bluuebunny/crossref_metadata_2025_split huggingface dataset:
The history of Erica erigena R. Ross, an Irish plant with a disjunct European distribution
Authors: Foss Peter J. , Doyle Gerard J. 
Published: February 2007

AbstractScanning electron microscopy combined with pollen, spore, rhizopod and fungal analyses of two peat profiles at Claggan Mountain, Co. Mayo, sheds new light on the Holocene history of Erica erigena in western Ireland. This heather is referred to the Mediterranean‐Atlantic group in the Irish flora, and is remarkable for its disjunct distribution in Europe, where it occurs in Ireland, Bordeaux in France, and in Spain and Portugal.Scanning electron microscopy has proved a powerful tool, allowing the unambiguous identification of ericoid pollens to species level and it is used to identify the first occurrence of Erica erigena pollen in the peat profiles. Radiocarbon dating of the profiles shows that Erica erigena is a relatively recent arrival at Claggan Mountain, appearing for the first time in the historic period at 1431 AD. The details of vegetational changes associated with the expansion of E. erigena have been explored by conventional pollen, spore, rhizopod and fungal analyses. Drying of the peat surface and replacement of bog vegetation by ericaceous heathland during a period of marked agricultural activity in the region was associated with its spread.The relatively recent arrival of E. erigena at Claggan Mountain, suggests that introduction might explain its presence here, and its disjunct distribution in Europe. Documented trade and pilgrimage routes between Ireland and those areas in Europe where the heather occurs may have allowed its recent introduction into Ireland. Further pollen analysis work, using SEM techniques, will be required if an earlier occurrence for the heather in Ireland is to be proved. The combination of techniques described here may prove useful in the study of the history of other plants with pollen that is difficult to identify using conventional light microscopy.
European vegetation history: Palaeovegetation maps from pollen data ‐ 13 000 yr BP to present
Authors: Huntley Brian 
Published: February 2007

AbstractPollen data are the most important source of information with respect to late Quaternary vegetation history. Broad‐scale palaeovegetation patterns have been subjectively inferred from mapped pollen data by previous authors. In this study, multivariate classification was applied to European pollen data for the last 13 000 yr. The resulting clusters are mapped at millennial intervals and can be equated with vegetation units. The maps portray the changing vegetation of Europe since the last glacial. They reveal the impermanence of the assemblages of species that ecologists recognise as communities. The dominant patterns in the maps also change through time, indicating important changes in palaeoenvironmental conditions and in the alignment of major environmental gradients. Human impact upon European vegetation history is seen to be relatively unimportant when the vegetation is viewed at a continental scale.
Stratigraphy and thermoluminescence dating of Late Glacial cover sand in Denmark
Authors: Kolstrup Else , Grün Rainer , Mejdahl Vagn , Packman Susan C. , Wintle Ann G. 
Published: February 2007

AbstractIn western Jutland deposits with a texture and structure similar to Dutch cover sands have been found. Investigations have been carried out on the lithology and the lithostratigraphic sequences. Pollen analysis is used for biostratigraphic correlation, and ages have been obtained by the radiocarbon method as well as by thermoluminescence techniques using both quartz and eldspar. The five sites are presented separately and the data are integrated into a general stratigraphic outline of the Late Glacial cover‐sand sequence in Jutland.During the latest part of the Upper Pleniglacial and the earliest Late Glacial, older cover‐sand type was deposited. Locally this sediment was also deposited during the later parts of the Late Glacial. Younger cover‐sand type was deposited primarily during the Early Dryas and Late Dryas, but some sand of this type was also laid down during the Allerød and the earliest Holocene. The palaeobotanical records are discontinuous, but plant growth was probably present throughout the Late Glacial; only during the Altered did the deposition of sand decrease long enough to allow a relatively stable vegetational development. The investigation shows that the sequence of events in Jutland is similar to the Dutch record.
Niveo‐aeolian sand deposition in subarctic dunes, eastern coast of Hudson Bay, Québec, Canada
Authors: Bélanger Simon , Filion Louise 
Published: February 2007

AbstractAeolian sand transport during winter and the snow‐free season was assessed quantitatively by direct year‐round field measurements along transects on the lee side of parabolic dunes in subarctic Québec. In 1987–1988, niveo‐aeolian deposition was more important than aeolian sedimentation in three of the four study sites, and contributed > 75% of the total annual accumulation in exposed sites and < 25% in protected forest sites. The maximum depth of interstratified snow and sand deposits (3.5 m) was recorded in March. Semi‐permanent snow lenses may persist longer than 2 years in the aeolian sediments. After dissipation of snow, 22 cm of sand (as a maximum) accumulated on the slipface of the most active dunes, whereas only minor sand accumulation occurred in distant areas from active sand erosion. Wind‐driven sand was dispersed over 7.4 km2 in the Whapmagoostui‐Kuujjuarapik area. The acumulation of snow and sand during the snow season, together with spring thaw and collapse of the niveo‐aeolian deposit, caused different types of injuries to trees, especially in 1985 and 1987 when a maximum of torn branches was recorded over the last 10 year period.
Glacial deposits at Wylfa Head, Anglesey, North Wales: Evidence for Late Devensian deposition in a non‐marine environment
Authors: Harris Charles 
Published: February 2007

AbstractThe nature and origin of glacial sediments at Wylfa Head are described, and their significance with regard to sedimentary environments during Late Devensian deglaciation of the Irish Sea Basin is discussed. Recent models of deglaciation under glaciomarine conditions are challenged. The Quaternary sequence at Wylfa consists of eroded and glaciotectonically deformed bedrock, locally derived lodgement till, calcareous silt‐rich lodgement till containing northern erratics, discontinuous units of orange‐brown silty sand of possible aeolian origin, and grey laminated freshwater silts filling a small kettle hole. The till units thicken to the south where the surface is drumlinised. It is concluded that the landforms and deposits result from a warm‐based Irish Sea glacier, which moved towards the southwest. Spatial variation in basal water pressure resulted from localised drainage through zones of more heavily jointed bedrock. Rapid glacial erosion occurred in areas where subglacial water pressure was relatively high, while deposition of the resulting basal sediment took place where water pressures were reduced. The glacier also carried basal calcareous silty till onshore, which was deposited by lodgement processes. None of the deposits at Wylfa are interpreted as glaciomarine in origin, and there is no evidence at this site for an isostatically induced marine transgression prior to deglaciation.
The Late Quaternary vegetational and climatic history of Easter Island
Authors: Flenley J. R. , King A. Sarah M. , Jackson Joan , Chew C. , Teller J. T. , Prentice M. E. 
Published: February 2007

AbstractEaster Island occupies an exceptionally isolated position in the south Pacific Ocean. It is entirely volcanic, and is famous for its giant statues. Late Quaternary sediments have been investigated in three craters: Rano Raraku, Rano Aroi and Rano Kao, giving a continuous record over the past 30 Ka. Pollen records indicate that the island was formerly forested. Palynological and sedimentological evidence suggests a Late Pleistocene climate slightly cooler and drier than the present. Deforestation by people occurred mainly between 1200 and 800 yr BP. This may have led to an ecological disaster and to the decline of the megalithic civilization. The depauperation of the present native flora owes more to human activity than to isolation.
Formation of De Geer moraines and implications for deglaciation dynamics
Authors: Larsen Eiliv , Longva Oddvar , Follestad Bjørn A. 
Published: February 2007

AbstractDe Geer moraines are very common in the Møre area, western Norway. These moraines occur below the marine limit and outside the Younger Dryas ice limit and occupy tributaries that connect the main fjords through the mountain passes. During deglaciation, ice in these tributaries flowed to the major ice streams.Sections across three De Geer moraines show that the ridges are composed of diamictons and fine‐grained sediment, partly in stacked sequences. The diamicton units are interpreted as being composed of water‐lain tills, lodgements tills and subaqueous flow deposits. The fine‐grained sediment is though to have formed in a proglacial marine environment. Clast fabric of diamictons and deformation structures in underlying sands show that depositional directions for diamicton units and the direction of deformation for the sands is perpendicular to the ridge crests. Mainly based on this evidence, the ridges are thought to have formed by push at the glacier grounding line. The formation of transverse ridges (relative to ice flow) do occur in basal crevasses on modern glaciers, as do swarms of ridges along the front of retreating glaciers. The first mechanism of deposition does not seem to explain the ridges studied in the present paper and hence the importance of this process in the formation of De Geer moraines is questioned.The De Geer moraines were deposited by ice lobes advancing from one main fjord into another; therefore by studying the drainage pattern of the tributary lobes and their sequence of deglaciation, many features of the style of deglaciation of the ice sheet across the area can be determined.The northwestern part of the area was deglaciated earliest. After that, deglaciation proceeded to the southwest parallel to the coast. Subsequently the outer and the central part of Romsdalsfjorden were deglaciated causing ice to drain towards this fjord from both the north and south. The last fjord to be deglaciated was Storfjorden in the south.
The extension of the Late Weichselian/Late Devensian ice sheets in the North Sea Basin
Authors: Ehlers Jürgen , Wingfield Robin 
Published: February 2007

AbstractThe distribution of large channel‐like features, comprising Weichselian/Devensian incisions, in the western North Sea provides evidence for a much larger extension of the last ice sheet than currently assumed. Morphological comparison of the incisions with those in North Germany and Poland reveals a striking similarity in shape and distribution. The features on the North Sea floor are interpreted as being formed by meltwater erosion within the margin of the ice sheet. The widespread absence of Weichselian/Devensian till in the area under consideration may be attributed to later erosion. Large‐scale reworking and redistribution of sediments is indicated by the complete sediment infill of the majority of the incisions.
Glacier response to climatic change during the Loch Lomond Stadial and early Flandrian: Geomorphological and palynological evidence from the Isle of Skye, Scotland
Authors: Benn Douglas I. , Lowe J. John , Walker Michael J. C. 
Published: February 2007

AbstractThe deglaciation of Skye at the close of the Loch Lomond Stadial is assessed on the basis of detailed geomorphological mapping and pollen‐stratigraphic correlations. It is concluded that deglaciation proceeded in two distinct stages. The first was marked by numerous glacier stillstands and readvances, while uninterrupted retreat and local glacier stagnation occurred during the second and final stage. The pollen evidence indicates that the first stage was well advanced before the marked thermal improvement at the start of the Flandrian, and it is inferred that initial glacier retreat occurred in response to a decline in precipitation in the later part of the Loch Lomond Stadial. The first stage of glacier retreat continued into the early Flandrian, during which climatic amelioration was interrupted briefly. Final deglaciation appears to have occurred rapidly in response to sustained temperature increases. The collective evidence also indicates spatial variations in the timing of deglaciation, which appear to reflect differences in glacier morphology.
Mineral magnetic analyses as a means of lithostratigraphic correlation and provenance indication of glacial diamicts: Intra‐ and interunit variation
Authors: Walden John , Smith John P. , Dackombe Roger V. 
Published: February 2007

AbstractMineral magnetic analyses are applied to a series of diamict samples taken from the Quaternary sequence in the Isle of Man in order to assess the relative magnitude of the intra‐and inter‐unit variation of the magnetic properties. The results are analysed both qualitatively and quantitatively and show that the level of intra‐unit variation is significantly less than the level of inter‐unit variation. The intra‐unit variation detected appears to show some relationship to the basic stratigraphy. Previous correlations based upon field evidence of diamict units exposed upon the east and west coasts of the Isle of Man are supported by their mineral magnetic properties. The statistically significant differences in the magnetic mineralogy of the stratigraphically lower Wyllin and Shellag Tills and the upper Orrisdale, Ballavarkish and Ballaquark Tills suggests distinct provenances for these two suites of sediments, allowing potential source areas to be suggested. These source areas are consistent with published data on ice flow directions in the Irish Sea Basin during the Devensian.
Foraminifera from the Irish Sea glacigenic deposits at Aberdaron, western Lleyn, North Wales: Palaeoenvironmental implications
Authors: Austin William E. N. , McCarroll Danny 
Published: February 2007

AbstractIn a sequence of glacigenic sediments at Aberdaron, Foraminifera were obtained from samples located specifically in order to differentiate between opposing models of depositional environment. All the diamict samples yielded remarkably uniform assemblages, with similar numbers of benthic specimens and benthic species per unit weight of sediment, similar planktic : benthic ratios, and similar ratios of clearly allochthonous to possibly autochthonous elements. This is precisely as predicted by the terrestrial model of sedimentation, where all of the sediments are interpreted as being derived from the melting of glacier ice rich in marine debris entrained during passage along the Irish Sea Basin. The results lend no support to a glacial marine model, since no faunal responses to increasingly distal sedimentary environments are observed. However, the fauna is dominated by the Foraminifera Elphidium excavatum (Terquem) forma clavata Cushman, which is commonly assumed to indicate glacial marine conditions. The modern distribution of similar assemblages suggests that it is just as likely to represent the cold, reduced salinity conditions that would have prevailed in the northern Irish Sea Basin for much of the Quaternary.
The magnetic properties of Quaternary and Tertiary sediments in the southern North Sea
Authors: Thompson R. , Cameron T. D. J. , Schwarz C. , Jensen K. A. , Maenhaut Lemberge V. Van , Sha L. P. 
Published: February 2007

AbstractCores from boreholes penetrating late Quaternary, glacial, interglacial and postglacial sediments and the underlying late Cenozoic delta complex of the southern North Sea have been examined for their magnetic properties. A magnetic polarity stratigraphy has been established as an aid to biostratigraphic dating of the sediments; the Kaena‐Gauss and Gauss—Matuyama transitions and the base and top of the Olduvai subchron have been identified. The strength and stability of laboratory‐induced isothermal remanent magnetisation display clear magneto‐petrological variations, which match lithostratigraphic changes in the cores. Principal component analysis has picked out a basin‐wide and palaeoenvironmental consistency in the magnetic data. Large, multi‐domain magnetite grains predominate in the post‐deltaic and fluvio‐deltaic sediments, whereas smaller greigite or titanomagnetite grains are concentrated in the intertidal and marine deltaic facies. Since heavy mineral analysis indicates that most of the deltaic detritus derived from common source areas, the differences in magnetic mineralogy have probably been caused by the sediment transport processes operating within the delta complex.
Periglacial microjointing and faulting in Weichselian fluvio‐aeolian deposits
Authors: Mol Joanne , Vandenberghe Jef , Kasse Kees , Stel Harry 
Published: February 2007

AbstractA Weichselian Late Pleniglacial fluvio‐aeolian deposit has been investigated in the southern Netherlands. Three main structural lineaments have been distinguished: (1) very small, vertical platy structures (microjoints), in a parallel and a columnar configuration; (2) large joints and normal faults with minor displacement (‘Grubbenvorst type’), arranged in a conjugate fault‐system; (3) large joints and normal faults (‘wedge‐type’), located adjacent to ice‐wedge casts.Since clay is absent, the occurrence of the vertical platy structures cannot be attributed to desiccation cracking. The vertical platy structures are interpreted as the result of thermal contraction cracking of a relatively thin layer, due to a sudden temperature drop.The large joints and normal faults of the Grubbenvorst type are the result of failure of the sediment due to the melting of the permafrost in the Late Pleniglacial, just before the formation of the Beuningen Gravel Bed. In other areas large periglacial convolutions have been formed during the same period. The normal faults and joints of the wedge type are more generally known. They are the result of failure of the sediment adjacent to a melting ice wedge.
The distinction between postcranial bones of Bos primigenius Bojanus, 1827 and Bison priscus Bojanus, 1827 from the British pleistocene and the taxonomic status of Bos and Bison
Authors: Gee Henry 
Published: February 2007

AbstractThe study of British Pleistocene mammal faunas has been hampered by the difficulty of telling the difference between the postcranial elements of the often abundant remains of the large bovids Bos primigenius Bojanus, 1827 and Bison priscus Bojanus, 1827. Here I present qualitative and morphometric criteria whereby Bos primigenius and Bison priscus radii, metacarpals, tibiae, astragali and metatarsals can be told apart using British Pleistocene material.
Land snails from the last glacial maximum on Andikithira, southern Greece and their palaeoclimatic implications
Authors: Gittenberger Edmund , Goodfriend Glenn A. 
Published: February 2007

AbstractAn assemblage of land snails from an aeolianite deposit on the coast of the southern Greek island of Andikithira is shown to date to 16 000 yr BP and thus represents the period of the last glacial maximum (LGM; Oxygen Isotope Stage 2). The assemblage has no modern analogue. Five of the ten species are extinct on the island and some of these now live only at high elevations (> 950 m). Significantly cooler temperatures, some 5‐8°C below present, and slightly drier moisture conditions (lower rainfall, partially offset by reduced evapotranspiration at the lower temperature) are inferred. The large temperature depression at the LGM, well documented in northern and central Europe, extended also to the Mediterranean climate of southern Europe. Late Quaternary climatic changes had a considerable impact on the fauna of this isolated island.
Till in the marine environment
Authors: King Lewis H. 
Published: February 2007

AbstractTill is of common occurrence in the marine environment and can be both subglacial and proglacial in origin. Former glacial margins are often represented by till tongues, that are interbedded with stratified glaciomarine sediment, and the relationship is readily mappable using seismic reflection techniques. It is inferred that within individual till tongues, sediment‐gravity flow deposits form transitional contacts with till of subglacial origin, but these contacts cannot be distinguished on seismic profiles. These unstratified, gravity‐induced deposits formed in close proximity to the glacial source at the grounding line are considered to be secondary tills (flow‐till complex) in terms of the INQUA classification of tills.Till‐tongue successions and till deltas are large, ice‐marginal depocentres associated with floating front ice‐margins, and appear to be closely related in origin.Tabular and hummocky moraines of the mid‐Norwegian Shelf also are considered to be products of floating‐front margins and represent a large proportion of the retreat tills formed during ice recession.Seismostratigraphic evidence for channelisation in ice‐marginal deposits appears to provide a means of distinguishing between former tidewater and floating‐front margins.
A high‐resolution record of Lateglacial and early Holocene marine sediments from southwestern Sweden; with special emphasis on environmental changes close to the Pleistocene‐Holocene transition and the influence of fresh water from the Baltic basin
Authors: Bergsten Helene 
Published: February 2007

AbstractA high‐resolution study of a marine depositional record (43 m long), dated by accelerator mass spectrometry, from Göteborg (Gothenburg), southwestern Sweden, shows biostratigraphical and sedimentological changes of environmental significance during the Lateglacial and early Holocene. High accumulation rates are recorded from the onset of the deglaciation of the area, ca. 13 500 yr BP, until 10 300 yr BP, by which time approximately 100 m of marine sediments were deposited. The early Holocene is represented by 10 m only of sediment.The influence on the Skagerrak‐Kattegat coastal area of the dramatic, final drainage of the Baltic Ice Lake, at 10 300 yr BP, is re‐evaluated. Its impact on the distal Swedish west coast was limited and sediments that were previously related to this drainage are reinterpreted. Here, it is suggested they reflect resuspension and redeposition of sediments from the large inland Lake Vänern basin between ca. 9500 and 9000 yr BP. At 10 200 yr BP a general climatic change and a sudden incursion of warm and saline Atlantic water into the Norwegian Sea occurred and the Skagerrak altered environmental conditions, with more temperate bottom‐water conditions in the investigation area.
Late Quaternary evolution of Lake Urana, New South Wales, Australia
Authors: Page Kenneth , Dare‐Edwards Anthony , Nanson Gerald , Price David 
Published: February 2007

AbstractLake Urana is a well‐preserved relict lake in the semi‐arid Riverine Plain of southeastern Australia. A compound lunette at its eastern shoreline consists of a quartz‐sand‐dominated unit (Bimbadeen Formation), thermoluminescence (TL) dated at 30 ka to 12 ka, and a clay and sand facies unit (Coonong Formation), dated at 55 ka to 35 ka. The intervening period indicates a phase of periodically exposed lake floor and soil formation. The older wet phase conforms well with similar environments recorded from the same period at Lake Mungo. However, the return to high water levels from 30 ka to 12 ka departs sharply from the generally accepted palaeoclimatic model from Australia, which demands severe glacial maximum desiccation and widespread construction of clay lunettes. Although hydrological budgets calculated for Lake Urana and nearby Lake Cullivel require high glacial maximum water levels they do not support higher precipitation.