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Dumpstones as records of overturning ice rafts in a Weichselian proglacial lake (Rügen Island, NE Germany)

Pisarska-Jamroży M., Van-Loon A. J. T., Bronikowska M.

Geological Quarterly

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2018

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Vol. 62, No. 4

917-924

EN

Dumpstones and dropstones up to 0.8 m in size occur in a silty/sandy Weichselian glaciolacustrine succession near Dwasieden on Rügen Island in the SW Baltic Sea (NE Germany). The deposits are exceptional because two levels of dumpstones and dropstones are present, suggesting two dumping phases interrupting characteristic fine-grained glaciolacustrine sedimentation. Plastic downwarping of sediments below the dumpstones and dropstones result in soft-sediment deformation structures. The distribution and orientation of the long axes of the clasts are useful tools for the reconstruction of the state of the lake bottom, as well as for the water depth. The horizontal position of the gravels and boulders (parallel to the bedding) suggests deposition in relatively shallow-water. The dumping events are linked to iceberg rafting in a glacial lake during the Weichselian Glaciation (MIS 2).

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Kame or moraine? A sedimentological study of a glaciomarginal landform at Niedźwiedziny (Great Polish Lowland)

Ewert-Krzemieniewska A.

Geologos

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2014

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Vol. 20, No. 3

167--181

EN

A sedimentary succession in a gravel pit at Niedźwiedziny was investigated in order to determine its origin: kame or moraine. The gravel pit is located in an isolated hill of approx. 600 m long and 250–400 m wide. The succession is built of glaciofluvial deposits: a sandy/gravelly unit in the lower and middle parts, overlain by diamicton. Five lithofacies have been distinguished, which represent two facies associations: (1) a fluvial association evolving from a high-energy to a transitional to a shallow braided river on an alluvial fan, and (2) an association of cohesive deposits representing a glacigenic mass flow. The interpretation is based mainly on palaeocurrent data and differs from conclusions by earlier investigators. The ice-marginal zone is characterised by a large variety of glaciomarginal forms. Their sedimentology, morphology and palaeogeography are determined by successive phases of deglaciation. The results of the present study show that the character of the deglaciation in the study area changed with time from frontal to areal deglaciation.

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Heavy minerals as a tool to reconstruct river activity during the Weichselian glaciation (Toruń Basin, Poland)

Weckwerth Piotr, Chabowski Marek

Geologos

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2013

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Vol. 19, No. 1-2

25--46

EN

The heavy-mineral composition of the Weichselian fluvial successions deposited by an ephemeral meandering river and by a sand-bed braided river in the Toruń Basin (central Poland) was analysed. On the basis of a lithofacies analysis, in combination with the composition of the heavy-mineral assemblages, the fluvial processes and river-channel morphology were reconstructed. This allows determining the provenance of the fluvial deposits and the rivers’ discharge regimes. A model is proposed which can explain the changes in the amount of individual minerals in the fluvial sediments of different ages under the conditions of the oscillating Scandinavian ice sheet. The model assumes that, during the ice-sheet advances, the proglacial streams supplied large amounts of heavy minerals that were less resistant to mechanical abrasion. During the main phase of the ice-sheet retreat, the distance between the ice sheet and the Toruń Basin increased, and the amount of non-resistant minerals diminished as a result of sediment reworking in proglacial rivers. Due to the unique location of the Toruń Basin at the front of the Scandinavian ice sheet during the Weichselian glaciation, the heavy-mineral assemblages in the fluvial deposits form a valuable tool for the recognition of the ice-sheet extent.

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Diamicton in Besiekierz (Central Poland) : how to avoid misinterpretation of superposition in Quaternary geology

Czubla P., Forysiak J., Twardy J.

Geological Quarterly

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2013

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Vol. 57, No. 4

629–-636

EN

Diamicton in Biesiekierz (central Poland), whose age and origin has long provoked debate, is located above unquestionable Eemian biogenic deposits documented by palynological and Cladocera analyses. Petrographically, this diamicton shows some similarities to Warthanian till. Lithologically, it shows considerable weathering of the deposit, a possible selection of the component minerals and addition of dispersed biogenic matter. The results obtained so far as well as the palaeomorphological situation indicate that the diamicton is reworked till material, as are sand intercalations within it. Given the organic content of this diamicton, we infer that a long-term agricultural exploitation of its immediate surroundings was the main factor behind colluvial reworking and displacement occurring above the Eemian biogenic deposits in the fossil depression.

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Sedimentary record of a Pleistocene ice-sheet interlobate zone (NE Poland)

Gruszka Beata, Morawski Wojciech, Zieliński Tomasz

Geologos

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2012

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Vol. 18, No. 2

65--81

EN

Well developed NE-SW trending corridors of outwash in NE Poland are associated with a series of lakes with a similar direction of elongation. The glaciofluvial corridor under study consists of parallel ridges with associated channels and kames. The deposits are flanked by till and hummocky terrain. The gravel ridges are composed of sand and gravel deposits that are cross-stratified, massive or graded, and that contain cut-and-fill structures and large intra-clasts of sand and gravel. Locally the deposits show normal faults. The succession of one of the ridges is interpreted to reflect the infilling of a braided channel in a crevasse. Sedimentation took place in some phases when the ice-sheet regime changed from active to stagnant. Sandy-gravel ridges occur within this complex perpendicular to the Weichselian icesheet margin. The corridor is interpreted as an interlobate area in the zone between the Warmia and Mazury ice lobes. The braided-channel deposits are not comparable to typical Polish sandurs. The lithofacies characteristics show higher energy conditions, and the channels are deeper than those typical of Pleistocene lowland sandurs. The sand and gravel ridges are interpreted as interlobate eskers.

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Palynology of Late Pleistocene varved clays from ice-dammed lakes at Lębork and Złocieniec (north-western Poland) - preliminary results

Gedl Przemysław

Geologos

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2011

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Vol. 17, No. 1

49--59

EN

Samples collected from Late Pleistocene varved clays of the Vistulian (Weichselian) glaciation exposed at Lębork and Złocieniec (Gardno and Pomeranian phases, respectively) yielded palynological contents that are related to the different lithologies composing the varves. The dark-coloured clay units contain very small amounts of palynological material. The lighter-coloured, much thicker coarser units yielded large amounts of organic particles consisting of predominantly palynodebris of terrestrial plants, sporomorphs and aquatic palynomorphs. The latter include fresh-water and marine phytoplankton. All particles were presumably washed out from the pre-Quaternary basement or from erratic material. This is indicated by the dinoflagellate-cyst assemblages, which represent Cretaceous and Palaeogene taxa. The large amounts of organic particles in the light-coloured layers indicate high-energy meltwaters streams, which washed them out, transported them and deposited them in ice-dammed lakes. The barren layers and those with lower amounts of organic particles were deposited during calm, presumably winter, periods, when the energy of the meltwater streams was much lower.

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New approach to garnet redistribution during aeolian transport

Lisá L., Buriánek D., Uher P.

Geological Quarterly

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2009

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Vol. 53, No 3

333-340

EN

Garnet composition within Late Pleistocene (Weichselian) loess and loess-like deposits was studied in 13 samples of sediment heavy mineral fractions from Moravia and Silesia (Czech Republic). Four areas differing in garnet chemistry were identified, and some regional trends in garnet composition changes were documented. The data obtained support the generally accepted conclu ion of prevailing westerly winds during Weichselian loess deposition. Metamorphic rocks of the Bohemian Massif together with contributions fromig neous (mainly granitic) and sedimentary rocks were indicated as a source for the Weichselian loess and loess-like deposits studied. Local differences in garnet composition depend on the basement source rocks, on prevailing wind direction, on regional geomorphology and on transport distance.

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O możliwościach rekonstrukcji paleotemperatur vistulianu na podstawie kopalnych zespołów ptaków

Lorenc Michał

Geologos

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2008

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Vol. 14, No. 1

91--106

PL

Pochodzące z vistulianu szczątki ptaków znane są w Polsce niemal wyłącznie z osadów jaskiń i schronisk skalnych, w sumie z 18 stanowisk. Relatywnie liczne są wyłącznie szczątki pochodzące ze środkowego i późnego vistulianu. W artykule podsumowano zamieszczone w literaturze dane dotyczące występowania i zróżnicowania gatunkowego kości ptaków w vistuliańskich osadach powyższych 18 stanowisk. Zespoły ptaków z vistuliańskich osadów poszczególnych jaskiń i schronisk skalnych stanowiły często podstawę rekonstrukcji paleośrodowiska, rzadziej paleoklimatu. W artykule podsumowano średnie temperatury lipca, które na podstawie tych zespołów oszacowano do tej pory dla niektórych faz klimatycznych vistulianu. Większość temperatur określono używając metody obliczania wskaźników termicznych, według Demarcq & Mourer-Chauvire (1976) i przeliczania wartości tych wskaźników na °C, według Lorenca (2007). Metody te zostały ogólnie scharakteryzowane. Prezentowane temperatury odnoszą się do następujących faz klimatycznych vistulianu: późny vistulian (bölling, starszy dryas, alleröd, młodszy dryas), późny plenivistulian, środkowy plenivistulian (denekamp, hengelo), wczesny plenivistulian (schalkholz) i wczesny vistulian (odderade). Wskazano mocne i słabe strony rekonstrukcji paleotemperatur na podstawie powyższych zespołów ptaków.

EN

Vistulian bird-bone remains are known in Poland almost exclusively from sediments of 18 caves and rockshelters in the Kraków-Częstochowa Upland, the Podhale Depression and the Holy Cross Mountains. Only remains from the Middle and Late Vistulian are relatively abundant. The present contribution summarizes literature data on the occurrence and species diversity of bird-bone remains from the 18 sites mentioned above. The bird-bone assemblages from the caves and rock-shelters were often used to reconstruct the then palaeoenvironment, more rarely the palaeoclimate. Analysis of the bird-bone assemblages indicates average July temperatures for some Vistulian intervals, viz. the Late Vistulian (Bölling, Older Dryas, Alleröd, Younger Dryas), Late Plenivistulian, Middle Plenivistulian (Denekamp, Hengelo), Early Plenivistulian (Schalkholz) and Early Vistulian (Odderade). Most of the temperatures were assessed through thermal indices (Demarcq & Mourer-Chauvire 1976), but they were estimated by Lorenc’s (2007) method as well. Both methods are explained in the present contribution. In addition, the advantages and disadvantages of palaeotemperature reconstruction on the basis of bird-bone assemblages are specified.

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Optical dating of a late quaternary sediment sequence from Sokli, Northern Finland

Alexanderson H., Eskola K. O., Helmens K. F.

Geochronometria

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2008

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Vol. 32

51-59

EN

Interstadial and non-glacial stadial sediments collected in boreholes from Sokli in northeastern Finland have been dated by optically stimulated luminescence on quartz and feldspar grains. The quartz OSL ages follow stratigraphic order, with one exception, and support the litho- and biostratigraphical correlation with the NW European mainland climate-stratigraphy and the marine oxygen-isotope stages. Feldspar IRSL dates generally overestimate the age, probably due to incomplete bleaching. The data show that during the last glacial cycle north-eastern Finland was not glaciated until MIS 5b, around 90 ka. Interstadial conditions occurred around ∼94 ka (MIS 5c), ∼74-80 ka (MIS 5a) and 42-54 ka (MIS 3). The OSL ages have large standard errors mainly due to small sample sizes, relatively poor luminescence characteristics and uncertainties in dose-rate determinations.

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Middle and Upper Weichselian Pleniglacial fluvial erosion and sedimenta- tion phases in Southwestern Poland, and their relationship to Scandinavian ice sheet build-up and retreat

Krzyszkowski D., Kuszell T.

Annales Societatis Geologorum Poloniae

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2007

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Vol. 77, No 1

17-38

EN

The sequence of Weichselian sediments and processes in SW Poland is almost identical to that of central Poland. Generally, three fluvial units occur, comprising silts and sands coarsening upwards to silts, sands and gravels, with aeolian deposits on top. This suggests very uniform processes throughout the palaeogeographic zone. To the south of this zone, there was extensive loess deposition and glacial deposition to the north. Climatic conditions during the Middle and Upper Weichselian Pleniglacial in SW Poland were similar to those in central Poland and northwestern Europe, though the period of 47-43 kyrs BP was slightly milder in SW Poland (shrub tundra, forest-tundra). Climatic conditions during the periods 38-27 kyrs BP and 23-18 kyrs BP were very uniform throughout central Europe, including SW Poland, though there may have been a strong north-south climatic gradient during the former period, as data from the loessic zone indicate at least patches of boreal forest or forest-tundra conditions in SW Poland at that time. It is also possible that there was a Middle Weichselian Pleniglacial interstadial with a lower age boundary at 25,900 ą 700 years BP, characterised by Pinus-Picea forest with no heliophytes. This interstadial represents the last mild period before the advance of the late Weichselian ice sheet into SW Poland. The Weichselian fluvial deposition of SW and central Poland may have been punctuated by at least three major erosional phases, characterised by similar incision depths during the cold stages. Erosion took place, with certainty, at around 75-60 kyrs BP (Lower Pleniglacial) and 27 kyrs BP, very probably at around 23/22 kyrs and possibly at around 40 kyrs BP, and valley aggradation occurred during the milder stages. The Upper Pleniglacial was characterised by valley aggradation, associated with southward ice sheet advance and restricted fluvial outflow. However, the frequent Middle Pleniglacial Weichselian climatic oscillations did not initiate sedimentation and erosion, they controlled only river discharge and type of fluvial sedimentation and aeolian activity. The occurrence of the erosional and aggradational phases were controlled by the changes in ice volume in Scandinavia, ice sheet build-up and retreat, respectively.

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The Young Baltic advance in the western Baltic depression

Stephan H. J.

Geological Quarterly

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2001

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Vol. 45, No 4

359-364

EN

The last Weichselian glacial advance into the western Baltic depression, the so-called "Young Baltic" glacier advance is described. In the southern Baltic depression, ice masses flowed westwards and fanned out in the western Baltic region where they terminated along the end moraines of the East Jutland advance (Denmark), Sehberg advance (Schleswig-Holstein) and Mecklenburg advance (Mecklenburg-Vorpommern). The westward ice advance is likely due to the rapid melting of Norwegian and Swedish ice masses which had previously blocked the more easterly ice masses from draining to the west and north-west. The deposition of a purely eastern-sourced debris facies by a Baltic ice stream in the far west might be the result of ice/bed separation during flow.