Wyniki wyszukiwania - Biblioteka Nauki

1

Późnovistuliański rozwój sieci rzecznej w rejonie Kotliny Toruńskiej na tle struktur starszego podłoża

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Weckwerth P.

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2007

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nr 04

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Transformacja form korytowych na przykładzie aluwiów piaskodennych rzek roztokowych środkowego vistulianu w Kotlinie Toruńskiej

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Weckwerth P.

Landform Analysis

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2013

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tom Vol. 25

169--177

PL

Wyniki badań sedymentologicznych prowadzonych w północnej części Kotliny Toruńskiej pozwoliły na rozpoznanie zmian architektury środowiska sedymentacji korytowej piaskodennych rzek roztokowych. Rzeki te funkcjonowały w czasie środkowego vistulianu, a ich osady należą do górnego ogniwa formacji z Zielonczyna. Ewolucja sedymentacji fluwialnej następowała w dwóch fazach, którym odpowiadają odmienne formy korytowe. W pierwszej fazie dno koryta roztokowego zdominowane było przez pojedyncze odsypy poprzeczne, zaś w drugiej doszło do rozwoju złożonych odsypów śródkorytowych w wyniku łączenia się odsypów pojedynczych. Główną przyczyną transformacji morfologii koryta rzeki była zmiana reżimu rzek z niwalnego na proglacjalny w czasie awansu czoła lądolodu w stadiale głównym zlodowacenia wisły oraz rozwój systemu pradolinnego. Transformacja morfologii koryt skutkowała także wzrostem tempa agradacji ich osadów.

EN

The results of sedimentological research documented changes of architectural elements of fluvial sedimentary environment of sand-bed braided rivers in the Toruń Basin. These rivers existed at the middle Weichselian and their deposits belong to the upper member of Zielonczyn Formation. The evolution of fluvial sedimentation took place in the two phases, which correspond to different channel macroforms. The braided river bed was dominated by a unit bars during the first phase, while in the second phase were evolved compound mid-channel bars as a result of the amalgamation of unit bars. The main causes of the transformation of river channel morphology in the area of the Toruń Basin during the Weichselian glaciation included changes in river regime from nival to proglacial and development of ice-marginal valley. Transformation of channel morphology resulted in an increase in the aggradation rate.

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Evolution of the Toruń Basin in the Late Weichselian

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Weckwerth P.

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2010

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tom Vol. 14

57-84

EN

The Toruń Basin is the eastern fragment of the Noteć-Warta ice-marginal streamway. Genesis of the Toruń Basin firstly demonstrates processes of erosion and accumulation of meltwaters and the Vistula waters which occur on the background of changes in the height of erosion base and tectonic movements. In the formation of the Toruń Basin one cannot exclude its older, glacial and interglacial assumptions either, as through its location the form is related to the course of the fossil valleys. The article presents functional stages and reorganizational mechanisms of water discharge directions in the Toruń Basin, stimulated by the tectonic activity of the older bed. In the Toruń Basin the following terrace sets can be distinguished: a) the outwash levels formed not so far away from the ice-sheet front, i.e. during the Wąbrzeźno Subphase, b) the distal sections of the outwash (XI, X), c) the Vistula ice-marginal streamway terraces (the transitional terrace and IX), d) the Vistula ice-marginal streamway terraces (VIII-VI) from the period of this river bifurcation at Fordon, and e) lower terraces of the Vistula valley. In the upper part of the Late Weichselian waters formed a system of sandbed braided rivers with changeable flow regime, which initially had higher energy, then reduced energy and high again. This resulted from the ice-sheet front retreat, intensity of its ablation and the inflow of the Vistula waters from the south.

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The deformational structures of the deposits on the Höfdabrekkujökull forefield, Mýrdalsjökull, Iceland

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Olszewski A. , Weckwerth P.

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1999

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tom Vol. 2

63--80

EN

The deformational structures of the developing subglacial (a) substratum deposits and the near Höfdabrekkujökull forefield (b) are the characteristic dynamic parts of the glacio-sedimentological system. These occur in different geomorphological situations: a) under sandur deposits, on the periphery of the fossil embankment of the frontal moraine, on both its distal and proximal slopes, and in the backside depression of this form and b) within the dead ice kettle which was formed in the surface part of the fluvioglacial deposits of the VI sandur level. The older, sub-sandur glaciotectonic discordances, which occur below sandur deposits, represent dynamic structures of two separate glacial advances. Independently of these, deformations of gravitational type also occur. In contrast, the deformations of melt-denudational deposits of the dead ice kettle, surrounded by fluvioglacial deposits, belong to younger (at least several tens years) distortions of gravitational type.

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Morphostructural zones of the Myrdalsjokull ice cap and its main outlet glacier the Hofdabrekkujokull, Iceland

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Olszewski A. , Weckwerth P.

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1999

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tom Vol. 2

51--62

EN

The problem of the morphostructures of glaciers is directly associated, certainly as far as its condition and origin is concerned, with topographical, geomorphological and geological rock foundations, surrounding those at the bedrock of glaciers and also, in case of valley and outflow glaciers, with those of the valley slopes. differentiation of the bedrock of the Myrdalsjokull ice cap leads to a classification of its three morphostructural zones: the glaciomorphological centre (A) which has only slightly varied relief (a,- a4), a northern homogeneous macro-cone of radial flow (B), and a bipartite, supramarginal surrounding slope (C), which has a significant development of outflow glaciers. This differentiation of the subglacial relief and the rocky surrounding of the Hofdabrekkujokull, are manifested in the distribution of various types of foliation and fissuring on its subaerial surface. These, together with its hypsometric formation, were the basis for distinguishing four morphostructural zones of this glacier (Ht - H4). The distinctive morphostructural features of the sector of the bottom zone (H4) of the glacier determine the areas of its particular activity; this reflects the lithogenetic and morphogenetic nature of the subglacial bedrock. The deformed deposits of the bedrock and the nearest forefield represent an important dynamic effect of the glacial system.

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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.