Gryguc, G., Kisielienė, D., Stančikaitė, M., Šeirienė, V., Skuratovič, Ž., Vaitkevičius, V., Gaidamavičius, A.
Holocene sediment record from Briaunis palaeolake, Eastern
Lithuania: history of sedimentary environment and vegetation dynamics
This paper presents new data describing the Holocene
environmental history of the Briaunis palaeolake, Eastern Lithuania. Shortly
before 9600 cal yr BP, sedimentation began in an oligotrophic deep-water basin,
whereas the Early Holocene instability of the environmental regime caused the
influx of detrital sediment into the basin. A birch forest dominated in the
surrounding landscapes, and at ca. 9600 cal yr BP, the spread of Ulmus, Alnus,
Populus and Corylus began, suggesting a short-lived climatic amelioration. A
subsequent drop of the water table and increasing influx of the terrigenous
material continued from 9600 to 9300–9200 cal yr BP. The ensuing climatic
stability caused the formation of a deciduous forest and the regional spread of
Picea. Some instability, i.e. a decline in the thermophilous species, as well
as the appearance of boreal and northern alpine diatoms, could be associated
with the so-called “8.2 ka event”. This reversal was followed by amelioration
and prospering of the water plants typical of the Holocene climatic optimum
from 7900 to 7200–7100 cal yr BP. At aproximatelly 6600–6500 cal yr BP, a small
rise of the water table was documented and bog-forming processes dominated
until ca. 3600–3400 cal yr BP, when a small-scale deepening of the basin
occured.