Utwory czwartorzędowe Pogórza Rożnowskiego w Karpatach Zachodnich

Witold Zuchiewicz

Abstrakt


QUATERNARY DEPOSITS OF THE ROŻNÓW FOOTHILLS, POLISH WEST CARPATHIANS

Summary
Quaternary deposits of the Rożnów Foothills include regoliths, landslide colluvia, solifluction-deluvial covers, loess-like deposits, organogenic muds and calcareous tufas, as well as fluvial deposits of different age and glacifluvial pebbles and sands. The oldest Quaternary witnessed two episodes of increased fluvial activity during which gravel series of erosion-accumulational terraces, 85-110 m and 65-80 m high, were deposited at the time of the Otwock and Narewian coolings. Two lower situated terrace steps (35 - 60 m) ware formed during the South-Polish (Nidanian and Sanian) glacial stages. Fluvial deposits of the lower (Sanian) step include erratic boulders and glacifluvial sands and pebbles, deposited during a recession phase of the ice lobe which, at its maximum extent, protrused far into the Dunajec valley, up to the Czchów and Piaski Druikow region. After the following erosional phase, associated with the Masovian (Great) interglacial stage, another episode of fluvial activity took place, leading to the shaping of two erosion-accumulational terraces (15 - 30 m), in the Middle Polish glacial stages. At that time, deluvial deposits were accumulated an older terrace steps. At that time, deluvial deposits were accumulated an older terrace steps. In the last glacial stage (Vistulian), pebbles, sands and alluvial loams, building 6 - 13 m high terraces, were deposited. Talus feet were, in turn, being covered with solifluction-deluvial and loess-like deposits. Silt-sandy deluvia and loesses encroached upon fluvial deposits of the penultimate and ultimate glacial stages. During the middle and late Pleistocene, under periglacial climatic conditions, intensive physical weathering led to the formation of rock fields and 0.5-2 m thick regolith covers. The lower parts of slopes were then subject to solifluction processes and, during anaglacial and kataglacial phases, also to sheet-washing. In Holocene times, several phases of increased humidity and, hence, increased flood frequency, have appeared. The valley bottoms have been infilled with fluvial deposits composing 2-4 terrace steps. The slopes have been modeled by landslides and landslips, whilst within small valleys and the foot of landslide tongues, calcareous tufas and organogenic deposits have accumulated.

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