Pietų Lietuvos Dubičių prieledyninio ežero paleogeografinė raida poledynmečiu

• Main Authors: Švedas, Kęstutis, Česnulevičius, Algimantas
• Format: Article in Journal/Newspaper
• Language: Lithuanian; English
• Published: 2009
• Subjects: Glaciolacustrine; Thermokarst; Geomorfologic method; Lithology method; Carthographic method; Dubičiai basin; Ūla river
• Online Access: http://lmavb.lvb.lt/LMAVB:ELABAPDB5864927&prefLang=en_US

The Dubičiai glaciofluvial basin was investigated by geomorphological, lithological and cartographic methods. These methods allowed estimating the water levels of this basin in the past. The stable water level created favourable conditions for sedimentation of sapropel, freshwater limestone, shells and plant residuals. Terrigenous sediments of diferent composition and origin accumulated in the shallow litoral zone. Formation of glaciolacustrine basin and its sedimentation conditions were determined based on the data about terrain deglaciation. The Dubičiai basin has some glaciolacustrine terraces, which formed in the Frankfurt Stage, Dryas-Allerød, Boreal-Allerød and Sub-Atlantic. The latest drainage stage goes back to 1958-1959 when a drainage project of vast dimension was implemented. An intensive relief transformation took place at the end of the Late Pleistocene and in the Early Holocene. The most marked transformations of relief were entailed by thermokarst processes, which started in Allerød and continued through Boreal. At the beginning of Pre-Boreal, air temperatures and humidity were increasing. The warmer climate created good conditions for peat, gytia and freshwater limestone accumulation. The latest stage of Dubičiai basin began in the middle of the 20th century. In 50 years, the area of the basin has decreased 10-fold: from 221 ha in 1850 to 20 ha in 1900. In the first half of the 20th century, the Ūla River deepened its longitudinal profile. This entailed capture processes: the upper part of the Katra River was joined to the Ūla catchment. This catchment transformation predetermined the drainage of the shallow lakes Matarai, Pelesa and Duba.