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Towards the end of the last glaciation, ice sourced from the western Grampian Mountains of Scotland flowed down Strath Spey to encroach on the northern flanks of the Cairngorm Mountains. The maximum of this late advance and its subsequent retreat is recorded by moraines, ice-marginal meltwater channels, and kame terraces that can be traced for 60 km along Strath Spey. New cosmogenic Be-10 exposure ages from moraines indicate deglaciation at 15.1 +/- 1.1 ka. This timing matches closely the recalibrated mean ages of 14.7 +/- 0.7 and 15.2 +/- 0.7 ka for the Wester Ross Readvance in the North-West Highlands. A synchronous readvance of the British-Irish Ice Sheet (BIIS) towards the end of Greenland Stadial 2a (GS-2a) (16.9-14.7 ka) is indicated. Thereafter active ice retreat from the flanks of Strath Spey was rapid, occurring within the similar to 1 ka uncertainty of the cosmogenic exposure ages. We suggest the advance followed the collapse of the marine parts of the BIIS at similar to 16 ka due to conditions of increased precipitation occurring at a time of low temperatures. The rapidity of deglaciation may reflect enhanced Fohn effects caused by the ice dome in the western Grampians.

Three separate till units are recognized on Orkney deposited during the last ice sheet glaciation: the Digger, Scara Taing and Quendal Till members. The Digger Till records an ice advance fromthe south that extended on to the Atlantic shelf. The Scara Taing Till records a later period of full ice cover when ice moved from the SE out of the Moray Firth and reached Last Glacial Maximum (LGM) limits on the shelf edge. The Quendal Till records a late phase of ice sheet flow from the SE to limits c. 20 km west of Orkney. No till unit or flow set has been identified to confirm the presence of a local ice cap on southern Orkney during the last glaciation. Whilst the blocking presence of the Fennoscandian Ice Sheet (FIS) and the Shetland Ice Cap may have contributed to the deflection of ice flow over Orkney, similar flow patterns also occurred before and after the LGM. Scandinavian erratics on northern Orkney are probably reworked and provide no direct support for the passage of the FIS. Middle to Late Carboniferous palynomorphs found in tills in eastern Orkney may have been reworked from nearby Permian mudstones.

This paper reviews existing information on the last glaciation of Caithness and presents new evidence for additional till units and for long distance ice-flow paths based on till palynomorphs, indicator erratics and striae. Early, radial expansion of Northern Highland ice probably occurred at 31 - 29 ka. After ice withdrawal from the north coast, Moray Firth ice returned before a second withdrawal. Thereafter Moray Firth ice advanced to limits close to the Atlantic shelf edge between 21 and 18 ka. Deglaciation of hill summits was completed by 18.4 - 17.8 ka but the low ground south of Wick only became ice free after 16.5 ka. Recognition of these multiple ice-flow events is consistent with the dynamic behaviour of the last ice sheet exhibited in mathematical simulations. The event sequence differs, however, from nineteenth century and recent two-stage flow set reconstructions as each main flow set is shown to represent multiple events following similar paths but under different ice sheet configurations. Various configurations allow ice to flow northwards across Caithness and so remove any requirement for the Fennoscandian Ice Sheet to directly block and divert the outflow of ice from the Moray Firth during the last glaciation.

A collection from the principal records in the "archives" of Graham Balcombe on the events leading to the foundation of the Cave Dving Group and notebook records of the early "ops." in which he took part.

Much previous work on Late Cenozoic glacial erosion patterns in bedrock has focussed on mountain areas. Here we identify varying impacts of ice sheet erosion on the low-relief bedrock surface of the Fennoscandian shield, and examine the geological, topographical and glaciological controls on these patterns. We combine GIS-mapping of topographical, hydrological and weathering data with field observations. We identify and investigate areas with similar geology and general low relief that show different degrees of ice sheet erosional impact, despite similar ice cover histories. On two transects with a total area of ~ 84 000 km2 across the northern Fennoscandian shield, we first establish patterns of glacial erosion and then examine why glacially streamlined areas exist adjacent to areas of negligible glacial erosion. The northern transect includes two areas of exceptional glacial preservation, the Parkajoki area in Sweden and the so-called ice divide zone in Finland, each of which preserve tors and deep saprolite covers. The southern transect, overlapping in the northern part with the first transect, includes areas of well developed glacial streamlining, with bedrock areas stripped of loose material and barely any weathering remnants. For both areas, we firstly present contrasting indicators for ice sheet erosional impact: streamlined and non-streamlined inselbergs; parallel and dendritic/rectangular drainage patterns; and the absence and presence of Neogene weathering remnants. This is followed by an investigation of factors that possibly influence ice sheet erosional impact: ice cover history, ice cover duration and thickness, bedrock type and structure, and topography. We find that the erosional impact of the Fennoscandian ice sheet has varied across the study area. Distinct zones of ice sheet erosion are identified in which indicators of either low or high erosion coexist in the same parts of the transects. No direct impact of rock type on glacial erosion patterns

Europe’s largest Fe oxide deposits are hosted in Palaeoproterozoic supracrustal rock of the Fennoscandian Shield in the northern Norrbotten province, Sweden. Significant clay alteration zones occur at the present land surface and at depth in the Kiirunavaara, Malmberget, Gruvberget, Leveäniemi and Mertainen iron oxide-apatite deposits that are hosted in Svecofennian, mostly intermediate to acid volcanic and subvolcanic rocks, but also in the vicinity of skarn-rich iron formations in the upper part of the older Karelian Greenstone group. A whitish, up to 30 m thick, soft clay alteration zone below glacial till was discovered in 1977 to 1979 by geophysical survey, trenching and drilling in the Vathanvaara area that hosts several prospects in skarn-rich iron formations. The <6 µm fractions of the altered rocks consist predominantly of a dioctahedral Mg-bearing, Al-rich, but Fe-free sodium smectite with minor amounts of an interstratified chlorite-smectite mineral, chlorite, zeolite minerals of the stilbite group and residual albite and actinolite. Whitish to greenish clay alteration zones that can reach a thickness of at least 50 m are encountered in association with the southern part of the Kiirunavaara ore body at a depth of more than 1 km. In part, alteration is pervasive, in part it occurs along multiple fractures or near breccias. The clays can be soft and hard. They occur within the ores and along the contacts with the ore, but also as isolated masses in the hanging wall and the footwall several tens of meters away from the ore. The clay fractions consist mainly of Mg-bearing, Al-rich sodium smectites that shows no signs of interstratification. At the contact, or within the ore, additionally residual green Fe-rich chlorite, phlogopite, talc, albite, sulfides (pyrite and chalcopyrite), and rare calcite in the altered rocks was observed. Stable hydrogen and oxygen isotope data of sodium smectites from Vathanvaara clearly indicate a low-temperature hydrothermal

Much previous work on Late Cenozoic glacial erosion patterns in bedrock has focussed on mountain areas. We here identify varying impacts of ice sheet erosion on the low-relief bedrock surface of the Fennoscandian shield, and examine the geological, topographical and glaciological controls on these patterns. We combine GIS-mapping of topographical, hydrological and weathering data with field observations. We identify and investigate areas with similar geology and general low relief that show different degrees of ice sheet erosional impact, despite similar ice cover histories. On two transects with a total area of ~84 000km2 across the northern Fennoscandian shield, we first establish patterns of glacial erosion and then examine why glacially streamlined areas exist adjacent to areas of negligible glacial erosion. The northern transect includes two areas of exceptional glacial preservation, the Parkajoki area in Sweden and the so-called ice divide zone in Finland, each of which preserve tors and deep saprolite covers. The southern transect, overlapping in the northern part with the first transect, includes areas of intense glacial streamlining, with bedrock areas stripped of loose material and barely any weathering remnants. For both areas, we firstly present the indicators we have availabe for ice sheet erosional impact: streamlined and non-streamlined inselbergs; parallel and dendritic/rectangular drainage patterns; the absence and presence of Neogene weathering remnants. This is followed by an investigation of factors that possibly influence ice sheet erosional impact: (pre-glacial) land surface elevation and topography, bedrock type and structure, and the ice cover history. We find that the extreme preservation of pre-glacial relief in certain parts of the study area is likely explained by repeatedly divergent flow and frozen-based conditions, and that the most likely control causing glacial streamlining and strong erosion was acceleration of flow around major o

The erosional effect of ice sheets on shield bedrock surfaces has been debated for many decades. Whilst there seems to be agreement that ice sheet erosion of the bedrock landforms was generally modest, and that many preglacial landscape elements remain, we need to know which factors influence ice sheet dynamics and erosional impact on the shield. Using GIS-analysis and field observations, combined with cosmogenic exposure ages, we investigate areas with a similar ice cover history but with greatly different degrees of glacial erosional impact. On two transects with an area of ~35 000km2 each across the shield, we examine why glacially eroded areas exist adjacent to areas of negligible glacial erosion. Firstly, a E-W transect, identifies two areas of exceptional glacial preservation, the Parkajoki area in Sweden and the so-called ice shed zone in Finland, each with large tors and deep saprolite covers. Secondly a NW-SE transect, overlapping in the northern part with the first transect, includes areas of intense glacial streamlining, with bedrock areas stripped of loose material and barely any weathering remnants. For areas of negligible and advanced glacial erosion, we investigate geology, elevation, topography, hydrology and duration of ice cover in an attempt to identify factors leading to ice sheet erosion/preservation of the underlying shield landscape. We estimate the duration of ice cover from the known ice cover history. We use a single flow path and thereby use steady glaciological parameters. Our results point to glacial bedrock erosion of flat shield surfaces in the range of tens of meters. Erosion only happens in areas where the ice is forced to flow around obstacles or into basins. These preglacial landscape properties are in turn determined by bedrock geology and long-term geomorphic and tectonic evolution. Consequently, a combination of bedrock type and topography determines ice sheet properties and thereby effects of ice erosion on shield surfaces.

The question of whether the Shetland Islands were covered by an ice cap or by an ice sheet during the last glacial cycle (40-10 ka) remains unresolved. This paper addresses this problem using existing and new data on glacial erratic carry, striae, glacial lineaments and roche moutonnee asymmetry. Its focus is on eastern Shetland, where ice-cap and ice-sheet glaciation would lead to opposed ice-flow directions, towards and away from the North Sea. Evidence cited in support of ice-sheet glaciation of Shetland is questioned. The primary survey of striae correctly identified striae orientation but the direction of ice flow from striae on eastern Shetland was misinterpreted: it was not from, but towards the North Sea. Glacial lineaments interpolated to cross the spine of Shetland instead are discontinuous and diverge away from an axial ice-shed zone that lacks lineaments. Glacitectonic structures cited recently as evidence for westward flow of an ice sheet across eastern Shetland have been partly misinterpreted and other ice-flow indicators in the vicinity of key sites indicate former eastward ice flow towards the North Sea. Westward carry of erratics over short distances in N and S Shetland may be partly accounted for by shifts in ice sheds during ice-cap deglaciation. Collectively, the evidence for movement of the Fennoscandian ice sheet across Shetland is weak. Any ice-sheet incursion over Shetland occurred before the last glacial cycle. The cleansed ice-flow directional data for Shetland show a simple pattern of divergent ice flow from an axial ice-shed zone beneath an ice cap. The deglaciation sequence for the ice cap is evident from sea-bed moraine systems. The Shetland ice cap at the Last Glacial Maximum was substantial, attaining a thickness of 1 km and a diameter of >160 km. The ice cap was of sufficient size to restrain the Fennoscandian ice sheet on the western edge of the Norwegian Channel and to divert the British ice sheet over Orkney. Glacial landscapes, AuthorCount:1

We investigate the long-term geomorphological evolution of the inselberg plains on the glaciated northern Fennoscandian shield. The shield surface has been largely stripped of pre-Quaternary correlative sediments and saprolites by non-glacial and glacial erosion, which makes investigations of pre-Quaternary landscape development a challenge. The relief of the study area, covering 33,000 km3 in the centre of the shield in northern Sweden, includes an abundance of inselbergs that provide the basis for the study. We examine the relief of the inselberg plains, integrated with glacial-geomorphologic features, geology, and weathering remnants, by using GIS-analysis and fieldwork. Several key areas are used to demonstrate the impact of glaciations on the large scale relief, and the influence of geology, structure and deep weathering on relief formation. Glacial erosion had only a minor impact on the large-scale bedrock morphology of northern Sweden. Based on excavations and observations in the Parkajoki area, an area largely preserved under cold-based ice during Quaternary glaciations, we infer that grus weathering, resulting in saprolite covers of up to 10-20 m thickness, occurred in the Neogene. However, inselbergs are considerably higher than that, and must therefore be the result of older deep weathering and erosional events. Narrow fracture zones associated with deep kaolins found in northern Fennoscandia may represent the roots of older generations of deep weathering covers but their age and formation is yet unclear. The geology of the area has greatly influenced the present surface relief. The positions and footprints of the inselbergs are often closely controlled by bedrock type and fracturing. Granite inselbergs generally have dome forms where dome shape and slopes are determined by joint patterns. Steps between palaeosurfaces locally coincide with lithological boundaries and major faults. These links indicate the fundamental importance of etch processes in shapi

Stepped relief is a characteristic feature of many upland areas on Earth. In this study, we examine if stepped relief can be identified objectively by GIS-analysis of digital elevation models (DEMs). We specifically study the stepped relief landscapes of northern Sweden, comprising areas of contrasting topography in the mountainous northern Scandes and on the inselberg plains of the Precambrian basement east of the Caledonides.We mainly use hypsographic curves to examine the elevation distribution of the study areas and to identify palaeosurfaces. Peaks in the hypsographic curves are interpreted as palaeosurfaces, while hypsographic minima are interpreted as breaks in slope, separating these surfaces. In the northern Scandes, where only patchy remnants of palaeosurfaces remain, we use empirical cutoff values of slope angles to restrict palaeosurface areas to those identified in thefield and in air photos. In addition, air photo andfield mapping of glacially eroded areas is necessary to exclude glacially formed low relief surfaces, such as valley floors. These latter procedures introduce an unavoidable degree of subjectivity to the study. Our results indicate that in the northern Scandes, surfaces with an inclination of 11°, after glacially formed features are abstracted, correspond well with palaeosurface remnants. Breaks in slope separating the surface generations in themountains are centred around 860, 1320, and 1520 masl (above sea level), respectively. On the plains east of the northern Scandes, hypsographic data were filtered to remove inselbergs in order to analyse only the plains. Hypsographic curves of both the filtered and the unfiltered data of the inselberg plains show minima at elevations that correspond to steps separating multiple palaeosurfaces at elevations of 190, 250, and 400 masl. The steps separating the different palaeosurfaces are, in places, aligned with known geological discontinuities, but extensive remnants also transect structure. The pres

We investigate the evolution of a glaciated inselberg landscape in northern Sweden since the late Mesozoic, c. 65 million years ago. The study area is part of the Fennoscandian shield and has been stripped of cover rocks and also largely of weathering mantles by preglacial and glacial erosion to leave low relief inselberg plains, with a thin cover of Quaternary deposits. We use these inselbergs as the basis for study of the impact of glacial and preglacial erosion on the shield landscape. GIS-analyses of digital elevation models (DEMs) enable us to identify the morphometry of the inselbergs. Field mapping and mechanical excavations of inselberg margins allow links to be explored between dome-like granite inselbergs and sheet structures and to examine till and saprolite mantles. Very low glacial erosion in the Parkajoki area allows the final stages of preglacial relief development to be reconstructed for the Late Neogene. The hypsometry of the study area, in combination with inselberg elevation and distribution, allows four palaeosurfaces to be identified. The effects of glacial erosion on the bedrock forms of the inselbergs of the study area were generally restricted to inselberg streamlining by steepening of inselberg flanks. The inselberg landscape relief was enhanced by the removal of saprolite mantles during the Quaternary glaciations. The saprolites formed during the late Neogene, thin or absent close to the inselberg summits and of 10-20 m thickness at the inselberg feet and on the plains. The inselbergs are much older features, however, and deep kaolinization and soft ores are evidence for development by etching from a Mesozoic base level surface. Eocene marine clays on the continuation of the inselberg plains in northern Finland at around 260 m a.s.l. indicate that the inselberg plains above the Pakko palaeosurface generation predate the Paleogene-Eocene thermal maximum. Erosion rates, calculated for two reconstructed summit envelope surfaces, range betwee