Pozycja geologiczna osadów plejstoceńskich z dna Bałtyku południowego datowanych metodą termoluminescencji
Abstract
GEOLOGICAL RELATIONS OF THE PLEISTOCENE DEPOSITS FROM THE SOUTHERN BALTIC BOTTOM AND THERMOLUMINESCENCE DATA
Summary
First dating of 8 samples from the Pleistocene glacial tills from Southern Baltic Sea bottom, made using the TL method, has obtained an age over 122 ka BP (7, 8) and given an assumption for further investigations. During the cartographic and prospecting works in 1984 -1988 (Fig. 1) were got cores from the Pleistocene deposits (consisted in 90% of glacial and subaqueous tills), laying under thin cover of Holocene limnic or marine sediments (Fig. 2). The TL age indexes have been settled for 69 samples from 52 core profiles (Tab. I, Fig. 2). The estimated frequency distribution of TL age indexes for 20 ka years periods is polimodal with three peaks in intervals: 130 - 150 ka, 50 - 70 ka and 10- 30 ka BP (Fig. 3). These peaks are correlable with siutable Odra and Vistula Il and III glaciations. The glacial tills of last cold period are less common as it was assumed till now. These TL indexes allow to interpret the genesis of Southern Baltic Sea bottom morphology in new way. Its considerable areas were regarded till now as uplifts of recessive morains, dated as last stages of the Vistula glaciation. According new data the broad parts of bottom are connected with baring the older glacial structures and they reflect the various resistance of glacial deposits for exaration and abrasion processes (Fig. 4).
Summary
First dating of 8 samples from the Pleistocene glacial tills from Southern Baltic Sea bottom, made using the TL method, has obtained an age over 122 ka BP (7, 8) and given an assumption for further investigations. During the cartographic and prospecting works in 1984 -1988 (Fig. 1) were got cores from the Pleistocene deposits (consisted in 90% of glacial and subaqueous tills), laying under thin cover of Holocene limnic or marine sediments (Fig. 2). The TL age indexes have been settled for 69 samples from 52 core profiles (Tab. I, Fig. 2). The estimated frequency distribution of TL age indexes for 20 ka years periods is polimodal with three peaks in intervals: 130 - 150 ka, 50 - 70 ka and 10- 30 ka BP (Fig. 3). These peaks are correlable with siutable Odra and Vistula Il and III glaciations. The glacial tills of last cold period are less common as it was assumed till now. These TL indexes allow to interpret the genesis of Southern Baltic Sea bottom morphology in new way. Its considerable areas were regarded till now as uplifts of recessive morains, dated as last stages of the Vistula glaciation. According new data the broad parts of bottom are connected with baring the older glacial structures and they reflect the various resistance of glacial deposits for exaration and abrasion processes (Fig. 4).