained for the first time in eastern England, where a marked horizon of ice‐wedge casts is found between two distinctive dateable facies associations. Contrasts between this horizon and adjacent sediments show clear changes in environment and fluvial system behaviour in response to changing water supply, in line with palaeontological evidence. In addition to providing chronological control on the period of ice‐wedge formation, the study shows good agreement of the radiocarbon and OSL dating techniques during the Middle and Late Devensian, with direct comparison of these techniques beyond 15 000 yr for the first time in Britain. It is suggested that aridity during the Late Devensian forced a significant decrease in fluvial activity compared with preceding and following periods, initiating a system with low peak flows and widespread permafrost development. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Hydrological factors in the interpretation of stable isotopic proxy data present and past: a European perspective

In the context of this paper, stable isotopic proxies are those preserving directly, or via known or calculable fractionation factors, a record of 18O/ 16O and/or 2H/ 1H in the water which contributed to their growth. Suitable proxies include amongst others tree-ring cellulose, bone phosphate, lake sediment minerals and speleothem fluid inclusions. A principal aim of studying isotopic proxies is to gain more information about past climates through a knowledge of how rainfall isotope compositions have changed over time. However, converting back from proxy to rainfall is not necessarily straightforward, because however well the isotopic fractionation due to proxy growth or formation is understood, a variety of modifying processes may have intervened between this and the actual rainfall events. Three main reservoirs of environmental water may contribute to the isotopic compositions of terrestrial proxy indicators: surface waters, soil moisture, and groundwater. Each of these can in principle be isotopically modified compared to rainfall in the locality. This review examines these effects and how they may change under different European climate types at the present day. It is concluded that while groundwater isotopic compositions typically represent closely the bulk composition of rainfall under a variety of climatic regimes, soil and particularly lake waters require detailed study if their isotope systematics are to be adequately understood. The review also finds that to a large extent “the present is the key to the past” in terms of recharge processes during the late Pleistocene, though glaciation may have had profound isotopic consequences in certain areas, while a more general aridity led to the apparent absence of recharge in most areas for much of the late Devensian.

Windpolished boulders and bedrock in the Scottish Highlands: evidence and implications of Late Devensian wind activity

The present day maritime climate of Scotland is primarily characterized by strong winds which, in very exposed sites, lead to modern windpolish of rock surfaces. The widespread existence of in situ relict windpolished boulders and bedrock surfaces in Scotland has enabled a reconstruction of prevalent Late Devensian (Late Weichselian) including Loch Lomond Stadial (Younger Dryas) palaeo‐wind directions. Previous reconstructions of palaeo‐wind directions have been indirect and based mainly on the distribution of aeolian sediments and former glaciers. Observations of relict windpolished microforms and their distribution on boulders and bedrock outcrops on various rock types at 55 sites in different parts of the Scottish Highlands have been used to establish a palaeo‐wind map for the area. The reconstruction indicates two sets of dominating wind directions, one between SE and SW and one between NW and N. The maximum age of the windpolish is 16–10 cal. ka BP, but most of it presumably developed during the Loch Lomond Stadial 13–12 cal. ka BP, inferred from the distribution of windpolish sites in relation to the deglaciation chronology and establishment of vegetation.

Stoke Newington: geoarchaeology of the Palaeolithic ‘floor’

The archaeological importance of Stoke Newington lies in the recognition there in the nineteenth century of a Palaeolithic occupation horizon. Several attempts have been made in the last thirty years to relocate this horizon, but without success. A review of the nineteenth century accounts and of more recent investigations suggests that any evidence of Palaeolithic occupation is unlikely to be present as a simple, unique and readily traceable surface. The findings point to occupation, probably episodic, within Marine Isotope Stage 9 (MIS 9) during a period of fluvial aggradation. The evidence also suggests that the height range of the aggradational sediments, termed here the Stoke Newington Sands, is overlapped by sediments of a later and separate MIS 9 aggradation comprising the Highbury Silts and Sands, and by Late Devensian and Holocene sediments of the Hackney Brook, giving rise to a complex local stratigraphy.