Development of the late glacial Baltic basin and the succession of vegetation cover as revealed at Palaeolake Haljala, northern Estonia

Abstract

The 4.5 m thick Haljala sequence in North Estonia was studied to provide information on palaeoenvironmental changes between 13 800 and 11 300 cal yr BP. Late glacial environmental history of North Estonia was reconstructed using AMS-dated pollen record, sediment composition, plant macrofossils, and ostracods. The obtained data show environmental fluctuations that are linked to the climate shifts of the Last Termination in the North Atlantic region. Decrease in the arboreal pollen accumulation rate around 13 700-13 600 and 13 300-13 100 cal yr BP refers to short deterioration of climate within the Allerød Interstadial and has been correlated with the cooling of the Greenland Interstadial GI-1c and GI-1b events, respectively. Between 13 100 and 12 850 cal yr BP the pollen accumulation rate of trees, shrubs, and herb as well as organic matter increased, indicating short-term climate amelioration and establishment of pine-birch woods. This change has been correlated with the GI-1a event. Climate deterioration during the Younger Dryas (GS-1) was inferred from the reduction of tree pollen and flourishing of cold-tolerant species, such as Artemisia, Chenopodiaceae, and Cyperaceae. New data show that ice cover of the Pandivere Upland started to perish already about 13 800 cal yr BP.

Palaeoclimate inferred from δ18O and palaeobotanical indicators in freshwater tufa of Lake Äntu Sinijärv, Estonia

“…The evaporation in this region during ice-free periods varies from 575 to 600 mm/yr (Arold 2005). The area of Äntu Sinijärv was deglaciated from the Late Weichselian glaciation already around 13,800 cal yr BP (Saarse et al 2009), This data is also supported by the results of Kalm (2006) and Rosentau et al (2007), indicating dry land conditions in the Pandivere Upland area already before 13,300 cal yr BP. The average water level in the lake is approximately 94.6 m a.s.l., the surface area is 2.4 ha and maximum depth 7.3 m, shores are paludal and the bottom is covered with lacustrine lime (Saarse and Liiva 1995).…”

“…13,300 cal yr BP, which is 500 years later than suggested by Saarse et al (2009). The gyttja layer ranges over a 1,500-year interval before it is replaced by pure freshwater tufa and includes abrupt mineral matter inflow (ca.…”

“…Deposition of freshwater tufa began ca. 11,800 cal yr BP which is ~2,000 years after the area was deglaciated at 13,800 cal yr BP (Saarse et al 2009) and 1,000 years later than indicated by Sohar and Kalm (2008). According to Männil (1967), freshwater tufa precipitation in the Pandivere area started at ca.…”

Deglaciation chronology of the Pandivere and Palivere ice-marginal zones in Estonia

“…The AMS 14 C dates con firm that sed i men ta tion in these bas ins started no later than 356 Leili Saarse, Atko Heinsalu and Siim Veski 13,800 cal yr BP ( Fig. 5; Saarse et al, 2009;Amon and Saarse, 2010), sup port ing the idea that the study ar eas were free of ice by that time. Our dates con form to varve counts in the Pärnu area, and they place the stag na tion of the Pandivere zone within ca.…”

“…The im ple men ta tion of the AMS 14 C method, which sig nif i cantly re duces the quan tity of car bon re quired for ob tain ing ra dio car bon dates, opened up new pos sibil i ties for dat ing ter res trial macrofossils pre served in minerogenic Late Gla cial sed i ments. Dur ing the last de cade, this method was widely used in the Bal tic re gion for con strain ing Late Gla cial chronostratigraphy and ice re ces sion chro nol ogy (StanèikaitÅ et al, 2002(StanèikaitÅ et al, , 2004(StanèikaitÅ et al, , 2008Láugas et al, 2002;Heikkilä et al, 2009;Saarse et al, 2009;Amon and Saarse, 2010;Kihno et al, 2011;Amon et al, 2012). How ever, it should be taken into con sid er ation that ra dio car bon ages ob tained from the basal sed i ment lay ers that are pre served in lake de pres sions do not di rectly date the deglaciation but merely in di cate the min imum time when the area be came ice-free.…”