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Age and sedimentological features of fluvial series in the Toruń Basin and the Drwęca Valley (Poland)

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Weckwerth P. , Przegiętka K. , Chruścińska A. , Woronko B. , Oczkowski H. L.

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tom Vol. 38, no. 4

397-412

EN

The deposits of the Toruń Basin are dominated by a few-metre thick sand series which fill up buried valley-like depressions. In many cases they underlie the Weichselian till which builds up the ice marginal streamway (pradolina) terraces or they are exposed at the basin slopes. As the results of the geological and sedimentological studies, as well as of the dating of the deposits at the sites in the Toruń Basin indicate, the deposits include two fluvial series accumulated before the advancement of the Leszno Phase ice sheet, i.e. in Middle Weichselian and at the beginning of Late Weichselian. The oldest fluvial series connected with the Saalian Glaciation was found at the mouth section of the Drwęca Valley. The fluvial system of the Toruń Basin during Middle Weichselian and at the begin-ning of Late Weichselian developed in two phases of the sand-bed braided river. During the first one the river channel were dominated by large mid-riverbed sandbars, while during the second phase the water flow was smaller and, as a result, low transverse sandbars and two-dimensional dunes devel-oped. Other active river channel also showed low-energy flows, more intensive meandering than in the case of the braided rivers, as well as sandy side-bars. Analysis of the rounding and frosting of the quartz grains indicate that the studied series of the Weichselian sandy deposits represent alluvia of a river which were fed from two diverse sources. The first one might have represented the alluvia of a warm river which transformed its load, while the other one might have mainly carried the underlying Quaternary deposits.

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

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Weckwerth P. , Chabowski M.

Geologos

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2013

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tom 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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Późnoglacjalna i holoceńska ewolucja torfowiska w Dzikowie (Kotlina Toruńska) w świetle badań paleogeograficznych

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Krześlak I. , Andrzejewski L. , Gamrat W. , Kupniewska A.

Landform Analysis

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2013

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tom Vol. 25

95--103

PL

Przedmiotem badań są osady wypełniające zagłębienie wytopiskowe w Dzikowie, we wschodniej części Kotliny Toruńskiej, około 20 km na południowy wschód od Torunia. Analizowane wytopisko oraz sąsiadujące z nim Jezioro Dzikowskie usytuowane są na terasie Wisły. W celu odtworzenia ewolucji środowiska przyrodniczego tego obszaru przeprowadzono badania multidyscyplinarne. Badania geologiczne pozwoliły na określenie maksymalnej miąższości osadów biogenicznych w obrębie analizowanego wytopiska na około 10 m. Szczegółowe analizy paleoekologiczne (geochemiczne, palinologiczne i makroszczątków roślinnych) dostarczyły informacji o zmianach środowiska przyrodniczego w późnym glacjale i holocenie oraz umożliwiły wyodrębnienie kolejnych etapów rozwoju paleojeziora.

EN

The object of current research is core of the bottom sediments of a kettle-hole at the Dzikowo site. Study area is located in the eastern part of the Torun Basin, in the area of the Vistula terrace, approximately 20 km southeast of Toruń. In order to reconstruct the environmental history of this region, multidisciplinary research was carried out. Geological research allowed to determine the maximum thickness of biogenic sediments to approximately 10 m. Detailed paleoecological analyses (palynological, plant macroremains, geochemical) provided information about environmental changes in the Late Glacial and the Holocene and helped to identify stages in the evolution of the paleolake basin.

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Particle-size distribution of channel bars of the lower Vistula between Bobrowniki and Bydgoszcz-Fordon

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Hojan M. , Rurek M.

Geography and Tourism

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2017

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tom Vol. 5, No. 2

97--104

EN

This study presents the diversity of sediments forming sand bars located in the Vistula channel between 695 km and 775 km of its course. The analysed section of the Vistula channel is located in the Toruń Basin. During the fieldwork carried out on 20-21 September 2011, 45 channel bars were identified and sampled. The collected samples were analysed in a laboratory. The obtained results were presented in the form of figures and graphics. The research related to the Vistula bed load performed to date was based on various research methods. The authors applied the sampling method used by Z. Babiński (1992). It was employed also by other authors (Habel, 2013). The obtained results were referred to other studies and the findings clearly indicate that such detailed research must be conducted along the whole middle section of the Lower Vistula valley.