Palaeogeographic reconstruction of proglacial lakes in Estonia

Abstract

This paper describes a Geographical Information System (GIS)-based palaeogeographic reconstruction of the development of proglacial lakes formed during deglaciation in Estonia, and examines their common features and relations with the Baltic Ice Lake. Ice marginal positions, interpolated proglacial lake water levels and a digital terrain model were used to reconstruct the spatial distribution and bathymetry of the proglacial lakes. Our results suggest that the proglacial lakes formed a bay of the Baltic Ice Lake after the halt at the Pandivere ÁNeva ice margin about 13.3 cal. kyr BP. Shoreline reconstruction suggests that two major proglacial lake systems, one in eastern and the other in western Estonia, were connected via a strait and thus had identical water levels. The water budget calculations show that the strait was able to transfer a water volume several times greater than the melting glacier could produce. As this strait compensated for the water level difference between the two lake parts, the subsequent further merging in north Estonia did not result in catastrophic drainage, as has been proposed.

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

“…The isolation age of Palaeolake Haljala dates proglacial Lake Kemba to around 13 100 cal yr BP, which agrees with an earlier estimation of 13 150 cal yr BP by Vassiljev et al (2005), but is somewhat older than the date (12 800 cal yr BP) proposed by Rosentau et al (2007). Two 10 Be dates from boulders 20 and 30 km west and northwest from Haljala correspond to the approximate level of proglacial Lake Kemba, 12 480 ± 920 (EST-8) and 12 520 ± 890 (EST-11; Rinter-knecht et al 2006), however, these boulders are of somewhat lower level and accordingly have younger ages.…”

Late-glacial to Holocene aeolian deposition in northeastern Europe – The timing of sedimentation at the Iisaku site (NE Estonia)

“…However, the palaeogeographical reconstruction of BIL at about 13.3 ka suggests the existence of an island located north of Lake Peipsi and separating the latter from the BIL A 2 stage (Vassiljev and Saarse, 2013). The position of the lower shoreline narrowed the connection between Lake Peipsi basin and the BIL (Rosentau et al, 2007) increasing the size of the island. The luminescence age of the sample (sample 123071; Table 1) taken from the middle of the leeward slope could place the Iisaku area within this hypothesised island.…”

Pollen, diatom and plant macrofossil assemblages indicate a low water level phase of Lake Peipsi at the beginning of the Holocene

“…Shore displacement curves for the southern part of Lake Peipsi proper (Hang et al, 1995;Rosentau, 2006) display a rapid regression between 12.5 and 10.2 ka 14 C yrs BP with the minimum water level about 10.2 ka 14 C yrs BP, slightly after the last drainage event of the BIL (ca. 10.3 ka 14 C yrs BP).…”

“…9.1 ka 14 C yrs BP and was thereafter followed by a continuous rise in water level up to the present. Recent GIS-based simulations of the development of proglacial lakes in eastern Estonia (Rosentau, 2006) demonstrate that the final strait-like connection between the BIL and the Glacial Lake Peipsi ceased at the Narva River valley (Fig. 1) if the proglacial lake level was lowered to 35-32 m. a.s.l.…”