Liczba i wiek zlodowaceń tatrzańskich w świetle datowań termoluminescencyjnych osadów wodnolodowcowych w dorzeczu Białego Dunajca

Leszek Lindner, Jerzy Nitychoruk, Jerzy Butrym

Abstrakt


PROBLEM OF NUMBER AND AGE OF GLACIATIONS IN THE TATRA MTS AGAINST THERMOLUMINESCENCE DATING OF GLACIOFLUVIAL SEDIMENTS IN THE BIAŁY DUNAJEC DRAINAGE BASIN

Summary
The paper presents results of thermoluminescence (TL) datings of sediments that form four, after B. Halicki (8), Pleistocene glaciofluvial levels (I, Il, Ila and III) in the Biały Dunajec drainage basin, northern foreland of the Polish Tatra Mts (Fig. 1, Table) Geologic-geomorphological location of these levels is presented (Figs 2 - 5). The attempt to define strictly chronostratigraphic positions of the levels, as well as succesion, number and age of the Tatra glaciations and their correlation with alpine and Scandinavian ones (Figs 6 - 9) was undertaken. TL datings were done by Dr. J. Butrym from the Thermoluminescence Laboratory, Institute of the Earth Sciences (M. Curie-Skłodowska University in Lublin), in agreement with the published methodological demands (6). The oldest and therefore the highest glaciofluvial sediments of the level I in the Biały Dunajec drainage basin, considered for the relict of the Tatra glaciations during the Mindel (Sanian 2) Glaciation, were TL dated at 443 - 328 ka. These sediments are underlain by clays of the Günz - Mindel Interglacial and cap a glaciofluvial series of the Günz Glaciation (4). Younger glaciofluvial sediments of the level Il, connected with the Riss I (Odranian) Glaciation, were TL dated at 298 - 242 ka what enables their correlation to the TL dated (at 280- 230 ka) sediments of the Mindel Glaciation in the northern foreland of the Alps (Fig. 9). Still younger glaciofluvial sediments of the level Ila, ascribed to the Riss Il (Wartanian) Glaciation, were TL dated at 185 -143 ka in the Biały Dunajec drainage basin. In the northern foreland of the Alps, sediments of this age (180-130 ka) were deposited during the Riss Glaciation (Fig. 9). The youngest and therefore the lowermost glaciofluvial sediments of the level III in the Biały Dunajec drainage basin are connected with the Würm (Vistulian) Glaciation. TL dating of these sediments at 89 - 25 ka enables their univocal correlation to the sediments of the Würm Glaciation (110?-20 ka) in the northern foreland of the Alps (Fig. 9). These data and TL age of glacial sediments of the last glaciation in the Polish Tatra Mts (18) enabled to distinguish three glacial stadials, separated with two interstadial meltings of glaciers (Fig. 8). During the oldest stade (A) that lasted presumably since about 110 ka unilt about 80 ka, the Tatra glaciers occupied a smaller area than during the later two stades (Fig. 6). During the younger i.e. Bystra Stade (B), that lasted from about 70 ka until about 50 ka (Fig. 8), the glaciers were probably most widespread. During the youngest i.e. Białka Stade (C), that lasted from about 30 ka to about 10 ka, the Tatra glaciers had locally smaller extents than during the preceding stade (18). Meltwaters released during retreat of these glaciers favored considerable destruction and dissection of the glaciofluvial level III. They formed the youngest glaciofluvial fan near Nowy Targ (Fig. 1). The glaciers have completely disappeared at the beginning of the Holocene, probably during the first part of the Atlantic Period.