An Eemian - Middle Weichselian sequence from the Jonionys site, Southern Lithuania

• Main Authors: Satkūnas, Jonas, Grigienė, Alma, Robertsson, Ann-Marie
• Format: Article in Journal/Newspaper
• Language: Lithuanian; English
• Published: 1998
• Subjects: Eemian; Weichselian; Brörup; Odderade; Oerel; Palaeolake; Interstadials; Thermomers; Cryomer; Pollen; Chemical composition; Arctic; Ice Sheet; Tundra
• Online Access: http://lmavb.lvb.lt/LMAVB:ELABAPDB5834604&prefLang=en_US

Investigations carried out in the classical Jonionys site (Southern Lithuania) in 1994-1996 resulted in the discovery of a sequence representing the interval from the Eemian and up to Middle Weichselian. This is probably the most complete sequence known so far in south-eastern Baltic region. The Jonionys palaeolake which is a kettle hole was formed during the late-glacial phase after the recession of the Saalian ice sheet. During the Merkinė (Eemian) Interglacial and the succeeding Weichselian interstadials it had isometric shape and a diameter of 450-500 m. The kettle was filled in by clay, gyttja and silt with sandy interlayers. The pollen flora and lithological data obtained display a continuous sedimentation record representing the Eemian Interglacial, three Weichselian interstadials: Jonionys-1 (Brorup), Jonionys-2 (Odderade), Jonionys-3 (Oerel), and the cryomers separating these interstadials. The presence of a third interstadial (Jonionys-3), younger than Odderade, has been established for the first time in Lithuania, as well as in all the eastern Baltic region. The interstadials Jonionys-1 and Jonionys-2 are characterised by a vegetational succession from open shrub and herb tundra to birch and later coniferous forest with pine, spruce and larch. Jonionys-3 is characterised by birch and herbs. During the cryomers an arctic steppe existed with continental climate which is indicated by the presence of Artemisia and Chenopodiaceae. The Jonionys sequence correlates well with other sites in Lithuania and provides evidence that nonglacial environment persisted in southern and eastern Lithuania from the end of Eemian Interglacial until Late Weichselian, when the main advance of the continental ice sheet took place.