bluuebunny/crossref_metadata_2025 huggingface dataset:
Der Bodenwasserhaushalt an einem Fichtenstandort im Hochschwarzwald – Messung und Modellierung zur Deutung der montanen Nadelvergilbung
Authors: Zimmermann Lothar , Feger Karl‐Heinz
Published: February 2007

Das Auftreten der montanen Nadelvergilbung bei Fichte wurde wiederholt mit Trockenjahren in Zusammenhang gebracht und als Folge mangelnder Magnesiumernährung erklärt. Zur Überprüfung dieser Erklärungsmöglichkeit wurde der Bodenwasserhaushalt des Hochlagenstandortes Schluchsee (Südschwarzwald) analysiert. Aufgrund der klimatischen Situation, der bodenphysikalischen Eigenschaften und der Durchwurzelung war ein direkter Trockenstreß für den Fichtenbestand nicht zu erwarten. Um die zeitliche Dynamik und vertikale Verteilung der Bodenfeuchte in Einzeljahren verfolgen zu können, wurde ein Bodenwasserhaushaltsmodell mit den Bodenwassermessungen einer 8jährigen Meßperiode (1987–1995) angepaßt. Das Modell ermöglicht die retrospektive Simulation des täglichen Bodenwasserhaushaltes mit Klimadaten von umliegenden Wetterstationen bis 25 Jahre vor Meßbeginn. In den meisten Jahren von 1962 bis 1986 herrschten feuchte Bodenverhältnisse. In den Trockenjahren 1976 und 1983 kam es dagegen in der organischen Auflage zu einer Austrocknung bis zum permanenten Welkepunkt. Im Unterschied zu den trockenen Meßjahren 1991 und 1992 lag der Zeitpunkt der Trockenphase 1976 und 1983 bereits kurz nach Beginn der Vegetationsperiode. Im Jahr 1983 hielt die Austrocknung der organischen Auflage außerdem über 6 Wochen an. Im Frühsommer bei hohem Nährstoffbedarf des Bestandes kann es wegen der Flachwurzeligkeit der Fichte zu trockenheitsbedingten Engpässen in der Nährelementversorgung kommen. Dies betrifft am Standort besonders Magnesium, das sich latent im Mangel befindet und vorwiegend durch die Streuzersetzung nachgeliefert wird. Im Mg‐armen Mineralboden werden normalerweise keine deutlich transpirationslimitierenden Matrixpotentiale erreicht, so daß die Wasserversorgung auch in Trockenperioden gewährleistet ist. Das Auftreten der montanen Nadelvergilbung scheint somit an das Witterungsextrem frühsommerliche Trockenheit und dadurch induzierte Ernährungsstörungen gekoppelt zu sein.
Die Bestimmung der effektiven Kationenaustauschkapazität von Gesteinen
Authors: Deutschmann Gerd , Rummenhohl Holger , Tarrah Jamal
Published: February 2007

Aus jeweils einer unbehandelten, zermörserten und gemahlenen Sandstein‐, Tonschiefer‐, Diabas‐ und Alkali‐Olivinbasalt‐Gesteinsprobe wurden Kationen mittels 1 N NH4Cl in Batch‐ und Perkolationsverfahren extrahiert. Diese Verfahren wurden mittels Rücktauschversuchen bewertet. Zusätzlich wurden die Mineralzusammensetzung und die Porosität der Gesteine untersucht sowie deren spezifische Oberfläche gemessen.

In den Gesteinen wurden zum Kationenaustausch befähigte Alumosilikate (z.B. Illite, Zeolithe) gefunden. Bei dem porenarmen Tonschiefer und Basalt erhöht sich die spez. Oberfläche durch Zermörsern und Mahlen, ebenso die Austauschkapazität, z.B. Tonschiefer von 27 auf ≈ 40 μmolc g−1. Dies gilt nicht für den porösen Diabas und Sandstein, für die angenommen wird, daß bei der Extraktion von Gesteinsbruchstücken auch innere Bereiche erfaßt werden.

Die Kationenaustauschkapazität macht 50–80% der Summe der durch NH4Cl extrahierbaren Kationen aus. Die Differenz wird als Resultat der Lösung von Salzen angesehen. Durch Zermörsern und Mahlen der Gesteine steigt die Menge löslicher Kationen an.

Insgesamt zeigen diese Versuche, daß das Gestein nicht nur im Hinblick auf die Silikatverwitterung, sondern auch als Kationenaustauscher zu berücksichtigen ist.
Microbial biomass and N mineralization in relation to N supply of sugar beet under reduced tillage
Authors: Hoffmann Christa , Platte Heidrun , Lickfett Thomas , Koch Heinz‐Josef
Published: February 2007

Reduced tillage may affect N supply of plants by influencing soil microbial biomass and thereby N release. The aim of this study was to evaluate changes in microbial biomass due to tillage in relation to N mineralization and to assess the contribution to the N supply of sugar beet. For this purpose, in a field trial near Göttingen in 1995 microbial biomass and net N mineralization were determined in an in situ incubation of ploughed and reduced tilled soil in plots which were not given application of mineral N fertilizer.

In reduced tilled soil the increase in mineral N concentration in the upper 10 cm of soil was mainly attributed to an increase in microbial biomass. The organic matter was more easily decomposable, indicated by the increase in Cmic/Corg and Nmic/Nt ratios; this was further supported by the enhanced turnover of microbial biomass in reduced tillage plots. A regression function was used to relate seasonal fluctuations of microbial biomass, soil moisture and soil temperature to N mineralization rate. There was a good agreement between measured and calculated N mineralization rate. Reduced tillage affected N mineralization by affecting the quantity and quality of microbial biomass. In 0–30 cm soil depth 169 kg N/ha were mineralized, 30 kg more N than in ploughed soil. However, despite improved N availability, the N uptake of sugar beet was decreased in reduced tilled soil. Because the N concentration in plants did not differ, it was concluded that sugar beet growth in reduced tilled soil was impaired due to other factors than N supply.
Physiological and Biochemical Processes Related to Ammonium Toxicity in Higher Plants
Authors: Gerendás Jóska , Zhu Zhujun , Bendixen Roy , Ratcliffe R. George , Sattelmacher Burkhard
Published: February 2007

Nitrate and ammonium have different effects on many biochemical and physiological processes in plants, and at high concentrations this can lead to markedly different growth responses. Most plant species show reduced growth, smaller leaves and a stunted root system when exposed to high ammonium concentrations, and in severe cases this leads to chlorosis. Although well known, ammonium toxicity is poorly understood and is generally considered to be the result of one or more of the following effects; (i) ammonium‐induced mineral nutrient deficiency, arising from the impaired uptake of metal ions; (ii) secondary growth inhibition arising from the acidification of the rooting medium; (iii) alterations in intracellular pH and osmotic balance; (iv) uncoupling of photophosphorylation from electron transport, following the accumulation of ammonium in leaves; and (v) altered polyamine and phytohormone metabolism.

These hypotheses are reviewed in the light of the available literature and experimental evidence from own experiments. It is concluded that no mechanism on its own provides an adequate explanation of the available data.
Mycorrhizal colonization and lead distribution in root tissues of Norway spruce seedlings
Authors: Jentschke Georg , Fritz Eberhard , Marschner Petra , Rapp Christine , Wolters Volkmar , Godbold Douglas L.
Published: February 2007

Non‐inoculated spruce seedlings (Picea abies Karst.) and spruce seedlings colonized with Lactarius rufus Fr., Pisolithus tinctorius Coker & Couch or Paxillus involutus Fr. were grown for 35 or 37 weeks in a microcosm system on two types of natural forest humus differing in Pb content. Using X‐ray microanalysis, the distribution and content of Pb in the tissues of mycorrhizal and non‐mycorrhizal root tips were compared. No significant difference in the Pb contents of root cortex cell walls of non‐mycorrhizal and seedlings colonized by Lactarius rufus, Pisolithus tinctorius, or indigenous mycorrhizal fungi (mainly Tylospora sp.) was found. However, in root tips of seedlings colonized by Paxillus involutus, due to a higher binding capacity for cations, the Pb content in cell walls of the root cortex were higher than in non‐mycorrhizal roots. Pb contents in cell walls of the cortex of mycorrhizal and non‐mycorrhizal roots were 3 times higher in plants growing in humus with a high Pb content than in plants growing in humus with a low Pb content. It is concluded that increasing contents of Pb in the organic matter may lead to an increased loading of the apoplast with Pb. The mycobionts tested in this investigation did not exclude Pb from root tissues.
Veränderungen physikalischer Bodenmerkmale im „Statischen Düngungsversuch”︁ während einer Vegetationsperiode
Authors: Leinweber Peter , Kahle Petra , Körschens Martin
Published: February 2007

Ziel dieser Untersuchung war es, kurzfristige Veränderungen physikalischer Bodenmerkmale in unterschiedlich gedüngter Löß‐Schwarzerde zu erfassen. Dazu wurden aus Parzellen mit 17,2 g Corg kg−1 (ungedüngt) und 25,0 gorg kg−1 (NPK + Stallmist) des „Statischen Düngungsversuches”︁, Bad Lauchstädt, wöchentlich Proben entnommen und auf Wassergehalte (θ), Trockenroh‐ (ϱd) und Festsubstanzdichten ( d) sowie organische Bodensubstanzen untersucht. Die Wassergehalte verliefen in beiden Düngungsvarianten sehr ähnlich und unterschieden sich mit ≈ 16 Vol.‐% (ungedüngt) bzw. ≈ 10 Vol.‐% (NPK + Stallmist) nur im Sommer deutlich (Mittelwert aus 25.–29. Woche). Die ϱd‐Werte zeigten geringere Dichten in der NPK + Stallmist‐Parzelle (x̄ = −0,10 g cm−3) und in beiden Varianten gleichgerichtete Veränderungen, die mit Gehalten und Merkmalen der organischen Bodensubstanzen (Corg, Nt, C/N) korrelierten. Diese Daten gaben aber keine Hinweise auf die Ursachen kurzfristiger Veränderungen der ϱs um bis zu 0,09 g cm−3.
Influence of Humic Acid on Water Adsorption Characteristics of Kaolin and Quartz
Authors: Sokolowska Zofia , Hajnos Mieczyslaw , Jozefaciuk Grzegorz , Hoffmann Christian , Renger Manfred
Published: February 2007

Water vapor adsorption isotherms were measured for samples of kaolin and quartz amended with different amounts of humic acid extracted from a Cambic Arenosol under forest. Applying the approximation of the adsorption isotherms with the BET equation the monolayer capacities (surface areas) for the studied systems were calculated. For kaolin systems the surface area decreased sharply at low humic acid additions and this slowly increased with the further rise of the humic acid content, whereas for the quartz the increase of surface area was only noted for high humic acid contents. Using an exponential isotherm equation with a local BET model, the adsorption energy distribution functions were calculated for kaolin systems. The shape of the adsorption energy distributions showed that the increase in humic acid content changed the character of the surface from more hydrophilic to more hydrophobic. For intermediate humic acid contents, the energy distribution function had two maxima – more polar and less polar. At high humic acid contents the energy distribution function tended to the estimated value for pure humic acid, indicating high surface coverage with organic material.

As measured by the mercury intrusion porosimetry, for the kaolin samples the amount of the largest pores decreases and the amount of the smallest pores increases with the accumulation of humic acid. For the quartz systems only very high doses of humic acid are reflected in changes of pore size distribution.
Körnung von Saproliten als methodenabhängige Größe
Authors: Häfele Stephan , Wiechmann Horst
Published: February 2007

In Saproliten und daraus entstandenen jüngeren Böden liegt ein stark vorverwittertes, meist kaolinisiertes und mehr oder weniger mürbes Material vor, welches durch Wurzeln, Frost, Bearbeitung usw. aufgearbeitet wird. Die Körnung dieser Böden hängt weitgehend von der Aufteilung der Saprolitfragmente ab. Bei der Korngrößenbestimmung bedingen die mechanische Vorzerkleinerung des Saprolits, die Dispergierung und besonders die Anwendung von Ultraschall unterschiedlicher Intensität Verschiebungen in den Körnungsfraktionen. So konnte in Basaltsaproliten der Tongehalt durch praxisüblichen „harten”︁ Ultraschall um das zwei‐ bis dreifache auf über 60% erhöht werden. Es wird eine Konvention zur mechanischen Vorbehandlung und Körnungsanalyse von Saproliten und saprolitischen Böden vorgeschlagen.
Zur statistischen Abhängigkeit der Adsorption verschiedener Herbizidwirkstoffe vom Anteil der organischen Substanz in Böden
Authors: Meyer‐Windel Sigrid , Ketelsen Hark , Widmoser Peter
Published: February 2007

Die Adsorption der herbiziden Pflanzenschutzmittel (PSM) Atrazin, Terbuthylazin, Chlortoluron und Isoproturon wird an 24, für Schleswig‐Holstein typischen Bodenhorizonten, mit Freundlich‐Adsorptionsisothermen beschrieben. Die Abhängigkeit der Adsorptionskonstanten (KFr) jedes PSM vom Anteil organischen Kohlenstoffs (fOC) der Bodenhorizonte wurde überprüft. Die wirkstoffspezifischen, vom organischen Kohlenstoffanteil unabhängigen Adsorptionskennwerte (K'OC‐Werte), weisen für jedes PSM eine beträchtliche Streuung auf (VK ca. 50%); ihre Verwendung wie auch die eines durch lineare Regression von KFr und fOC ermittelten KOC‐Wertes muß daher im Einzelfall kritisch geprüft werden. Die experimentell abgeleiteten K'OC‐ bzw. KOC‐Werte der PSM nehmen in der Rangfolge Terbuthylazin > Chlortoluron > Atrazin ≅ Isoproturon ab. Die substratunabhängigen Ermittlungen von KOC‐Werten anhand von KOW‐Werten oder Wasserlöslichkeiten der PSM ergaben dagegen deutliche Veränderungen dieser Rangfolge. Insbesondere so hergeleitete KOC‐Werte können daher zu Fehleinschätzungen führen. Der Anstieg der Adsorptionskonstanten KFr mit steigendem fOC für Atrazin, Terbuthylazin and Isoproturon ist überproportional und wird daher besser von einem Polynom 2. Ordnung beschrieben als von einer linearen Beziehung, während er für Chlortoluron über den betrachteten fOC‐Bereich proportional bleibt.
Niederschlags‐Chemismus und atmosphärische Element‐Deposition in einem an der Nordseeküste von Schleswig‐Holstein gelegenen Agrarökosystem
Authors: Mansfeldt Tim , Blume Hans‐Peter
Published: February 2007

Ziel dieser Arbeit war es, den Niederschlags‐Chemismus und die Höhe der atmosphärischen Elementeinträge eines küstennah gelegenen Agrarökosystems in Dithmarschen, Schleswig‐Holstein, zu ermitteln.

Hierzu wurde die atmosphärische Deposition von November 1989 bis Oktober 1991 mittels ständig offenen Sammlern auf Wochenbasis gesammelt. Im Deponat wurden die elektrische Leitfähigkeit, das pH und die Na+‐, K+‐, Mg2+‐, Ca2+‐, NH4+‐, Cl−‐, NO3−‐ und SO42−‐Konzentrationen bestimmt.

Das durchschnittliche volumengewichtete pH lag bei 5,5 und die durchschnittliche elektrische Leitfähigkeit bei 92 μS cm−1. Natrium und Cl− waren mit 64% und 76% (Äquivalentkonzentration) die wichtigsten Ionen im Deponat und spiegeln den starken Einfluß des Meeres wieder. Der Anteil der Meeresalkalinität an Neutralisationsreaktionen in der Deposition ist zu vernachlässigen (1%). Dagegen waren NH3 mit 63% und Carbonate mit 36% an einer Neutralisation beteiligt.

Die Einträge betrugen 1990 und 1991 97,0 und 51,7 kg Na+ ha−1, 6,2 und 4,0 kg K+ ha−1, 15,0 und 8,4 kg Mg2+ ha−1, 13,2 und 10,4 kg Ca2+ ha−1, 12,3 und 9,5 kg NH4+‐N ha−1, 8,0 und 5,9 kg NO3−‐N ha−1, 168 und 83,1 kg Cl− ha−1 sowie 19,1 und 12,7 kg SO42−‐S ha−1. Im Jahr 1990 häufiger auftretende Westwinde in Verbindung mit höheren Windgeschwindigkeiten verursachten höhere Einträge marinen Ursprungs.

Berechnet auf Cl−‐Basis waren im Mittel der Jahre 93% des Na+, 55% des K+ 74% des Mg2+, 24% des Ca2+ und 36% des SO42− mariner Herkunft.

Atmosphärische Einträge marinen Ursprungs deckten die Mg‐Entzüge zu 39–72% und die S‐Entzüge zu 21–37%. Die Nordsee stellt somit für diese Elemente eine wichtige Quelle im Hinblick auf die Versorgung von Pflanzen dar.
Modelling of sorption experiments and seepage data of an Amazonian Ultisol subsoil under cropping fallow
Authors: Ludwig Bernard , Hölscher Dirk , Khanna Partap , Prenzel Jürgen , Fölster Horst
Published: February 2007

The results of physico‐chemical investigations of an Ultisol subsoil under a 2‐year old fallow in eastern Amazonia are presented. Subsoil chemistry was studied using 4 different approaches: i) concentrations of H, Na, K, Ca, Mg, Mn, Al, and Fe in seepage water were measured under field conditions, ii) the equilibrium soil chemistry was studied in sequential batch experiments where the soil was treated with different solutions, iii) results of batch experiments were simulated with a chemical equilibrium model, and iv) the seepage data were calculated using selectivity coefficients obtained by modelling the batch experiments. The model included multiple cation exchange, precipitation/dissolution of Al(OH)3 and inorganic complexation. Cation selectivity coefficients were pKx/Casel: X = Na: 0.3, K: 0.8, Mg: −0.1, and Al: 0.4. The amount of cations sorbed ranged from −0.2 to 2.0 (K), −0.7 to 2.3 (Mg), −1.6 to 1.8 (Ca), −4.8 to 3.6 (Al) and 0.0 to 8.5 (Na) mmolc kg−1. The model predictions were good with values lying within 0.3 pH units (for the pH range 3.7 to 7.2), and 3% of CEC for individual cations. The most important proton buffer reaction seemed to be the dissolution of gibbsite and a large release of Al into the soil solution. When selectivity coefficients obtained by the modelling procedure were used to predict the field data for cation concentrations in the seepage water, they decreased in the following order: Na > K > Ca > Mg > Al. These calculated values were similar to the measured order: Na > Ca > K ≈ Mg > Al.

Thus the options for managing these soils should be carefully chosen to avoid soil acidification which may result from inappropriate use of fertilizer during the cropping period.
Oberflächenstrukturen und Eigenschaften von Permafrostböden im nordsibirischen Lena‐Delta
Authors: Mueller Klaus
Published: February 2007

Die Landoberflächen des Lena‐Delta zeigen durchgehend Polygonstrukturen mit einzelnen Pingos und Dünen. Es treten so bezeichnete verlandete, versumpfte und offene Polygone mit Gelic Gleysols und Gelic Histosols (gelundic phase) auf. Die Böden zeigen nur geringe Kryoturbations‐ und Verwitterungsmerkmale. Sie haben sehr hohe Gehalte an Schluff und kaum zersetzter organischer Substanz bis in Bodentiefen weit unter die sommerliche Grenze des Permafrostes. Durch jährlichen Zuwachs an organischem Material und periodische Überschwemmungen wachsen die Böden auf. Das führt zu einer laufenden Anhebung der Permafrostgrenze und damit verbunden zu einer dauerhaften Festlegung pflanzlichen Materials. Die Böden können somit als wirkungsvolle C‐Senken betrachtet werden. Auf dem Scheitel eines untersuchten Pingo entwickelte sich aufgrund der windexponierten Lage, der guten Entwässerung und der höheren Bodentemperaturen bei tiefer liegender sommerlicher Permafrostgrenze ein Gleyi‐gelic Cambisol. Dieser Boden zeigt keine Kryoturbation und vergleichsweise geringere Gehalte an organischer Substanz. Durch periglaziäre Entmischung und Abwehungen zeigt der obere Bodenbereich hohe Sand‐ und geringe Schluffgehalte.
Zu Eigenschaften, Horizontaufbau und Gliederung der „Haftnässepseudogleye”︁
Authors: Müller Werner
Published: February 2007

Der Begriff „Haftnässe”︁ bezieht sich auf Böden mit Sg‐Horizonten, in denen eine länger anhaltende Vernässung mit Luftmangel auftreten kann, ohne daß freies Wasser vorhanden ist. Die Haftnässe wird durch Wasser verursacht, das in Poren mit einem Äquivalentdurchmesser von 0,2 bis 50 μm in einem Saugspannungsbereich von pF 1,8 bis 4,2 auftritt, wenn der Horizont gleichzeitig nur eine geringe Luftkapazität aufweist. Es wird vornehmlich durch Kapillarkräfte bewegt und ist pflanzenverfügbar (nutzbare Feldkapazität).

Bei einer Reihe von Böden treten unter den Sg‐Horizonten grobporenreiche, durchlüftete Horizonte auf, die die kapillaren Wasserleitbahnen unterbrechen. In ihnen werden reduzierte Eisenverbindungen aus den Sg‐Horizonten oxidiert und als rostfarbene Eisenflecken ausgefällt. Derartige Horizonte sind oft durch hängende Menisken feuchter, als darüber und darunter liegende Horizonte. Für sie wird das Symbol So vorgeschlagen.

Die bei den Haft(nässepseudo)gleyen auftretenden Horizontfolgen führen zu einer unterschiedlichen Kontinuität der vornehmlich kapillaren Wasserleitbahnen. Auf Grund dieser Horizontfolgen wird folgende Differenzierung in Subtypen vorgeschlagen:

„(Norm‐)Haft(nässepseudo)gley (SHn)”︁ mit der Horizontfolge Ah/Sg/(II)So und Übergangssubtypen zur Parabraun‐ oder Fahlerde,

„Mächtiger Haft(nässepseudo)gley (SHm)”︁ mit der Horizontfolge Ah/Sg1/Sg2 und Übergangssubtypen zu Stau(wasserpseudo)gley, Gley, Aue oder Marsch.
Quaternary stratigraphy of the fladen area, central North Sea: A multidisciplinary study
Authors: Sejrup H. P. , Aarseth I. , Ellingsen K. L. , Reither E. , Jansen E. , Løvlie R. , Bent A. , Brigham‐Grette J. , Larsen E. , Stoker M.
Published: February 2007

Based on detailed stratigraphic investigations on a 200.6m long core (BGS borehole No. 81/26) from the Fladen Ground area (British sector), core material from the Sleipner field (Norwegian sector) and shallow seismic profiles between the core‐sites, the following conclusions are drawn: (1) The North Sea was glaciated sometime during th elaterpart of Matuyama reversed period. A complete glacial‐interglacial‐glacial cycle is recorded in these sediments. (2) In a period of marine sedimentation in the Middle Pleistocene, a transgression‐regression cycle under boreal‐arctic regime is recorded. (3) The Fladen area has subsided between 0.9 and 0.6 m/ka through the later parts of the Quaternary (4) A major glacial event dated at between 130 and 200 ka is recorded as a thick till unit in 81/26. This till, which was deposited by ice moving from the southwest (Scotland), probably represents a period when the Scandinavian and British ice sheets coalesced in the North Sea. (5) Based on the seismic data and the stratigraphy of the Sleipner core, an ice‐free, open embayment/dry land is favoured for the central North Sea during the Late Weichselian. (6) From the amino‐acid data, it is shown that there has been an episodic style of sedimentation through the Quaternary. (7) of the investigated sediments (which span the last 1 mill. year) ca 98% have been deposited under arctic to boreal‐arctic conditions.
Late devensian ice sheet in the western Grampians, Scotland
Authors: Thorp Peter W.
Published: February 2007

A radial pattern of ice flow of the last ice sheet in the largest source area of ice (c. 5000 km2) in the British Isles in western Scotland is demonstrated by the dispersal of indicator erratics and by patterns of striae, friction cracks and ice‐moulded landforms. Three major ice domes and the principal ice divide are identified in the western Grampians. The ice domes coincided with the highest mountain blocks while it is inferred that the alignment of many of the pre‐existing valleys controlled much of the outflow of ice, forming ice streams within the ice sheet. The importance of the Rannoch Moor basin as a radial provider of ice to surrounding areas was apparently less significant than has hitherto been considered. Ice flowed into and across the southern part of the basin from the principal ice divide located to the west and south. No evidence has yet been found that would support a model of an eastward‐migrating ice divide either during the build‐up or during the deglaciation of the Late Devensian ice sheet.
Palaeoecological investigations towards the reconstruction of the post‐glacial environment at Lough Doo, County Mayo, Ireland
Authors: O'connell Michael , Mitchell Frazer J. G. , Readman Peter W. , Doherty Terence J. , Murray Declan A.
Published: February 2007

Results of palaeoecological studies involving pollen analytical, chemical and palaeomagnetic investigations on a 3 m core from Lough Doo, NE County Mayo, are presented. The record, which commences shortly after 7000 BP, shows a sharp Alnus expansion coinciding with a decline in Pius at 6400 BP, an elm decline taking place in the context of severe soil erosion and the final decline of Pinus occurring as the chemical record indicates onset of severe reducing conditions in the catchment. Pine becomes extinct at or shortly before 3200 BP in the context of increased farming activity and the expansion of blanket bog in the adjacent upland areas. A later feature (c. 1880 BP) is the expansion of Taxus to 7.1% of total pollen.

On the basis of the palynological evidence, it is concluded that there were no major Neolithic Landnam phases, which contrasts sharply with the evidence for widespread woodland clearance and the laying out of extensive and regular field systems in the northern coastal part of County Mayo. In the upper part of the core a severe inversion of 14C dates is recorded. On the basis of the palaeomagnetic and pollen evidence this began at c. 1500 BP and is considered to have been initiated in the context of woodland clearance and a renewal in farming activity.
Ice‐wedge casts and relict polygonal patterns in Scandinavia
Authors: Svensson Harald
Published: February 2007

Ice‐wedge casts in Scandinavia frequently occur in three regions: (a) southwestern Jutland (outside the limit of the Weichselian glaciation); (b) southwestern Sweden; and (c) northernmost Norway. The latter two areas are both early deglaciated regions. Characteristics of casts in vertical sections are discussed with reference to the host and infilling material. Aerial photographs provide an effective tool for detecting relict ice‐wedge polygons (crop marks, micromorphology). Experience from present‐day permafrost regions with active ice‐wedge formation helps to explain the palaeoclimatic significance of the relict polygons. Attempts to establish the ages of formation are discussed from a methodological point of view.
The significance of cryoturbation phenomena in environmental reconstruction
Authors: Van Vliet‐Lanoë Brigitte
Published: February 2007

Cryoturbation results mainly from differential heave related to (1) drainage and thermal conditions and (2) frost susceptibility. Loadcasting and cryostatic pressures are restricted to wet soils such as pure silt or silty sand. The translocation of fine particles resulting from repeated freezing and thawing can promote frost susceptibility in a previously non‐susceptible material, as well as a loss in stability of the surface horizons (liquefaction). Small and metric scale cryoturbations can be explained by this process. Large scale deformations and injections may be related to abnormal liquefaction not necessarily associated with frost. Regular patterns are associated with fissure nets. Upturned injections in a downslope direction attest to cryoturbation and frost creep. A lowering of the water table promotes the formation of drop‐like cryoturbations, most of which can be related to seasonal frost in imperfectly to poorly drained soils. They are not indicative of permafrost except in well drained situations or in the case of flat bottomed involutions.
An Ipswichian fluvial deposit at Fulbeck, Lincolnshire and the chronology of the Trent terraces
Authors: Brandon Allan , Sumbler Michael G.
Published: February 2007

Mammalian fossils recently discovered near Fulbeck in Lincolnshire, include abundant hippopotamus, suggesting an Ipswichian date for the Fulbeck Sand and Gravel (new name). These deposits mark a former course of the River Witham; clasts indicate derivation from outcrops of Jurassic rocks and chalky till to the south and south‐east. The relationship of the Fulbeck Sand and Gravel to the terrace deposits of the River Trent necessitates a revised chronology. The Balderton Sand and Gravel (new name), laid down by the Trent along its former course to the Lincoln Gap, is shown to be older than the Ipswichian Fulbeck Sand and Gravel, and was probably deposited during the Wolstonian Stage. The Eagle Moor Sand and Gravel (new name), probably glaciofluvial outwash from the chalky tills of the region, is considerably older than the Balderton Sand and Gravel and, together with the tills, is assigned to the early part of the Wolstonian, or the Anglian glacial Stage. It is suggested that the Balderton and Eagle Moor terraces equate with the lower and upper facets of the composite Hilton Terrace of the Middle Trent.
Variations in the pattern and rate of isostatic uplift indicated by a comparison of Holocene sea‐level curves from Scotland
Authors: Haggart B. Andrew
Published: February 2007

Differences in the timing of maxima and minima and shape between sea‐level curves from the western Forth valley, lower Strathearn, inner Moray Firth and eastern Solway Firth areas of Scotland are interpreted as being due to differences in isostatic uplift and different methodologies used to interpret the basic data. Possible changes in the relative rates of uplift between areas suggest that the practice of applying the western Forth ‘model’ of relative sea‐level change to other parts of Scotland must be questioned.
Reconstructing past glacier dynamics and erosion from glacial geomorphic evidence: Snowdon, North Wales
Authors: Sharp Martin , Dowdeswell Julian A. , Gemmell J. Campbell
Published: February 2007

Bedrock surfaces exposed around Llyn Llydaw, North Wales demonstrate contrasting styles of erosion beneath a Late Devensian ice sheet and a Loch Lomond Stadial (LLS) valley glacier. Ice sheet erosion involved lee‐side fracturing, surface fracture wear and abrasive wear, while LLS erosion was primarily by abrasive wear. Preservation of ice sheet erosional features indicates limited rates of erosion during the LLS. Analysis of the geometry and distribution of erosional markings suggests that the low erosional capacity of the LLS glacier was due to a low basal sliding velocity. This prevented the formation of lee‐side cavities, reduced the debris flux over the bed and minimised particle‐bed contact loads. Reconstructions of the mass balance and geometry of the LLS glacier indicate that most of its balance velocity could be achieved by internal deformation alone. A combination of low subglacial water pressures and an unusually rough substrate explain the low sliding velocities. High bed roughness is due to the absence of leeside cavities and a change in flow orientation between ice sheet and LLS times, which meant that the LLS glacier was in contact with roughness elements which were generated in cavities beneath the ice sheet.
Loess—palaeosol sequence in Kashmir: Correlation of mineral magnetic stratigraphy with the marine palaeoclimatic record
Authors: Gupta S. K. , Sharma P. , Juyal N. , Agrawal D. P.
Published: February 2007

In this paper we use the mineral magnetic data (χ and χfd) to stratigraphically correlate different loess‐palaeosol profiles in Kashmir Valley. The two available thermoluminescence (TL) chronologies on the Kashmir loess profiles have been reinterpreted to identify the soil of the Last Interglacial (ca. 125 000 yr BP). We show that the mineral magnetic data correlates well with the global marine δ18O record. This correlation has revealed the well‐known Milankovich periodicities of 40 ka and 20 ka in the loess‐palaeosol record. On the basis of this study, we conclude that loess deposition in the Kashmir Valley started around 200 ka and not 350 ka ago as suggested by earlier workers, and that magnetic susceptibility variations provide a tool to decipher climatic changes from loess‐palaeosol sequences.
Morphology and stratigraphy from several deglaciations in the Transtrand Mountains, western Sweden
Authors: Kleman Johan , BorgströM Ingmar , Robertsson Ann‐Marie , Lilliesköld Marianne
Published: February 2007

The Transtrand Mountains, western Sweden, are characterised by an abundance of glaciofluvial meltwater channels. Crossing lateral channels and channel systems overprinted by fluting occur at several localities. Drainage channel systems from three older deglaciations are interpreted to have been preserved despite overriding by later ice sheets. Deep sections, machine excavated into the summit surface of the Hundfjället Mountain, revealed the presence of two lower diamictons into which two older generations of lateral channels were cut, and subsequently buried by a Late Weichselian basal till. Buried frost‐sorted structures, and frost‐fractured bedrock below the lowermost till, indicate the repeated occurrence of periglacial condil conditions. An organic layer between the two older units yielded an infinite radiocarbon age of > 45000 yr BP. The pollen content of this layer indicates a local mountain heath flora dominated by ericaceous dwarf shrubs and graminids. The climate phase is interstadial or the beginning or end of an interglacial. The different diamictons also display different pollen spectra. During the last deglaciation the ice flow was from the north‐northeast. The second youngest system of drainage channels corresponds to ice flow from approximately west‐northwest. There are still older traces of separate deglaciation events from the east and north. A frozen bed is interpreted to have been the standard basal regime for the last ice sheets to cover the Transtrand Mountains.
Allt Odhar and Dalcharn: Two pre‐Late Devensian/Late Weichselian sites in northern Scotland
Authors: Walker M. J. C. , Merritt J. W. , Auton C. A. , Coope C. R. , Field M. H. , Heijnis H. , Taylor B. J.
Published: February 2007

The lithostratigraphy and biostratigraphy of two sites (Allt Odhar and Dalcharn) in north‐central Scotland are described, where pollen spectra of temperate affinity have been obtained from organic deposits that underlie till. The pollen record from Allt Odhar, in association with evidence from plant macrofossils and Coleoptera, shows the expansion of birch woodland and its eventual replacement by open grassland under a climatic regime slightly cooler than that prevailing in the northern highlands of Scotland at the present day. The organic sediments accumulated during an Early Devensian interstadial episode, which has been dated by the uranium series disequilibrium method to ca. 106 ka BP. Evidence for one and possibly two Devensian glaciations may be preserved at the site. The pollen record from Dalcharn, by contrast, reflects the middle and later stages of an interglacial cycle with the transition from pine forest to grassland. The overlying till sequence contains evidence of at least two separate glacial episodes. The age of the warm stage cannot be established precisely on present evidence, but there are indications that it may predate the last (Ipswichian) interglacial. These are the first sites from the mainland of Scotland to provide evidence of wooded conditions during interstadial and interglacial episodes of the Middle/Late Pleistocene.
Late Devensian and Flandrian palaeoenvironmental changes on the Scottish continental shelf west of the Outer Hebrides
Authors: Peacock J. D. , Austin W. E. N. , Selby I. , Graham D. K. , Harland R. , Wilkinson I. P.
Published: February 2007

Examination of two radiocarbon‐dated vibrocores taken from south of St Kilda at a water depth of about 155 m, a short distance within the maximum position of the Late Devensian (Dimlington Stadial) ice sheet, suggests that the St Kilda Basin became free of glacier ice after 15250 yr BP. Sedimentation in a shallow, low energy, high arctic, muddy environment continued until after 13500 yr BP. There followed a higher energy temperate episode during which water depths were roughly about 40 m: this is correlated with the latter part of the Windermere Interstadial and with the warmer interval known in shallow Scottish seas about or a little before 11 000 yr BP. The Loch Lomond (Younger Dryas) Stadial is marked in the vibrocores by the return of muddy sediments and a cold‐water fauna. Relatively shallow water conditions seem to have persisted into the earliest Flandrian, when the water depth was still roughly 60 m, corresponding to a sea‐level in the area 90–100 m below present. It is suggested that pack ice was widespread in the northeast Atlantic before the Windermere Interstadial and also during the Loch Lomond Stadial, when it transported shards of Icelandic volcanic ash into the St Kilda basin. Estimates of sea‐surface temperature for the last part of the Windermere Interstadial are close to those derived from the deep‐sea record for the same period.
Late‐glacial climatic oscillations as recorded in Swiss lake sediments
Authors: Eawag A. F. Lotter , Eicher U. , Siegenthaler U. , Birks H. J. B.
Published: February 2007

Regional pollen assemblage zones for the late‐glacial period of the Swiss Plateau are introduced and defined. They include four major zones (Artemisia, Juniperus—Hippophaë, Betula, Pinus PAZ) with several subzones. Pollen and oxygen‐isotope analyses on lacustrine sediments from several lakes in the area reveal four distinct phases of climatic oscillation in the time period of 13 000‐9500 yr BP.

The first oscillation, termed the Aegelsee fluctuation, occurs shortly before 12 000 yr BP and varve counts suggest its duration was ca. 100 yr. It is characterised by a short decrease in the oxygen isotopes as well as a short increase in NAP associated with a depression in birch pollen values. The second oscillation, which occurs in the δ18O record shortly before the deposition of the Laacher See Tephra (ca. 11 000 yr BP), is termed the Gerzensee fluctuation. It occurs during a pine‐dominated phase and its vegetational effects cannot be determined palynologically. The most prominent regressive phase is the Younger Dryas biozone (ca. 10 700‐10 000 yr BP) characterised by an increase in heliophilous NAP and low δ18O values. The Younger Dryas biozone can often be subdivided palynologically into two parts: a first part rich in grasses and juniper and a second part with higher Filipendula and birch values. During the Preboreal biozone another distinct oscillation is evidenced only in the oxygen isotope ratios.

Comparison of the Swiss oxygen isotope profiles with the Greenland Dye 3 record suggests that not only the three major shifts in the δ18O curves but also the minor ones are closely comparable, suggesting some common climatic control.
Pleistocene stratigraphy in the Devils Hole Area, Central North Sea: Foraminiferal and amino‐acid evidence
Authors: Knudsen Karen Luise , Sejrup Hans Petter
Published: February 2007

A detailed study of the foraminiferal assemblages from the 229.1‐m‐deep core 81/34 in the central North Sea has been combined with a series of measurements of the isoleucine epimerisation of foraminiferal tests. A total of 17 foraminiferal zones have been established and both the faunal compositions and the amino‐acid values suggest that a major part of the sequence represents deposits of early and middle Pleistocene age. Only the uppermost zone is referred to the late Pleistocene.

The sequence mainly comprises a series of marine zones from cold periods, but with some barren, possibly non‐marine intervals in between. Only two of the foraminiferal zones can be referred to interglacial periods. The oldest one of these, defined here as the Devils Hole Interglacial, may belong to the latter part of the Cromerian Complex, while the upper warm interval is correlated with the Holsteinian of northwest Europe on the basis of its amino‐acid values.

A detailed stratigraphical correlation between core 81/34 and the neighbouring core 81/29 is suggested on the basis of their foraminiferal content, palaeomagnetic evidence and amino‐acid measurements from both cores. A characteristic feature of both sequences is that most of the Quaternary record is missing. Similar episodic patterns of deposition and erosion have been reported previously from the North Sea area.
Palaeoecology of a late Allerød peat bed at Godøy, western Norway
Authors: Birks Hilary H. , Lemdahl Geoffrey , Svendsen John Inge , Landvik Jon Y.
Published: February 2007

A peat bed found under solifluction deposits on Godøya island, western Norway, accumulated during a few decades around 11 000 yr BP, at the end of the Allerød period of the Late Weichselian. Palaeoecological investigations showed a local vegetation succession on wet sand culminating in a mire community dominated byCarex nigra. Periodic flooding brought in sand and silt, which decreased as drainage was impeded sufficiently for standing water to develop. The surrounding terrestrial vegetation was dominated bySalixscrub, with some open heath and alpine habitats nearby. Apart from two aquatic species, the 29 insect taxa recorded are characteristic of alpine heaths, plant litter (underSalixscrub) and stream‐sides. Their remains, together with the terrestrial plant macrofossils, were washed into the mire from nearby.

Because the fossils are locally derived, the environmental reconstructions are of the actual conditions at Godøy at ca. 11 000 yr BP. Palaeotemperature estimates from beetles and plants are in agreement. The coleopteran estimates (Mutual Climatic Range Method) suggest mean July temperatures of 10–13°C, slightly cooler than today (13.5°), and January temperatures between +1 and −10°C, similar to or much colder than today. Summer temperature estimates from individual plant taxa indicate that temperatures during the Allerød period were similar to today's, but estimates from the reconstructed vegetation and timber‐line positions give estimates up to 3.5° cooler. Temperatures fell 2.5–7.5°C at the Younger Dryas. This abrupt and severe cooling initiated the solifluction processes on Godøya that buried the peat.

The Godøy peat bed and its contained fossils provide a rare glimpse of Allerød biota and environments at the local (site) scale.
Stratigraphy and palaeoecology of a possible interglacial site, northernmost Ellesmere Island, Canada
Authors: Evans D. J. A. , Mott R. J.
Published: February 2007

An extensive stratigraphic section at Cape Alfred Ernest on the Wootton Peninsula, northwest Ellesmere Island contains six lithofacies which appear to record two glacial phases separated by an organic layer. (1) A lower massive gravel records a pre‐ice advance outwash phase; (2) massive fine‐grained sediments record a period of non‐glacial marine deposition when sea‐level was higher than present; (3) a massive diamicton records the advance of ice across the site; (4) intermediate stratified beds record supraglacial and proglacial outwash, and include an organic layer; (5) massive diamicton grading down‐valley to stratified diamicton and then massive, sheared diamicton, overlain by laminated fine‐grained sediments with dropstones, recording the last (late Wisconsinan) glaciation; (6) upward‐coarsening sands and gravels record proglacial outwash and grade to raised marine deltas.

Radiocarbon dates of 39270 ± 640 and > 51000 yr BP were obtained on samples from the organic layer by accelerator mass spectrometry and conventional radiocarbon dating, respectively. Palaeoecological data suggest that the organics accumulated in a wet sedge meadow environment when the climate was warmer than present. Stratigraphic considerations suggest that the organic layer represents an interglacial interval which, if valid, indicates that the site constitutes the northernmost interglacial stratigraphy in the Canadian Arctic. Alternatively, the organic layer may date to Plio‐Pleistocene times.
The middle pleistocene deposits of Waverley Wood Pit, Warwickshire, England
Authors: Shotton F. W. , Keen D. H. , Coope G. R. , Currant A. P. , Gibbard P. L. , Aalto M. , Peglar S. M. , Robinson J. E.
Published: February 2007

A complex of channels underlying the Baginton‐Lillington Gravel (Baginton Formation) at Waverley Wood Quarry, Warwickshire is described. Fossil pollen and plant macrofossils, Coleoptera, Ostracoda, Mollusca and Mammalia are described from the channel‐fill deposits. Consideration of all the evidence allows the identification of four separate stages of channel fill which largely occurred under a cool temperate climate. At the top of Channel 2 evidence for a cold, continental climatic episode can be recognised, suggesting that the whole complex was deposited under a fluctuating climate at the end of a temperate stage. At two levels in the channels human artefacts were recovered confirming the presence of Palaeolithic people in Warwickshire during the deposition of the sediments. Amino‐acid geochronology suggests an age within the ‘Cromerian Complex’ Stage for the channels. The small vertebrate and molluscan faunas indicate that the deposits are no older than the latter part of the ‘Cromerian Complex’ Stage of East Anglia. The regional stratigraphic significance of the Waverley Wood succession is outlined.
Fissure‐fill and tunnel‐fill sediments: expressions of permafrost and increased hydrostatic pressure
Authors: Kumpulainen Risto A.
Published: February 2007

A spectacular network of fissure fillings and pipes (tunnels) cuts Quaternary gravelly delta deposits northeast of Myvatn, precisely on the spreading axis of the North Icelandic rift zone. The delta was formed in an ice‐contact lake during deglaciation towards the end of the last glaciation. Subsequently the lake was drained and permafrost conditions developed in these poorly sorted gravel deposits. Hydrostatic pressure was transmitted from the adjacent glacier to the non‐frozen core of the delta beneath the discontinuous permafrost crust and the seasonally frozen active layer. Owing to increased hydrostatic pressure, a network of subhorizontal to vertical fissures was opened along the taliks. In these fissures free ground‐water flow and sediment transport were established. Tunnel erosion and probably also seepage erosion were associated with these fissures. Subsequently, the fissures and tunnels were filled by laminated fine sediments interbedded with poorly sorted material resulting in the formation of fissure‐fill sediments and tunnel‐fill sediments.
The Weichselian Late‐glacial in southwestern Europe (Iberian Peninsula, Pyrenees, Massif Central, northern Apennines)
Authors: de Beaulieu J. ‐L. , Andrieu V. , Ponel P. , Reille M. , Lowe J. J.
Published: February 2007

This paper presents a summary of Late‐glacial environmental changes in southwestern Europe (lberian Peninsula, Pyrenees, Massif Central and the northern Apennines). The emphasis is on palaeoclimatic interpretations inferred from key sites in the region from which the most detailed records are available and which have been radiocarbon dated. The earliest evidence for climatic improvement following the end of the last glacial stage is dated to ca. 15 ka BP and is found at a few sites only. By 13 ka BP, a more widespread and marked climatic improvement is evident, although it is difficult to be precise in the timing and magnitude of the event. There are significant variations in detail between the Late‐glacial records, but evidence for a significant cooling correlated with the Younger Dryas event is widespread throughout the region. Just two sites in the region provide evidence for an earlier, less emphatic phase of climatic cooling, which is tentatively equated with the ‘Older Dryas’ of continental northern Europe. Dry conditions appear to have predominated throughout the region in the later part of the Younger Dryas and the early Holocene.
Glaciotectonics of the ltterbeck ‐ Uelsen push moraines, Germany
Authors: Kluiving Sjoerd J.
Published: February 2007

The two Saalian push moraines of ltterbeck ‐ Uelsen, formed during the Older Saalian glaciation, consist of Tertiary and Quaternary deposits. Locally, glaciofluvial deposits are prominent as a result of reworking of older deposits by meltwater. The push moraines are built up from a number of imbricated and folded structural units, which have moved laterally and, in part, frontally from two glacial basins. Dominant structures are large, shallow and flat‐lying glaciotectonic nappes that have been displaced over distances of at lest 1 km in the direction of tectonic transport. Overprinting relations of two deformation phases give a relative age difference between the two push morianes.