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This paper presents evidence for a limnological response to the Laacher See eruption (LSE) as detected in lake sediments from Nahe, northern Germany. The sediment section of the Allerød period dating to between 13 422 and 12 708 cal. a BP is preserved in annual laminations. Within this section, the LSE was identified as a cryptotephra layer (12 944±44 cal. a BP). Microfacies analysis, continuous high‐resolution geochemical measurements and pollen analyses enabled a high‐resolution reconstruction of environmental change. The older part of the Allerød (c. 13 422 to 12 943 cal. a BP) was characterized by relatively stable sedimentation conditions. Evidence for windier conditions dating to c. 13 160 to 13 080 cal. a BP probably reflects the Gerzensee oscillation. Pronounced changes of the lake sedimentation followed the LSE. Four unusually thick varves with increased amounts of allochthonous material indicate serious disturbance of the local environment immediately after the LSE, related to increased storminess and/or the occurrence of high intensity rainfall events. A pronounced reduction of biogenic silica accumulation for c. 60 years after the LSE could reflect a period of acidification. Indications of a simultaneous lake level increase until c. 60 years after the LSE are in line with the supposed reduced evapotranspiration associated with cooler conditions. About 120 years after the LSE, increased oxygen access at the lake bottom, allochthonous input and Cl fluxes point to an onset of increasingly stronger westerly winds, probably as a long‐term response to the LSE. This supports the idea of a southward shift of the mid‐latitude westerlies wind system within the interval between the LSE and the beginning of the Younger Dryas. The pace of the southwards shift of this wind system decreased from 10 km a−1 in the initial phase (40–120 years after LSE) to 6 km a−1 in the later phase (120–200 years after LSE). [ABSTRACT FROM AUTHOR]

To spatially characterize the palaeolakeshore environment at the archaeological kill site Schöningen 13 II‐4 of the Middle Pleistocene Reinsdorf sequence, in‐depth palynological, geochemical, aquatic microfossil and archaeological analyses were undertaken on sediment sections with an average thickness of about 15 cm, concordantly overlain by faunal remains, dominated by horse, from the unique 'Spear Horizon' layers of the 1995 excavation campaign. The data reveal a distinctive lake level drop, documented by the change from a carbonate‐rich lake marl to a carbonate‐free organic mud with increased carbon content and decreasing C/N, Si/Al, Si/K and Fe/Al ratios, indicating a higher pedogenic supply of organic matter and drier conditions at the site. Compared with older, similar transitional phases of lake level changes occurring within the Reinsdorf sequence, it is important that these youngest sediments are undisturbed, indicating continuous development. Ostracod and diatom analyses indicate a lowering water level with higher salinities and rich aquatic vegetation. Mesorheophilic ostracod species along with tychoplanktic diatom taxa point to flowing waters and turbulence at the lakeshore, presumably related to spring‐fed streams originating from nearby highlands. Palynological results reveal a very diverse zonal vegetation pattern around the palaeolakeshore considering an area of investigation of approximately 50 × 75 m and a tessellated type of regional vegetation during the formation of the archaeological horizons. On topographically lower elevated areas, birch groves and taxa favouring wet, marshy conditions such as Cyperaceae, indicative of terrestrialization, were predominating, while other stands of this transitional phase reveal a very dry, grass‐dominated steppe woodland favouring a rich wildlife with a striking number of megaherbivores. Our results suggest that the lithological differences of the 'Spear Horizon' layers containing the archaeological finds were due to their respective topographical situation and that the layers were deposited almost simultaneously during the beginning of the lake level drop. Human activities seem to have concentrated in sparsely vegetated areas along the palaeolakeshore, rather than in areas of adjacent denser birch swamp forest stands. [ABSTRACT FROM AUTHOR]

This paper focuses upon the youngest terraces of the Moselle and its tributary the Meurthe ( NE France and SW Germany). It includes research on several sections, in particular the key sections of Golbey- Pré Droué and Thörnich- Hochrech (located in the vicinity of the Vosges Massif and in the Rhenish Massif, respectively), and the use of the Optically Stimulated Luminescence ( OSL) dating method. Our investigations made it possible to obtain a more robust chronostratigraphical framework and to update the previous model of fluvial response to climate change. The results demonstrate that the Moselle terrace M3 (first terrace formed after the capture of the Upper Moselle by the Palaeo- Meurthe) has the same age from the Vosges to the Rhenish Massif. The formation of this terrace included two main periods of sedimentation attributed to the Late Saalian ( MIS 6) and the Early Weichselian ( MIS 5), respectively. They were separated by a major episode of fluvial erosion that may be allocated to the MIS 6-5 transition on the basis of chronological and sedimentological evidence. This erosion led to the removal of most of the MIS 6 deposits, whereas the MIS 5 deposits have been widely preserved following the subsequent ( MIS 5-4) terrace incision. This evolution somewhat contrasts with that observed in the Sarre valley, the main tributary of the Moselle, and with many fluvial systems in western Europe, which show better preservation of deposits from cold periods. This atypical behaviour is explained by the relationship between the fluvial evolution and the glaciers covering the upper Moselle catchment ( Vosges Massif) during the Pleistocene cold periods. [ABSTRACT FROM AUTHOR]

In this paper we briefly compare previously published data on four lateglacial sediment profiles from lakes Holzmaar and Meerfelder Maar in the Eifel region. Two of these profiles (one from each lake) are varvedated, whereas the other two pollen profiles are on depth scales. In general, the palynological signal in all profiles compares well, proving the regional validity of the individual data sets. There are some discrepancies between Holzmaar and Meerfelder Maar, however, mainly concerning varve dating of major lateglacial features, and these are explained after detailed correlation using a combination of varve dating and palynological signals. The result is a consistent varve-dated biostratigraphy for the Lateglacial in the Eifel region. Moreover, it is demonstrated that a combination of varve chronology and high resolution palynostratigraphy in several lake profiles enables even gaps of a few decades up to a few centuries to be detected, thus providing a valuable tool for precise regional palaeoenvironmental study. This multi-core study on two lakes from the same region demonstrates the likelihood of undetected errors in single-core studies on non-varved sediments. [ABSTRACT FROM AUTHOR]

The laminated sediment of Lake Holzmaar (Germany) has provided a continuous varve chronology for the last 3500 varve years (vy) and beyond that a floating varve chronology back to more than 22 500 vy BP. This chronology in calendar years, in combination with palynology, enables us to determine the timing and the magnitude of Lateglacial and Early Holocene environmental changes on land (from 13 838 to 10 930 vy BP). The palynological diagram has a mean time resolution of 27 vy between samples. This paper establishes for the first time the biozonation for Lake Holzmaar below the Laacher See Tephra. Fifteen pollen subzones grouped in four biozones are defined by cluster analysis. After a period disturbed by microturbidites, only a part of the Bølling is present. Three cold periods have been evidenced by pollen analyses: the Older Dryas (96-vy-long), the Younger Dryas (654-vy-long) and the Rammelbeek phase (237-vy-long). The Allerød (883-vy-long) is bipartite with a first Betula-dominated period followed by a Pinus-dominated one. The Younger Dryas is also bipartite, with first a decrease of winter temperatures along with a change to a more continental climate. It is followed by a drier phase with a second decrease in temperatures, probably this time also affecting summer temperatures. The Preboreal is 702-yr-long. The duration of most phases corresponds to published records, except for that of the Younger Dryas. Cluster and rate-of-change analyses indicate a sharp change in the terrestrial vegetation assemblages that may be caused by a sedimentary hiatus of erosive origin during this cold and dry period. As a result, the chronology of Holzmaar has to be revised most likely below the middle of the Younger Dryas. Comparison with the varve record of Meerfelder Maar, a neighbour maar lake, suggests adding 320 vy below 12 025 vy. [ABSTRACT FROM AUTHOR]

Lake‐level reconstructions are a key tool in hydro‐climate reconstructions, based on the assumption that lake‐level changes primarily reflect climatic changes. Although it is known that land cover changes can affect evapotranspiration and groundwater formation, this factor commonly receives little attention in the interpretation of past lake‐level changes. To address this issue in more detail, we explore the effects of land cover change on Holocene lake‐level fluctuations in Lake Tiefer See in the lowlands of northeastern Germany. We reconstruct lake‐level changes based on the analysis of 28 sediment records from different water depths and from the shore. We compare the results with land cover changes inferred from pollen data. We also apply hydrological modelling to quantify effects of land cover change on evapotranspiration and the lake level. Our reconstruction shows an overall lake‐level amplitude of about 10 m during the Holocene, with the highest fluctuations during the Early and Late Holocene. Only smaller fluctuations during the Middle Holocene can unambiguously be attributed to climatic fluctuations because the land cover was stable during that period. Fluctuations during the Early and Late Holocene are at least partly related to changes in natural and anthropogenic land cover. For several intervals the reconstructed lake‐level changes agree well with variations in modelled groundwater recharge inferred from land cover changes. In general, the observed amplitudes of lake‐level fluctuations are larger than expected from climatic changes alone and thus underline that land cover changes in lake catchments must be considered in climatic interpretations of past lake‐level fluctuations. [ABSTRACT FROM AUTHOR]

The archaeological sites in the open‐cast mine of Schöningen, Germany, represent outstanding archives for understanding Middle Pleistocene interglacial–glacial transitions and human adaption. Aquatic microfossil and pollen assemblages from the 'Reinsdorf sequence', likely correlated to Marine Isotope Stage 9, document environmental changes from a thermal maximum to succeeding glacial conditions recorded in two sequences of excavation sites 12 II and 13 II. Multi‐proxy analyses enable detailed reconstruction of lake‐shore and landscape developments despite variable microfossil preservation in changing carbonate‐ and organic‐rich deposits. Rich aquatic vegetation with abundant charophytes suggests repeated phases with water depths of 0.5–2 m at site 13 II, while even greater temporary depths are deduced for 12 II DB. Mesorheophilic and mesotitanophilic ostracod species indicate stream inflows with medium–low calcium contents of >18 mg Ca L–1 originating from nearby springs. Diatoms point to meso‐eutrophic conditions and an alkaline pH of the lake water. Interglacial conditions with thermophile forests but no aquatic microfossils preserved, suggesting a dry or only temporarily flooded site, mark the beginning of the sequence. Continuous presence of aquatic organisms and overall dominance of small tychoplanktonic diatoms during a subsequent cool steppe phase provide evidence for increased water depths and unstable habitats characterized by erosion and probably prolonged periods of lake ice cover. During the succeeding boreal forest‐steppe phase, surface runoff into the productive, shallow lake decreased due to a more extensive vegetation cover. Concurrently, intensified groundwater input in contact with the nearby salt wall caused elevated salinities. Following a lake level drop, stream inflows and lake levels increased again towards the end of the Reinsdorf sequence and promoted development of a diverse fauna and flora at the lake shore; thereby maintaining an attractive living and hunting environment for early humans during a phase of generally cooler temperatures and landscape instability at the transition into a glacial period. [ABSTRACT FROM AUTHOR]

The continuing development of analytical methods for investigating sedimentary records calls for iterative re‐examination of existing data sets obtained on loess‐palaeosol sequences (LPS) as archives of palaeoenvironmental change. Here, we re‐investigate two LPS (Hecklingen, Zilly) in the northern Harz foreland, Germany, being of interest due to their proximity to the Scandinavian Ice Sheet (SIS) and the position between oceanic climatic influence further west and continental influence towards the east. First, we established new quartz OSL and polymineral IRSL chronologies. Both methods show concordant ages in the upper part of the Hecklingen profile (~20–40 ka), but in the lower part IRSL underestimates OSL ages by up to ~15 ka for the period 40–60 ka. Interpretations hence refer to the OSL data set. Second, we applied Bayesian age‐depth modelling to data sets from Hecklingen to resolve inversions in the original ages, also reducing averaged 1σ uncertainty by ~19% (OSL) and ~12% (IRSL). Modelled chronologies point out phases of increased (MIS 2, early MIS 3) and reduced (middle and late MIS 3) sedimentation, but interpretation of numerical rates is problematic because of intense erosion and slope wash particularly during MIS 3. Finally, previously obtained grain‐size data were re‐investigated by end member modelling analyses. Three fundamental grain‐size distributions (loadings) explain the measured data sets and offer information on intensity and – combined with modelled OSL ages – timing of geomorphic processes. We interpret the loadings to represent (i) primary loess accumulation, (ii) postdepositional pedogenesis and/or input of aeolian fine fractions, and (iii) input of coarse aeolian material and/or slope wash. The applied modelling tools facilitate detailed understanding of site‐formation through time, allowing us to correlate a strong peak in mean grain size at ~26–24 ka to the maximum extent of the SIS and increased influence of easterly winds. [ABSTRACT FROM AUTHOR]

We revise the conceptual model of calcite varves and present, for the first time, a dual lake monitoring study in two alkaline lakes providing new insights into the seasonal sedimentation processes forming these varves. The study lakes, Tiefer See in NE Germany and Czechowskie in N Poland, have distinct morphology and bathymetry, and therefore, they are ideal to decipher local effects on seasonal deposition. The monitoring setup in both lakes is largely identical and includes instrumental observation of (i) meteorological parameters, (ii) chemical profiling of the lake water column including water sampling, and (iii) sediment trapping at both bi‐weekly and monthly intervals. We then compare our monitoring data with varve micro‐facies in the sediment record. One main finding is that calcite varves form complex laminae triplets rather than simple couplets as commonly thought. Sedimentation of varve sub‐layers in both lakes is largely dependent on the lake mixing dynamics and results from the same seasonality, commencing with diatom blooms in spring turning into a pulse of calcite precipitation in summer and terminating with a re‐suspension layer in autumn and winter, composed of calcite patches, plant fragments and benthic diatoms. Despite the common seasonal cycle, the share of each of these depositional phases in the total annual sediment yield is different between the lakes. In Lake Tiefer See calcite sedimentation has the highest yields, whereas in Lake Czechowskie, the so far underestimated re‐suspension sub‐layer dominates the sediment accumulation. Even in undisturbed varved sediments, re‐suspended material becomes integrated in the sediment fabric and makes up an important share of calcite varves. Thus, while the biogeochemical lake cycle defines the varves' autochthonous components and micro‐facies, the physical setting plays an important role in determining the varve sub‐layers' proportion. [ABSTRACT FROM AUTHOR]

Glacially dislocated fossiliferous clay – hitherto called Cyprina clay– and associated Pleistocene sediments are exposed at the northeastern German coast. They were uplifted as glacial rafts from a position of about 30 m below the sea level and incorporated into glaciotectonic complexes of Dornbusch (Hiddensee), Arkona (Rügen) and Greifswalder Oie during the ice advances of the Last Glacial Maximum (LGM). Optically stimulated luminescence (OSL) ages of the fossil‐bearing clay and the overlying glacifluvial/lacustrine successions give insights into Late Saalian, Eemian and Early to Middle Weichselian development of the southern Baltic Sea area. The age data especially support the observation of changing environmental conditions prior to the Eemian warm period as suggested by the fossil record. A high‐arctic brackish fauna documented in a lower reddish‐grey clay is followed by a more boreal brackish‐marine to marine fauna in the overlying olive and/or greenish‐grey clay. This implies conditions of glacial meltwater running to the northwest during the deglaciation phase of the last Saalian Warthe ice advance and inflow of cold marine water from the North Atlantic area along the margin of the Scandinavian Ice Sheet into the Skagerrak and the Kattegat. Subsequently, water with higher salinity entered the mouths and channels of large rivers crossing the southern Baltic Sea area from SE to NW comparable with those of the Oder and Vistula rivers. Eemian Cyprina clay deposits with lusitanian faunal elements are not exposed in the study area but occur in Denmark and northwestern Germany. To distinguish the different facies types and age of the clay, we introduce the stratigraphical term Vitt Formation for the Late Saalian Cyprina clay in NE Germany, comprising Roundstonia, Portlandia and Arctica members – each with characteristic microfossil species. [ABSTRACT FROM AUTHOR]

Here we present the results of a detailed cryptotephra investigation through the Lateglacial to early Holocene transition, from a new sediment core record obtained from Lake Hämelsee, Germany. Two tephra horizons, the Laacher See Tephra (Eifel Volcanic Field) and the Saksunarvatn Ash (Iceland), have been previously described in this partially varved sediment record, indicating the potential of the location as an important Lateglacial tephrochronological site in northwest Europe. We have identified three further tephra horizons, which we correlate to: the c. 12.1 ka BP Vedde Ash (Iceland), the c. 11 ka BP Ulmener Maar tephra (Eifel Volcanic Field) and the c. 10.8 ka BP Askja-S tephra (Iceland). Three additional cryptotephra deposits have been found (locally named HÄM_T1616, HÄM_T1470 and HÄM_T1456-1455), which cannot be correlated to any known eruption at present. Geochemical analysis of the deposits suggests that these cryptotephras most likely have an Icelandic origin. Our discoveries provide age constraints for the new sediment records from Lake Hämelsee and enable direct stratigraphical correlations to be made with other tephra-bearing sites across Europe. The new tephrostratigraphical record, within a partially varved Lateglacial sediment record, highlights the importance of Lake Hämelsee as a key site within the European tephra lattice. [ABSTRACT FROM AUTHOR]

Here we present a multi-proxy investigation of the Klein Klütz Höved ( KKH) coastal cliff section in northeastern Germany, involving lithofacies analysis, micromorphology, micropalaeontology, palynology and luminescence dating of quartz and feldspar. We subdivide the local stratigraphy into three depositional phases. (i) Following a Saalian advance ( MIS 6) of the Scandinavian Ice Sheet, the penultimate deglaciation (Termination II) at the site occurred between c. 139 and 134 ka, leading to the establishment of a braided river system and lacustrine basins under arctic-subarctic climate conditions. (ii) In the initial phase of the Eemian interglacial lacustrine deposits were formed, containing warm-water ostracods and a pollen spectrum indicating gradual expansion of woodlands eventually containing thermophile deciduous forest elements. A correlation of the local pollen assemblages with Eemian reference records from central Europe suggests that fewer than 750 years of the last interglacial period are preserved at KKH. The occurrence of brackish ostracods dates the onset of the Eemian marine transgression at the section at c. 300-750 years after the beginning of the last interglacial period. (iii) Directly above the Eemian record a ~10-m-thick sedimentary succession of MIS 2 age was deposited, implying a significant hiatus of c. 90 ka encompassing the time from middle and upper MIS 5e to late MIS 3. During the Late Weichselian, KKH featured a depositional shift from (glacio-)lacustrine to subglacial to recessional terminoglacial facies, with the first documented Weichselian ice advance post-dating 20±2 ka. Overall, the KKH section represents an exceptional sedimentary archive for palaeoenvironmental reconstructions, covering the period from the Saalian glaciation and subsequent Termination II to the early Eemian and Late Weichselian. The results refine the existing palaeogeographical and geochronological models of the late Quaternary history in the southwestern Baltic Sea area and allow correlations with other reference records in a wider area. [ABSTRACT FROM AUTHOR]

Loess-paleosol sequences are important terrestrial archives of palaeoenvironmental change. Such sequences are rich in pedogenic carbonate, the oxygen and carbon isotopic values of which can provide important palaeoenvironmental information. Although some studies have pioneered the use of O and C isotopes in loess-paleosol sequences, they are not routinely used as palaeoclimate proxies. In this study we analysed the sedimentology, micromorphology, geochronology and isotopic geochemistry of a Middle Pleistocene loess-paleosol section, located at Kärlich, Germany. The section studied correlates with the Elsterian glacial ( MIS 12) and Holsteinian interglacial ( MIS 11). Embedded tephra layers yielded 40 Ar/39 Ar ages of 466±3 ka, 447±1 ka and 361±3 ka. The sedimentology and micromorphology of the sequence record a shift from accretionary loess accumulation ( MIS 12) to prolonged pedogenesis at a stable land surface ( MIS 11). Soil carbonate δ18 O values record an enrichment of ∼3‰ during the accumulation of the loess, reaching peak values comparable with those found in the MIS 11 soil. The δ18 O signal is interpreted as reflecting temperature, highlighting the potential of δ18 O analysis of European loess soil carbonates as a means of reconstructing palaeotemperature history. [ABSTRACT FROM AUTHOR]

The Late Pleistocene was characterized by rapid climate oscillations with alternation of warm and cold periods that lasted up to several thousand years. Although much work has been carried out on the palaeoclimate reconstruction, a direct correlation of ice-core, marine and terrestrial records is still difficult. Here we present new data from late Middle Pleniglacial to Lateglacial alluvial-fan and aeolian sand-sheet deposits in northwestern Germany. Records of Late Pleniglacial alluvial fans in central Europe are very rare, and OSL dating is used to determine the timing of fan aggradation. In contrast to fluvial systems that commonly show a delay between climate change and incision/aggradation, the small alluvial-fan systems of the Senne area responded rapidly to climatic changes and therefore act as important terrestrial climate archives for this time span. The onset of alluvial-fan deposition correlates with the climate change from warm to cold at the end of MIS 3 (29.3±3.2 ka). Strong fan progradation started at 24.4±2.8 ka and may be related to a period of higher humidity. The vertical stacking pattern of sedimentary facies and channel styles indicate a subsequrent overall decrease in water and sediment supply, with less sustained discharges and more sporadic runoffs from the catchment area, corresponding to an increasing aridity in central Europe during the Late Pleniglacial. Major phases of channel incision and fan aggradation may have been controlled by millennial-scale Dansgaard- Oeschger cycles. The incision of channel systems is attributed to unstable climate phases at cold-warm (dry-wet) or warm-cold (wet-dry) transitions. The alluvial-fan deposits are bounded by an erosion surface and are overlain by aeolian sand-sheets that were periodically affected by flash-floods. This unconformity might be correlated with the Beuningen Gravel Bed, which is an important marker horizon in deposits of the Late Pleniglacial resulting from deflation under polar desert conditions. The deposition of aeolian sand-sheet systems (19.6±2.1 to 13.1±1.5 ka) indicates a rapid increase in aridity at the end of the Late Pleniglacial. Intercalated flash-floods deposits and palaeosols ( Finow type) point to temporarily wet conditions during the Lateglacial. The formation of an ephemeral channel network probably marks the warm-cold transition from the Allerød to the Younger Dryas. [ABSTRACT FROM AUTHOR]

Menzies, J. & Ellwanger, D. 2010: Insights into subglacial processes inferred from the micromorphological analyses of complex diamicton stratigraphy near Illmensee-Lichtenegg, Höchsten, Germany. Boreas, 10.1111/j.1502-3885.2010.00194.x. ISSN 0300-9483. Investigations of a 30-m-high section of Pleistocene sediments at Illmensee-Lichtenegg, Höchsten in Baden-Württemberg provide detailed information on subglacial conditions beneath the Rhine Glacier outlet of the Alpine ice sheet in southern Germany. The sediment exposure extends from an upper cemented sand and gravel (Deckenschotter) into diamictic units that extend down to weathered Molasse bedrock. The exposure reveals sediments symptomatic of active syndepositional stress/strain processes ongoing beneath the ice sheet. Macrosedimentology reveals diamicton subfacies units and a strong uni-direction of ice motion based on clast fabric analyses. At the microscale level, thin-section analyses provide a substantially clearer picture of the dynamics of subglacial sediment deformation and till emplacement. Evidence based on detailed micromorphological analyses reveals microstructural strain and depositional markers that indicate a subglacial environment of ongoing soft bed deformation in which the diamictons can be readily identified as subglacial tills. Within this subglacial environment, distinct changes in pore-water pressure and sediment rheology can be detected. These changes reveal fluctuating conditions of progressive, non-pervasive deformation associated with rapid changes in effective stress and shear strain leading to till emplacement. This site, through the application of micromorphology, increases our understanding of localized subglacial conditions and till formation. [ABSTRACT FROM AUTHOR]

A new sea-level curve (MHW, mean high water level) for the southern North Sea is presented, spanning the last 10 000 years and based on new data recently obtained along the German coast. The 118 dates were selected from basal as well as intercalated peats of the Holocene sequence and archaeological dates from the last 3000 years. Because of different MHW levels along the German North Sea coast, all data were corrected to the standard tide gauge at Wilhelmshaven to make them comparable. Special advantages of this area for sea-level reconstructions are negligible tectonic and isostatic subsidence and the absence of coastal barrier systems that might have mitigated or masked sea-level changes. Changes of water level had therefore immediate consequences for the facies and could be dated exactly. The chronostratigraphic Calais–Dunkirk system has been improved and adapted to the new data. Altogether seven regressions (R 1–R 7) have been identified, each of them characterized by a distinct decline in sea level. These fluctuations are in accord with the evidence from other parts of the North Sea region. A draft of former North Sea shorelines is presented on the basis of this sea-level curve. [ABSTRACT FROM AUTHOR]

The study area near Chelm in Western Pomerania, NW Poland, is located between the end moraine and outwash plain of the glaciomarginal zone of the Pomeranian Phase (Weichselian glaciation). Four assemblages of deposits are exposed in the Chem pits: gravelly diamictons derived from debrisflows, sandy diamictons derived from hyperconcentrated flows, alternating sand and gravel deposited by sheetflows and sandy deposits filling shallow, braided-stream channels. The first facies association predominates in the proximal part of the transition zone and the last one in the distal part. This spectrum of facies associations, some resembling those of the end moraines and others those of the adjacent outwash plain, is considered to be unique, and is attributed to the formation of an array of coalescent ice-contact fans (‘transition’ fans). Architectural element analysis highlights the southwards change from debrisflow processes accompanied by sheetflows to hyperconcentrated flows and further to channelized streamflow. This transition zone in the present case is c . 1-km wide. It is suggested that analogous transitional zones, with similar or different widths, may have been developed in other glaciomarginal belts and remain to be recognized. [ABSTRACT FROM AUTHOR]

Plant macrofossil remains have been analysed from two raised peat bogs in northern Germany and Denmark. The quantified vegetation reconstructions of each profile were subjected to multivariate analyses to extract records of changing bog surface wetness (BSW), which are interpreted in these rain-fed bogs as being proxy climate signals. Age/depth models were constructed using radiocarbon dates and a number of drier and wetter phases were defined. The records both register cooler/wetter conditions around 2700, 1800 and 1400 cal. yr BP, and at the beginning of the Little Ice Age around AD 1250-1350. These rising bog water tables must have been reflected in poorer conditions for agriculture, and in particular near Dosenmoor where the profile records a catastrophic change to such conditions culminating at 2750-2600 cal. yr BP. [ABSTRACT FROM AUTHOR]

The Coppenbrügge subaqueous ice-contact fan complex of early Saalian age is about 10 km long and up to 10 km wide and is composed of offset-stacked fan clinothems that are transgressive-regressive sequences formed during an overall lake level rise. The individual fan bodies consist of coarse gravel in the ice-proximal part, passing distally into sandy facies and showing large-scale foreset bedding. The iceberg scour recognized in an open-pit outcrop is up to 1.5 m deep, up to 2 m wide and cut in undisturbed mid-fan deposits. The scour-fill can be traced laterally for about 15 m and consists of sheared sand and, in the frontal zone, of downbent overlying strata surrounded by a zone of deformed sediments. The deformed sediment produced by the iceberg keel's shearing of the trough walls is a sand mass containing angular soft-sediment clasts that show internal folds and fractures. The basal surface of the deformed sediment is a nearly horizontal shear plane, steepening up laterally as a discrete thrust and showing a flat-ramp-flat geometry. The scour was formed by the iceberg keel's ploughing the substrate and pushing the sediment sideways and frontally, forming a ridge of deformed sediments at the trough end. This ridge was concurrently eroded by an accompanying meltwater underflow which apparently developed a horseshoe system of scouring vortices around the grounded iceberg. The current's scour was filled with massive, nonstratified sand deposited rapidly from turbulent suspension. The iceberg eventually broke up and its keel part was buried. As these ice fragments gradually melted, the space was closed by normal faulting and downbending of overlying strata. The collapsing scour-fill became partly liquified, and the resulting water-escape structures cut the normal faults and the overlying deposits. Though produced chiefly by tangential shear strain, iceberg-ploughing features are readily distinguishable from other glaciotectonic deformations. They can serve... [ABSTRACT FROM AUTHOR]

An excellent section in the Welzow-Süd open-cast lignite mine in Lower Lusatia, eastern Germany, provided a rare opportunity to study a small (5 m deep), buried subglacial meltwater channel of Saalian age. The channel is steep-sided and distinctly U-shaped. It is separated from undeformed outwash deposits in which it is incised by a sharp erosional contact and it is filled with meltwater sand and till. The till was possibly squeezed into the channel from the adjacent ice/bed interface. Directly beneath the channel, there is a partly truncated diapir of clayey silt, evidencing sediment intrusion into the channel from below. During channel formation, the pressure gradient was oriented from the surrounding sediments into the channel, so that the channel served as a drainage conduit for groundwater from the adjacent subglacial aquifer. The substratum consists largely of sandy aquifers with a total thickness of about 100 m, separated by two aquitards. Channel formation was initiated when hydraulic transmissivity of the bed did not suffice to evacuate all the subglacial meltwater as groundwater flow. As the Welzow-Süd channel belongs to a dense network of subglacial channels in eastern Germany, temporary ice-sheet instability in this region prior to channel formation seems possible. [ABSTRACT FROM AUTHOR]