bluuebunny/crossref_metadata_2025 huggingface dataset:
Sedimentary environments associated with Glacial Lake Trimingham, Norfolk, UK
Authors: HART JANE K.
Published: July 2010

The site of Trimingham is situated where the Cromer Ridge, the largest topographic feature of northeast Norfolk, transects the coastline, providing an opportunity to study the ridge's internal structure and stratigraphy. It can be demonstrated that there were two glacial advances at this site, with an intervening phase of proglacial lake sedimentation that lasted for approximately 2000 years (Glacial Lake Trimingham). A detailed investigation of the sedimentology of the lake sediments enabled a facies reconstruction showing spatial and temporal changes within this lake. Ice‐sheet retreat is indicated by an upward change from proximal to distal varve sequences, and a general shallowing of the lake followed by the deposition of marl‐rich sediments and then aeolian and/or beach sands. A subsequent readvance of the ice‐sheet is marked by further deposition of varved sediments and then by till deposition. This site provides an opportunity to study enviromental change over a known time period within the Anglian glaciation. It is suggested that this lake formed as the result of two ice‐sheets coalescing and may be associated with the diachronously formed North Sea lake(s).
A boulder beach formed by waves from a calving glacier; Eqip Sermia, West Greenland
Authors: NIELSEN NIELS
Published: July 2010

A large‐scale boulder beach close to a tidal glacier was examined at Eqip Sermia, Disko Bugt, West Greenland, in 1989. Photographs from 1912 and 1929 show an advance of the glacier of more than 1.5 km beyond its present location. Lateral and terminal moraines were formed in the sea, and subaerial parts and their positions can be detected from the old photographs. Today the outermost part of this moraine system has disappeared totally, except for about 1 km of the lateral moraine. The distal 300 m of the still existing moraine apparently has been displaced and transformed into a shape that, in plan view and cross‐section, resembles a barrier spit. The material of the boulder beach consists mainly of coarse clasts with boulders of 1 m to more than 1.5 m in diameter. Distributions of clast sizes and sediment structures on the barrier surface also suggest wave and overwash dynamics as being the responsible agents. Located in the inner part of a fiord system, the fetches are restricted and thus normal waves are very small. Large waves generated by glacier calving, and/or sea‐ice action, are therefore the only processes that can explain the geomorphology and clast distribution of this coastal feature.
Lateglacial and early Holocene lake sediments from the northern Apennines, Italy – pollen stratigraphy and radiocarbon dating
Authors: LOWE J. JOHN
Published: July 2010

Radiocarbon‐dated pollen profiles are presented from two basins in Prato Spilla, near Val Parma in the northern Apennines. One basin contains a complete Holocene succession, the other a full Lateglacial to mid‐Holocene record. The data provide the most comprehensive Lateglacial‐early Holocene pollenstratigraphic succession yet reported from the northern Apennines accompanied by an internally consistent radiocarbon chronology. They provide fresh impetus for (a) a discussion of the strength of the Younger Dryas ‘signal’ in pollen‐stratigraphic profiles from southern Europe, (b) an assessment of the palaeovegetation of northern Italy during the last glacial‐interglacial transition, and (c) the altitude of the snowline in the region during the Younger Dryas.
Late Weichselian marine stratigraphy of the southern Kattegat, Scandinavia: evidence for drainage of the Baltic Ice Lake between 12,700 and 10,300 years BP
Authors: BERGSTEN HELENE , NORDBERG KJELL
Published: July 2010

From stratigraphic investigations of 38 piston and vibro cores, four fine‐grained Late Weichselian sediment units can be defined in the southern Kattegat. A continuous stratigraphic record of the Late Weichselian sediments cannot be established from single cores due to the uneven distribution of the units, but by compilation of relative stratigraphies a composite record can be determined for sediments deposited between approximately 13,500 and 10,000 BP. The sediments contain both lithological and biostratigraphical evidence that the Baltic Ice Lake was suddenly drained through the Öresund Strait at about 12,700 BP. This drainage route appears to have been unchanged until about 10,300 BP when a passage opened in south central Sweden through which the final drainage of the Baltic Ice Lake took place. The Younger Dryas cold event appears to have had only marginal effects on the marine benthic life in the region. The data also indicate that drainage of fresh Baltic water through the Öresund Strait was the driving force for an inflow of marine water from the Skagerrak North Atlantic Ocean into the southern Kattegat, as occurring at the present. This paper is a contribution to IGCP 253, Termination of the Pleistocene.
Early Weichselian interstadial sediments at Härnösand, Sweden
Authors: AMBROSIANI KARIN GARCÍA , ROBERTSSON ANN‐MARIE
Published: July 2010

The till‐covered organic sediments at Härnösand have been resampled and reinvestigated with respect to their micro‐ and macrofossil content. The sediments were deposited in a shallow freshwater basin with a sandy substratum and probably under oligotrophic conditions. The regional vegetation consisted of a shrub or herb tundra, later changing into an open Betula forest with scattered Picea and Larix. In the lake, submerged plants such as Potamogeton filiformis and Isoëtes lacustris grew, together with Carex. On the shores the vegetation consisted of Betula nana, occasional Betula trees, Salix and Selaginella selaginoides. The beetle fauna suggests an average July temperature of 10–11°C. The flora indicates limited leaching and, thus, deposition during a relatively long and warm interstadial is suggested. The Härnösand sediments are subsequently correlated with the Brörup Interstadial.
World atlas of Holocene sea‐level changes
Authors: MÖRNER NILS‐AXEL
Published: July 2010

Book reviewed in this article:

Pirazoli. P. A. 1991: World Atlas of Holocene Sea‐Level Changes
Carbonates, granulometry, and color of tills on the south‐central Canadian Shield and their implications for stratigraphy and radiocarbon dating
Authors: KARROW PAUL F.
Published: July 2010

Till containing over 10% matrix carbonate extends in a belt 200–300 km wide south of the Hudson Bay Paleozoic basin source. The southern boundary is represented by the ‘carbonate line’, extending from Wawa to near Timmins and Cochrane in the study area. Higher silt content and lighter color are associated with the higher carbonate till. The carbonate tine corresponds approximately to the Chapleau moraine and correlative moraines to the northwest and may signify a discrete stratigraphic unit (possibly identifiable with the Matheson Till) formed by a glacial readvance. Glaciolacustrine sediments have higher carbonate content than nearby till and similarly form widespread sediment blankets even beyond that of the carbonate‐rich till. Radiocarbon dating of amorphous organic sediments may be at risk because of old carbon error on such terrain and there may be some risk even in areas of much smaller carbonate content. A greater effort should be made to establish chronologies based on terrestrial plant matter, now more often possible with AMS radiocarbon dating.
Different types of ending to the last two interglacials in western Europe
Authors: LEFEBVRE DOMINIQUE
Published: July 2010

Tidal deposits dating from the penultimate interglacial (Oxygen Isotope Stage 7) are preserved on a bank of the River Seine at Tancarville. The foraminiferal assemblages indicate a gradual cooling towards Arctic conditions, which corresponds to the onset of the penultimate cold period. This cooling started before or during the drop in sea level in Europe, in contrast to the situation at the end of the last interglacial (Eemian) when Europe remained warm even during the period of falling sea level.
Influence of snow upon rates of granodiorite weathering, Colorado Front Range, USA
Authors: BENEDICT JAMES B.
Published: July 2010

Measurements of phenocryst relief in 1‐m2 quadrats placed randomly on southwest‐facing granodiorite outcrops exposed by late Pleistocene deglaciation of a high‐altitude Front Range col suggest that weathering is strongly influenced by snow. Depending upon local differences in snow‐cover duration (inferred from differences in lichen cover), rates of bedrock‐surface lowering vary from 0.0001 to 0.0013 mm/year. A quadratic polynomial best describes the relationship. Weathering is least effective beneath late‐lying snowbanks that protect the rock from freeze‐thaw and wetting‐drying cycles for most of the year, and in winter snow‐free sites where dryness and the binding effects of crustose lichens discourage granular disintegration. Weathering is most effective in areas of thin to moderate winter snow cover where meltout occurs early, moisture is available at critical seasons, and episodic lichen snowkill ensures that bare rock is exposed. If granite‐weathering data are to be used for dating, measurements should be restricted to microenvironments with comparable snow‐accumulation histories.
Water‐eroded crescentic scours and furrows associated with subglacial flutes at Breidamerkurjökull, Iceland
Authors: DREIMANIS ALEKSIS
Published: July 2010

Several subglacially formed short flutes show crescentic scours around the boulders at their proximal end and furrows along their sides. The crescentic scours and furrows are partly filled by sorted sand and gravel. and it is suggested here that they were formed by fast flowing, turbulent meltwater in the subglacial cavity where the flute was formed.
Estimates of Late Glacial and Holocene aeolian activity in Belgium, Poland and Sweden
Authors: MYCIELSKA‐DOWGIAŁŁ ELŻBIETA
Published: July 2010

A set of textural features is proposed as a measure of the degree of transformation of alluvial source deposits into aeolian ones. Analysis of grain‐size distribution, quartz‐grain rounding and frosting. heavy‐mineral and overall mineral composition and micromorphology of quartz‐grain surfaces in dune and source deposits in Poland. Belgium and Sweden, enabled a variable degree of sediment transformation to be distinguished. The degree of transformation is termed degree of aeolization. It is shown to be dependent upon the total duration of aeolian episodes. The degree of aeolization of the dune deposits investigated is highest in Poland, intermediate in Belgium and lowest in Sweden.
Øvre Æråsvatn ‐ palynostratigraphy of a 22,000 to 10,000 BP lacustrine record on Andøya, northern Norway
Authors: ALM TORBJØRN
Published: July 2010

Radiocarbon datings of a 4.10 m long lacustrine sequence from Lake Øvre Æråsvatn reveal continuous sediment accumulation during most of the Late Weichselian. starting before 21.800 ± 410 BP. The pollen record for the period 21,800 to 12,800 RP is uniform and is strongly dominated by Poaceae. Pollen influx variations suggest a succession of climatic ameliorations and deteriorations. Low to Middle Arctic. interstadial conditions prevailed from 21.000 to 19.650 (19.000) BP. A pronounced climatic deterioration followed. culminating at c. 18,85018,500 BP. synchronous with a glacial advance over the nearby Endletvatn and Nedre Æråsvatn basins At c 18.300 BP. a climatic amelioration triggered important changes in the lacustrine environment. Organogenic gyttja (2.56 m) accumulated from 18,300 to 15,000 BP. indicating a eutrophic lacustrine environment. Sparsity of minerogenic material suggests an arid climate with low surface runoff. Further ameliorations occurred from c. 17,400 to 16,800 BP and 16,000 to 15,000 BP. From c. 15.000 BP onwards. a climatic deterioration is indicated. The 17,800 to 10,500 BP record is fragmentary. At c. 10,500 BP. an improving climate induced establishment of Betula nana –Empetrum heaths. rapidly succeeded by mesic Betula pubescens Filipendula woodlands.
A distinct δ13C decline in organic lake sediments at the Pleistocene‐Holocene transition in southern Sweden
Authors: HAMMAKLUND DAN
Published: July 2010

Values of δ13C obtained from conventional bulk sediment radiocarbon dates encompassing the Pleistocene Holocene boundary have been compiled and plotted against 14C age. In all. 286 lake sediment dates from southern Sweden in the range 8.000 to 13.000 BP have been evaluated. A significant decrease in δ13C values, initiated shortly before 10.000 RP and amounting to 5%, is distinguished. This change is accompanied by increased limnic productivity. decreased erosive input and increased organic carbon content of the sediments. A probable explanation for the δ13C decline in organic material is decreased importance of dissolution of silicates at the transition to the Holocene. During the Late Weichselian. extensive weathering of exposed minerogenic material with subsequent input of bicarbonate to the lake water may have caused a relative enrichment of 13C in dissolved inorganic carbon. Furthermore, the early Holocene increase in terrestrial vegetation cover probably led to an increased supply of 13C depleted carbon dioxide to the lake water by root respiration. Altered limnic vegetation, presumably towards increased production of phytoplankton. could also have contributed to the observed decreasing δ13C trend. The importance of these processes compared to other possible influencing factors. mainly endogenic carbonate production and changes in the global carbon cycle. is discussed.
Middle Weichselian marine sediments from eastern Kattegat, Scandinavia
Authors: BERGSTEN HELENE , NORDBERG KJELL
Published: July 2010

Foraminifera, pollen, lithology and radiocarbon dates from a core in the southern Kattegat provide a rare opportunity to obtain data relating to environmental conditions during the Middle Weichselian in the offshore Kattegat. This core is also correlated with an adjacent second core. Redeposited Eemian foraminifera and pollen occur in the Middle Weichselian sediments. This is interpreted as a result of reworking by an active Middle Weichselian ice present in, or advancing from, a northeasterly to easterly direction. During a second phase the Middle Weichselian sediments were compacted, probably a result of overriding by an ice from the northeast during the Middle Weichselian and/or the Late Weichselian Maximum. The Middle Weichselian sequence is overlain by a Holocene sequence which, in turn, is overlain by an admixture of Middle Weichselian and Holocene sediments. This mixing may be a result of tectonic activity some time between 7300 and 1000 BP. The core ends in Holocene fine sediments representing the last c. 1000 years.
Seismic stratigraphy of the Quaternary and its substratum in southeastern Kattegat, Scandinavia
Authors: GYLDENHOLM KELVIN G. , LYKKE‐ANDERSEN HOLGER , LIND GUSTAF
Published: July 2010

Based on c. 1500 km reflection seismic profiles, the Quaternary formations and their pre‐Quaternary substratum in the southeastern Kattegat are described and a geological interpretation is suggested. The major volume of Quaternary deposits is found in a broad north‐northwest south‐southeast trending topographic depression. The substratum consists of Upper Cretaceous limestone in the region north of the Sorgenfrei–Tornquist Zone, and inside this zone older Mesozoic sedimentary rocks and Precambrian crystalline rocks are found. The Quaternary is divided into four seismic units. No direct stratigraphic control is available, but the units are assumed to represent a period ranging from Late Saalian to Holocene. The oldest unit (unit 3) is composed of deposits of supposed Late Saalian to Middle Weichselian age. This unit was severely eroded probably by the Late Weichselian ice sheets in a zone extending 40–50 km from the Swedish coast. Unit 2 represents the Late Weichselian till deposits. North and east of the island of Anholt unit 3 is cut by a system of channels eroded by glacial meltwater. By the erosion a relief up to c. 100 m was formed. After the recession of the Late Weichselian ice, an up to 100 m thick sequence of water‐lain sediments (unit 1) was deposited in the erosional basin and channels. Holocene deposits (unit 0) of considerable thickness have only been identified in the channels in the northern part of the area.
Hydrographic changes in the southern Kattegat (Scandinavia) during the early Holocene transgression
Authors: CHRISTIANSEN CHRISTIAN , CONRADSEN KELD , EMELYANOV EMIL , TRIMONIS EGIS , HEINEMEIER JAN , RUD NIELS
Published: July 2010

Detailed sedimentological, micropalaeontological, mineralogical and geochemical investigations as well as14C datings were carried out on a core from the southern part of the Kattegat Sea. According to the micropalaeontological interpretations, sea level rose by approximately 20 m in the periodc.9610 BP to 8200 BP. The core therefore provides evidence of the hydrographical conditions in the southern Kattegat during the early Holocene transgression. In the sediment there is geochemical evidence of strong stratification in the water column possibly related to inflow of saline water around 9080 BP. After the sediments dated to 8200 BP there is a hiatus followed by very young (<300 BP?) sediments. It is suggested that this hiatus might be associated with the opening of the Danish Straits.
Recent and subrecent sedimentary conditions in the southern part of the North Sea–Baltic Sea transition
Authors: CHRISTIANSEN CHRISTIAN , KUNZENDORF HELMAR , OTTO CHRISTIAN , SENSTIUS JACOB
Published: July 2010

The recent rate of net sedimentation (0–5mm/yr) in the southern Kattegat is to a high degree governed by resuspension. In shallow areas (10–25 m) there is no or very little sedimentation. Sediments here are sandy lag sediments with a low content of organic matter (0.5–3.0%), nitrogen (0–0.1%) and phosphorus (0.01–0.05%). In deep water (30–60 m) the sediments are clays or fine silts and generally have high contents of organic matter (3.0–10.8%), nitrogen (0.1–0.34%) and phosphorus (0.05–0.10%). Shallow water sediments are relatively well sorted because of resuspension of fine material, which is transported to deeper water. Here the sorting becomes poor because relatively coarser material is supplied during exceptional storm events. Discrimination on erosion/transport bottoms and on depositional bottoms was based on resuspension calculations, grain‐size parameters and Passegas (1964) CM diagrams. The IG/N ratio was an useful additional tool. From the sediment content of CaCO3 it is suggested that recent sedimentation in the deeper parts of southern Kattegat is less influenced by contributions from the North Sea than it was during the early Holocene.
Recent benthic foraminifera in the southern Kattegat, Scandinavia: distributional pattern and controlling parameters
Authors: CONRADSEN KELD
Published: July 2010

The southern Kattegat is characterized by a strong halocline at a water depth of 10–20 m. Samples were collected within and below the halocline at 12–58 m. A Q‐mode factor analysis identified three major and three minor foraminiferal assemblages, each characterized by one diagnostic species. Linear regression analyses showed that the distribution of assemblages and their diagnostic species is associated with substrate and hydrography. The Bulimina marginata assemblage is connected with fine‐grained, organic‐rich sediments below the halocline. The Elphidium excavalum and the Eggerelloides scabrus assemblages show weak correlations with substrate and are presumably connected with the halocline. Minor assemblages of Cibicides lobatulus and Textularia bocki are associated with coarse‐grained sediments. The Stainforthia fusiformis assemblage has only weak correlation with substrate and hydrography.
Coastal peats from northwest Ireland: implications for late‐Holocene relative sea‐level change and shoreline evolution
Authors: SHAW JOHN , CARTER RICHARD W. G.
Published: July 2010

Peat and organic rich sediments at coastal sites in extreme northwest Ireland have accumulated in a wide variety of environments, often strongly influenced by late Holocene changes in relative sea level and by geomorphic processes. A deep peat sequence on the coast of Aranmore Island accumulated initially in a lake and subsequently in a freshwater marsh environment. The long pollen record serves as a template for regional events. It extends over much of the Holocene and shows relatively high levels of Pinus pollen up to just before the disappearance of this taxon at c. 3600 BP. Coastal peat occurrences elsewhere are much thinner and have accumulated over shorter periods; they contain further evidence to show that coastal areas were well‐wooded compared with today, and that Pinus was an important woodland component prior to c. 4000 BP. At sites in Gweebarra Bay intertidal peats record the closure of small estuaries by geomorphological events during the past 5000 years. Coastal sites at Ballyness, Clonmass, and Trawenagh display regressive stratigraphies ˜ minerogenic marine sediments are overlain by silty peats capped by highly organic freshwater peats. Basal radiocarbon dates range from 4500 to 3300 BP. The silty peats are interpreted as having formed in salt‐marsh environments and contain distinctive pollen spectra, marked by high levels of Pinus and Compositae Liguliflorae pollen. The data suggest that relative sea level attained levels close to that of today by the mid‐Holocene in this region. The pattern of relative sea‐level change agrees well with that predicted by geophysical modelling.
Aeolian stratigraphy and thermoluminescence dating of sediments of late Holocene age from Sola, southwest Norway
Authors: SELSING LOTTE , MEJDAHL VAGN
Published: July 2010

Thermoluminescence age determinations were performed on four aeolian sand samples of late Holocene scenceagesediments from Stavanger airport, Sola, in southwest Norway. The locality is well suited for testing thermoluminescence dating because of a good agreement between radiocarbon ages and age information based on archaeological typology and sea level changes. The conclusion from a comparison of thermoluminescence and archaeologicaltypologyradiocarbon dates is that it is possible to date well bleached sediments as young as 1600 years with thermoluminescence (TL). The TL dates for the aeolian deposits are in accord with expected ages. Six formal, diachronous aeolian/non‐aeolian phases are defined and grouped together as the Sola Episode. The first phase onousaeolian/non‐aeolianof aeolian activity was short‐lasting and took place in the middle Subboreal chronozone. A second and lianactivitywaslong‐lasting period, dominated by aeolian activity, took place from the transition between the Subboreal and Subatlantic chronozones until the present. We conclude that human activities were the releasing factor for the aeolian activity recorded in sand sheets.
A lacustrine record of late Pleistocene climatic change in the subtropical Andes
Authors: SELTZER GEOFFREY O.
Published: July 2010

Significant changes in moisture have occurred in the subtropical Andes over the last 20,000 years as evidenced by shorelines of high lake stands and extensive glacial moraines. Lakes with sediment records that reflect these moisture changes are present in some valleys where headwalls are below the snowline elevation reached during the latest Pleistocene glacial culmination (14,000–12,000 BP). One such lake, Laguna Kollpa Kkota, which is located on the western slope of the eastern cordillera in Bolivia, has basal radiocarbon dates of about 20,000 BP. The snowline reconstruction for this site confirms earlier work in the region that suggests late Pleistocene snowline depression was less than 500 m, or half the amount generally considered for low‐latitude regions during the last glacial maximum. The sediment stratigraphy from Laguna Kollpa Kkota indicates that sediment accumulation and organic carbon deposition increased significantly from 14,000 to 12,600 BP. This increase in sedimentation may have resulted from greater inwash to the lake and higher productivity In the lake itself as a result of higher lake levels. These changes could reflect the postulated late Pleistocene increase in precipitation that led to the formation of Lago Tauca on the Altiplano and to glacial advances in the surrounding cordillera.
Quaternary marine stratigraphy and geochronology in central West Greenland
Authors: BENNIKE OLE , HANSEN KAREN BILLE , KNUDSEN KAREN LUISE , PENNEY DAVID N. , RASMUSSEN KAARE LUND
Published: July 2010

A new stratigraphic framework is proposed for the Quaternary of a portion of central West Greenland, based primarily on faunal and geochronologic studies of shallow shelf deposits. Twenty‐four occurrences of pre‐Holocene deposits were already known in West Greenland and data from 18 new sites are presented, together with new information on some of the previously described localities. Four pre‐Holocene marine events are described. The interglacial Ivnaarssuit and Nordre Laksebugt marine events are considered to be Middle Pleistocene in age. The interstadial Laksebugt marine event is considered to be late Middle Pleistocene, whereas the Svartenhuk marine event is correlated with the last interglacial. For the last glacial period an extensive ice shelf is proposed west of Disko. The oldest postglacial deposits are dated at 10,470 ± 13014C‐years BP.
The last glacial cycles in East Greenland, an overview
Authors: FUNDER SVEND , HJORT CHRISTIAN , LANDVIK JON Y.
Published: July 2010

Marine, fluvial and glacigene sediments exposed in coastal cliffs and stream‐cut sections in East Greenland between latitudes 69° and 78° N display a record of Quaternary climatic and environmental change going back to pre‐Saalian times (> 240 ka), but with main emphasis on the last interglacial/glacial cycle. The stratigraphical scheme is based on studies on the Jameson Land peninsula, and contains five glacial stages and stades with the Greenland ice sheet or its outlets reaching the outer coasts. Individual sites are correlated and dated by a combination of biostratigraphy, luminescence dating, amino acid analyses, as well as14C‐ and uranium series dating. The pre‐Weichselian Lollandselv and Scoresby Sund glaciations were the most extensive. During the Weichselian the Inland Ice margin in this part of East Greenland was apparently very stable. The Aucellaelv, Jyllandselv and Flakkerhuk stades mark the advance and subsequent retreat of outlet glaciers from the Inland Ice which advanced through the wide Scoresby Sund basin and reached the inner shelf. In‐between the glacier advances, three interglacial or interstadial periods have been recognized. During the Langelandselv interglacia‐tion (≅ Eemian) the advection of warm Atlantic water was higher than during the Holocene, and the terrestrial flora and insect faunas show that summer temperatures were 3–4°C higher than during the Holocene optimum. There is no unambiguous evidence for cooling in the sediments from this interval. Later, in isotope stage 5, there were apparently two ice‐free periods. During the Hugin Sø interstade, stable Polar water dominated Scoresby Sund, and the terrestrial flora suggests summer temperatures 2° ‐3° lower than the present. The marine and fluvial sediments from the second ice‐free period, the Mønselv interstade, are devoid of organic remains.
Glacial history of interior Jameson Land, East Greenland
Authors: MöLLER PER , HJORT CHRISTIAN , ADRIELSSON LENA , SALVIGSEN OTTO
Published: July 2010

The plateaus between 400 and 800 m a.s.l. around the water‐divides on central and eastern Janieson Land are covered by the ‘Jameson Land Drift’ up to 50 m thick glacial. placiotluvial and glaciolacustrine deposits. A high content of far‐travelled wcsterii rocks indicates the overriding by extensive glaciers channelled from the west through the Scoresby Sund basin. The Jameson Land Drift deposits have bccn lithostratigraphically divided into two groups. each representing the sedimentary successions from one glaciation in the wider sense of the word. sediments from the lowerLollandselv glaciationare upwards delimited by a distinct periglacial surface. TL‐dates suggest a prc‐Saalian (approximately isotope stages 11–9) age. The followingScoreshby Sund glaciation. when most of the studied Jameson Land Drift sediments were laid down. is of Saalian age (e. isotope stages 8 6). The deposits from the Scoresby Sund glaciation are interpreted as representing a complete glaciation deglaciation succession, including proglacial sandur and glaciolacustrine sediments. followed by till deposition, with an overlying succession of glaciolacustrinc and glaciofluvial sediments. From 200–250 m toc. 400 m a.s.l. there is a driftless area, exposing Jurassic sandstones, probably a result of intensive and long‐lasting periglacial erosion. Extensive occurrences of tors and of glaciofluvially (subglacially as well as subaerially) eroded canyons and channels characterize the landscape. A similar. although less well defined. upper driftless zone is found abovec500 m a.s.l. on northern Jameson Land, north of the drift‐covered plateaus. During the Wcichsclian (isotope stages 5d 2). thick glacial. fluvial and marine deposits were laid down in a coastal zone belowc. 200 m a.s.l., and only cold‐based local ice caps seem to have existed on the interior plateaus of Jameson Land. The now driftless areas were characterized by periglacial erosion during this period.
Eemian‐Weichselian stratigraphy of the Flakkerhuk ridge, southern Jameson Land, East Greenland
Authors: TVERANGER JAN , HOUMARK‐NIELSEN MICHAEL , LØVBERG KIT , MANGERUD JAN
Published: July 2010

The coast‐parallel Flakkerhuk ridge on southern Jameson Land revealed a succession of four marine formations separated by tills and glaciotectonic deformation zones representing glacier advances. Paleontological evidence. supported by 32 luminescence datings, indicates that deposition took place during the Eemian and Early Weichselian. A pronounced rise in sea‐level due to glacio‐isostatic depression is evidenced within the Late Eemian part of the sequence, indicating buildup of ice commencing while interglacial conditions still prevailed. A diamicton interpreted as a till deposited by a glacier moving from the interior of Jameson Land and overlying the interglacial deposits would seem to suggest the presence of a local ice cap on Jameson Land at the last interglacial/glacial transition. Three ice advances from the fjord onto the coast were identified following the last interglacial. The glaciers at no time advanced beyond 2–3 km inland from the coast in the investigated area. This demonstrates that the glaciers advancing through the Scoresby Sund fjord during the Weichselian were relatively thin, with a low longitudinal gradient. Glacier advances onto the coast were apparently strongly influenced by local topography and relative sea‐level. The Flakkerhuk ridge is mainly an erosional landform originating from continued fluvial downcutting of former drainage channels from along the Early Weichselian ice margin. Only the very top of the ridge is considered to he a constructional ice marginal ridge, related to the Flakkerhuk glaciation.
The Aucellaelv stade at Aucellaelv, the first Weichselian glacier advance in Scoresby Sund, East Greenland
Authors: ISRAEISON CARSTEN , FUNDER SVEND , KELLY MICHAEL
Published: July 2010

The first major Weichselian ice advance in Scoresby Sund, during the Aucellaelv stage, deposited thick till beds along the coast of Jameson Land between > 107 ka and 140 ka. and is correlated with isotope substage 5d in the marine record. This is shown by stream‐cut sections at the mouth of the Aucellaelv. Jameson Land, which contain a scquence of shallow marine, fluvial and glacigene sediments extending from the Scoresby Sund glaciation (≅Saalian) to the Flakkerhuk stade (Late Weichselian). The sequence is dated by palaeoceanographic correlation with the deep‐sea record, U/Th and luminescence dating, and correlated with the record in adjacent areas by mapping of marker horizons, and by mollusc fauna assemblages and amino acid analyses.
The lower Jyllandselv succession: evidence for three Weichselian glacier advances over coastal Jameson Land, East Greenland
Authors: LYSÅ ASTRID , LANDVIK JON Y.
Published: July 2010

Detailed investigations of sediments exposed along river sections in the coastal part of Jameson Land have revealed a Saalian to Holocene glacial history. Eleven sedimentary units have been distinguished. most of which are found in superposition at one single large section. Four subglacially formed till beds are recognized; three of which are of Weichselian age. All the tills are considered to have been deposited at the base of fjord glaciers restricted to the Scoresby Sund basin. The tills are separated by marine, fluvial or deltaic sediments, and demonstrate changes in the depositional environnient considered to represent changes in relative sea level during the ice‐free periods. The fossil content. supported by a series of luminescence dates, suggest that most of the succession is of Eemian and Early Weichselian age. From the luminescence dates, a short duration of <10ka is suggested for the Early Weichselian glacial stades. Sedimentation during this period was partly controlled by glacio‐isostatic subsidence caused by net growth of the Greenland Ice Sheet. The Middle Weichselian is represented by a large hiatus. whereas the Late Weichselian is represented by a subglacial till.
Recent foraminifera in shelf sediments of the Scoresby Sund fjord, East Greenland
Authors: MADSEN HANNE BIRGIT , KNUDSEN KAREN LUISE
Published: July 2010

A study of sea‐bottom samples from shallow waters in the northern part of Scoresby Sund, off Jameson Land, East Greenland, reveals four different foraminiferal assemblages between 1.3 and 35.6 m water depth. The shallowest samples. Assemblage SA (1.3–2.2 m), contain only very few foraminifera, presumably due to the annual repeated formation of an ice foot. Assemblage SB (3.7 and 4.3 m) is characterized by the calcareous species Haynesina nivea and H. orbiculare, while the arenaceous species Spiropleclammina biformis, Reophax arctica, and Recurvoides turbinatus dominate all the faunas of Assemblage SC (9.3–25.9 m depth). The change in fauna to the succeeding Portatrochammina bipolaris ‐ Spiropleclammina biformis fauna (Assemblage SD, 29.6 and 35.6 m) presumably corresponds to the transition from the shallow Fjord water layer to the deeper and relatively more stable Polar water. Elphidiella hannai (Cushman & Grant) is recorded live for the first time in recent assemblages from the Atlantic Ocean.
Scanning electron microscopy of Pleistocene tills in Estonia
Authors: MAHANEY WILLIAM C. , KALM VOLLI
Published: July 2010

Tills from four Pleistocene glaciations were recovered from drill cores in Estonia and subjected to particle size and microtexture analyses by Scanning Electron Microscope (SEM). All tills were deposited by thick continental ice‐sheets following the transport of, at most, several hundred kilometers during four Fennoscandian glaciations. The main problem is to determine if the type and range of microtextures present on the grain surfaces are diagnostic of transport in continental ice. The frequency of occurrence of microtextures including fractures, abrasion, and relief features are used to test the ability of continental ice to damage quartz particles emplaced as till. The range of quartz dissolution and presence of coatings on grains are also used to reconstruct the paleoenvironment that existed prior to transport as well as to estimate diagenetic effects that occurred following emplacement. The available data indicate a high degree of reworking of quartz grains from one glaciation to another. While the shapes and microtextures of grains from source rocks are not known, the great range of fracture and abrasion microfeatures, and high frequency of occurrence on grains in all tills, indicate that glaciers are effective crushing agents. An increase in the prevalence of chemically etched grains from older to younger tills suggests that some grains (c. 50%) escape crushing, either because of preservation in the ice and lack of grain‐to‐grain contact, or as a result of massive reworking of weathered grains following interglaciations.
The relative influence of local, extra‐local, and regional factors on organic sedimentation in the Vällamäe kettle hole, Estonia
Authors: PUNNING JAAN‐MATI , KOFF THU , ILOMETS MATI , JOTGI JAAN
Published: July 2010

This paper examines the data obtained during a complex study of a 17 m deep peat sequence in a small glaciokarstic kettle hole mire in SE Estonia. The pollen and macrofossil analysis and the14C data were used for the spatio‐temporal reconstruction of the development of the mire, including its vegetation and microclimatic conditions during the Holocene. The comparative analysis of the data gained allows us to estimate the relative influence of various local, extra‐local, and regional natural processes on the dynamics of the ecosystems.
Contemporary terminal‐moraine ridge formation at a temperate glacier: Styggedalsbreen, Jotunheimen, southern Norway
Authors: MATTHEWS JOHN A. , McCARROLL DANNY , SHAKESBY RICHARD A.
Published: July 2010

Terminal‐moraine ridges up to 6 m high have been forming at the snout of Styggedalsbreen for two decades. Based on intermittent observations during this period, combined with a detailed study of ridge morphology, sedimentary structures and composition during the 1993 field season, a model of terminal‐moraine formation that involves the interaction of glacial and glacio‐fluvial processes at a seasonally oscillating ice margin is presented. In winter, subglacial debris is frozen‐on to the glacier sole; in summer, ice‐marginal and supraglacial streams deposit sediments on the wasting ice tongue. The ice tongue overrides an embryonic moraine ridge during a late‐winter advance and a double layer of sediment (diamicton overlain by sorted sands and gravels) is added to the moraine ridge during the subsequent ablation season. Particular ridges grow incrementally over many years and exert positive feedback by enhancing snout up‐arching during the winter advance and constraining the course of summer meltwater streams close to the ice margin. The double‐layer annual‐meltout model is related to moraine formation by the stacking of subglacial frozen‐on sediment slabs (Krüger 1993). Moraine ridges of this type have a complex origin. are not push moraines, and may be characteristic of dynamic high‐latitude and high‐altitude temperate glaciers.
Near‐shore Baltic Ice Lake deposits in Fakse Bugt, southeast Denmark
Authors: BENNIKE OLE , JENSEN JØRN BO
Published: July 2010

Shallow seismic, sedimentological and macrofossil data and AMS radiocarbon dates on terrestrial plant remains from submarine deposits in Fakse Bugt in the southwestern part of the Baltic Sea are presented. The sediments were deposited near the shore of the Baltic Ice Lake, mostly in barrier‐lagoon environments, during two highstand episodes dated to around 12.5–12.2 14C ka BP and 10.6–10.3 ka BP. Coastal sediments from the highstands indicate maximum water levels of 13–15 m and 13 m below present sea level, respectively. During the first episode Salix polaris was widespread in the land area, and during the second episode Dryas octopetala and Betula nana were the most common woody plants. During the lowstand episode Betula pubescens woods dominated. The flora and fauna of the Baltic Ice Lake were rather diverse, reflecting the long and increasing distance to the margin of the Fennoscandian Ice Sheet. Calcium‐carbonate‐rich, mesotrophic water characterized the Baltic Ice Lake in Fakse Bugt.
Holocene changes in atmospheric circulation patterns as shown by lake status changes in northern Europe
Authors: YU GE , HARRISON SANDY P.
Published: July 2010

Changes in lake status, a measure of relative water depth or lake level, have been reconstructed from geological and biological evidence for 87 sites in northern Europe. During the early Holocene. the lakes show conditions similar to or drier than present in a broad band across southern Britain, southern Scandinavia and into the eastern Baltic and wetter conditions along the west coast and in central Europe. This pattern is consistent with the effects of a glacial anticyclone over the Scandinavian Ice Sheet, namely enhanced southwesterly flow along the west coast and strengthened easterlies south of the ice. After c, 8000 BP a different lake status pattern was established. with conditions drier than present over much of northern Europe. Lakes higher than today were confined to the far north, the west coast, eastern Finland and western Russia. This pattern gradually attenuated after 4000 BP. Differences in lake status during the mid‐ to late Holocene are consistent with a strengthening of the blocking anticyclone over the Baltic Sea in summer. resulting in more meridional circulation than today. This strengthening of the blocking anticyclone during the mid‐Holocene is interpreted as a consequence of insolation changes, enhanced by the fact that the Baltic Sea was larger than present.
Degree of rock surface weathering on fjell summits in northern Finland: implications for the thermal regime of the last ice sheet
Authors: McCARROLL DANNY , AUTIO JYRKI , HEIKKINEN OLAVI , KOUTANIEMI LEO
Published: July 2010

Measures of degree of rock surface weathering on three fjell summits in Finnish Lapland provide an independent test of the extent of continuously cold‐based ice during the Late Weichselian. The surface hardness of exposed surfaces is compared with that of surfaces that have remained covered and protected from subaerial weathering. Roughness measurements from granite gneiss surfaces are compared with results from similar lithologies that are known to have been eroded during the Late Weichselian. The results suggest that the summits have been covered and actively eroded by warm‐based ice and are difficult to reconcile with suggestions that large parts of Fennoscandia have not been glacially abraded since the Early Weichselian.
Moraine ridges formed from subglacial frozen‐on sediment slabs and their differentiation from push moraines
Authors: KRÜGER JOHANNES
Published: July 2010

Throughout the 1980s the annual cycle of ice‐front activity along the stationary north margin of the ice‐cap Myrdalsjökull, southern Iceland, produced a complex ridge, 4 m high, composed of imbricately stacked slabs of frozen, clast‐paved lodgement till dipping up‐glacier. Further observations in 1994 revealed that glaciofluvial processes and associated deposits may be involved in the final stage of ridge production depending on local climate and meltwater drainage pattern. It is concluded that at the margin of Myrdalsjökull the progressive stacking of subglacial frozen‐on sediment slabs to form a moraine ridge is a fundamentally similar mechanism to that involved in the incremental double‐layer model reported from Styggesdalsbreen, southern Norway. This study has also identified internal characteristics which are of potential use for distinguishing between moraine ridges formed by this mechanism and push moraines formed by proglacial thrusting.
Deforming bed conditions on the Dánischer Wohld Peninsula, northern Germany
Authors: HART JANE K. , CANE FIONA , WATTS ROBERT J.
Published: July 2010

At the Dänischer Wohld Peninsula coastal sections (North West Germany), subglacial deformation was found at three scales. At the smallest scale, features typical of deforming bed tills were found, i.e. small boudins, tectonic laminations and low fabric strength till. At an intermediate scale, large lenses of glaciolacustrine sediments were found within subglacially deformed till. At the largest scale, there were large (over 5 m high) subglacial folds. We suggest that these styles of sedimentation/deformation were associated with a series of readvances during overall glacial retreat: subglacial deformation occurred during each advance and glaciolacus trine sedimentation occurred during each retreat. This led to glaciolacustrine sediments and deforming bed tills being folded together during subsequent readvances. Where the rheology was relatively weak, the lacustrine sediments were totally incorporated into the diamicton and lost their previous identity. However, where the glaciolacustrine sediments were relatively strong, they survived. We suggest that this style of deformation is typical of the conditions just upglacier from the ice margin and is associated with a relatively thick deforming layer and a high input of subglacial sediment. We conclude that the evidence found at this site provides further indications that the southern margins of the Fenno‐Scandinavian ice sheet were coupled with the glacier bed and underwent deforming bed conditions.
The magnetic susceptibility record in the Polish and western Ukrainian loess‐palaeosol sequences conditioned by palaeoclimate
Authors: NAWROCKI JERZY , WØJCIK ANTONI , BOGUCKI ANDRIEJ
Published: July 2010

The magnetic susceptibility of loess‐palaeosol sequences in southern Poland and western Ukraine varies mainly with the degree of decomposition of detrital magnetite grains conditioned by palaeoclimate. Relatively high susceptibility values were observed in the unweathered loess horizons and in accumulation horizons of the non‐gleyed soils which contain relatively high amounts of paramagnetic fraction and pedogenic (?) magnetite. The susceptibility curves characteristic for Polish and western Ukrainian loess‐palaeosol sequences may be directly correlated with oxygen‐isotope fluctuations in deep‐sea sediments. This correlation is more complex than that for the Chinese or Alaskan loess‐palaeosol sequences. The major causes of the complexities are the relatively small thicknesses of the investigated sections (especially their older horizons) and the heterogeneity of geochemical processes that affected loess surface in the interglacial and interstadial times.
Ice wastage and landscape evolution along the southern margin of the Laurentide Ice Sheet, north‐central Wisconsin
Authors: HAM NELSON R. , ATTIG JOHN W.
Published: July 2010

The Chippewa and Wisconsin Valley Lobes of the Laurentide Ice Sheet reached their maximum extent in north‐central Wisconsin about 20 000 years ago. Their terminal positions are marked by a broad area of hummocky topography, containing many ice‐walled‐lake plains, which is bounded on the up‐ice and down‐ice sides by ice‐contact ridges and outwash fans. The distribution of these ice‐disintegration landforms shows that a wide zone of stagnant, debris‐covered, debris‐rich ice separated from the active margins of both lobes as they wasted northward during deglaciation. Accumulation of thick, uncollapsed sediment in ice‐walled lakes high in the ice‐cored landscape indicates a period of stability. In contrast, hummocky disintegration topography indicates unstable conditions. Thus, we interpret two phases of late‐glacial landscape evolution. During the first phase, ice buried beneath thick supraglacial sediment was stable. Supraglacial lakes formed on the ice surface and some melted their way to solid ground and formed ice‐walled lakes. During the second phase, buried ice began to melt rapidly, hummocky topography formed by topographic inversion, and supraglacial and ice‐walled lakes drained. We suggest that ice wastage was controlled primarily by climatic conditions and supraglacial‐debris thickness. Late‐glacial permafrost in northern Wisconsin likely delayed wastage of buried ice until after about 13 000 years ago, when climate warmed and permafrost thawed.