Problem wieku i zasięgu lodowców ostatniego zlodowacenia (Vistulian) w Tatrach Polskich

Abstract

Na podstawie badan geomorfologicznych i geologicznych rzeźby i osadów lodowcowych Tatr Polskich oraz wyników datowań tych osadów metodą termoluminescencji przedstawiono zasięgi i wiek lodowców ostatniego zlodowacenia w Tatrach Polskich. Starsze z tych lodowców, o lokalnie największym zasięgu, rozwijały się około 60-40 tys. lat temu w stadiale Bystrej = stadiałowi Świecia na Niżu Polskim. Młodsze lodowce rozwijały się około 32-10 tys. lat temu w stadiale Białki = stadiałowi głównemu na Niżu Polskim, osiągając najdalszy zasięg w fazie Hurkotnego i kolejno mniejsze zasięgi w fazie Łysej Polany fazie Leszna i Poznania, fazie Włosienicy = fazie pomorskiej i w fazie Doliny Pięciu Stawów Polskich = fazie Gardna. Wymienione stadiały i fazy oddzielone są ociepleniami interstadialnymi i interfazowymi, umożliwiającymi narastanie w tutejszych jaskiniach nacieków węglanowych datowanych metodami: torowo-uranową, termoluminescencji, radiowęgla i ESR.  Question of the age and glaciers extent during the last glaciation (Vistulian) in the Polish Tatra Mts Geologic and geomorphologic investigations of relief and Quaternary deposits were carried through in the selected areas of the Polish part of High Tatra Mts (J. Dzierżek et al., 1982a, b, 1986, 1987; J. Dzierżek, J. Nitychoruk, 1986, 1987) as well as in the Western Tatra Mts (L. Lindner, 1985; J. Butrym et al., 1990). These studies together with the absolute datings of deposits by radiocarbon method (B. Wicik, 1979; P. Libelt, 1988) and thermoluminescence method (W. Stańska-Prószynska, M. Prószyliski, 1984; H. Prószynska-Bordas et al., 1988; J. Butrym et al., 1990) caused ground for a new opinion about the age and the extents of glaciers during stages and phases of the Last Glaciation in the Polish Tatra Mts (Fig. 1-4). Each stage and phase of glaciers development was separated by the interstage or interphase warmings which were conductive to groving of the carbonate sinters in the caves. These sinters were dated by U/Th method (J. Glazek, 1984) as well as by thermoluminescence, radiocarbon and ESR methods (H. Hercman et al., 1987; A. Bluszcz et al., 1988). All above mentioned data together with results of the litho- and biostratigraphical studies over the sediments of postglacial lakes (B. Wicik, 1979; B. Marciniak, A. Cieśla, 1983; K.M. Krupinski, 1984; K. Szeroczyńska, 1984; K. Więckowski, 1984) proved that the older development of glaciers of the Last Glaciation in the Polish Tatra Mts occurred at 60,000-40,000 years BP, during the Bystra Stage. This stage is an equivalent of the Świecie Stage in the Polish Lowland (Fig. 2). During the Bystra Stage glaciers reached locally their greatest extent on the northern side of the Tatra Mts (Fig. 3). This stage was preceded by the warming of the I Interstage ofMiętusia Cave, when sinters dated for 70,000 ± 35,000 to 60,000 ± 20,000 years BP, grew (Fig. 2). The younger development of glaciers in the Polish Tatra Mts during the Last Glaciation occurred at about 32,000 ± 10,000 years BP. This glacial episode called Białka Stage is correlated with the Main Stage in the Polish Lowland (Fig. 2). Development of glaciers during the both Bystra and Białka stages was divided by the warming of the II Interstage of Miętusia Cave. Carbonate sinters dated for 40,000± 12,000 to 35,000± 1500 years BP also grew then (Fig. 2). Within the Białka Stage four phases of glaciers development separated by three interphases were distinguished (Fig. 2). During the Hurkotne Phase (the oldest one) glaciers in the Polish Tatra Mts. reached their maximum extent (Fig. 3, 4). During the Łysa Polana Phase, which correspond with the Leszno-Poznań phases in the Polish Lowland, glaciers reached the line (Fig. 4) recognized by E. Romer (1929), B. Halicki (1930), M. Klimaszewski (1967, 1988), J. Dzierżek et al. (1986, 1987) as the record of their greatest extent. During the Włosienica Phase correlated with the Pomeranian Phase in the Polish Lowland, extent of glaciers was smaller (Fig. 4), whereas during the Dolina Pięciu Stawów Polskich Phase - an equivalent of the Gardno Phase on the Polish Lowland, glaciers occurred only in the uppermost parts of valleys (Fig. 4). Glaciers in the Polish part of Tatra Mts disappeared probably in the Older Holocene, at the turn of Boreal and Atlantic Period. During the Little Ice Age (600-100 years BP) only col rock glaciers and pathes (residual now) of cirque glaciers developed.