Water-level changes and palaeogeography of proglacial lakes in eastern Estonia: synthesis of data from the Saadjärve Drumlin Field area

We studied the water-level changes and palaeogeography of Late Weichselian proglacial lakes in eastern Estonia using the shoreline and sediment distribution proxies from the Saadjärve Drumlin Field area together with the geomorphological correlation and GIS-based palaeoreconstructions. Our results show that about 14.0-13.8 cal. kyr BP Glacial Lake Peipsi inundated large areas of the Saadjärve Drumlin Field, Emajõgi River valley and reached the Lake Võrtsjärv basin. In the Saadjärve Drumlin Field area this is reflected in the formation of the highest shoreline and the corresponding rather short period (up to 63 years) of varved clay accumulation. The highest shoreline determined in the Saadjärve Drumlin Field is correlated with the valley terraces in southeastern Estonia, which reflect the water level in Glacial Lake Peipsi and the proglacial lake in the Võrtsjärv basin. The study suggests settling of glacial varved clay in the deepest inter-drumlin basins at the critical (minimal) water depths of about 15-20 m. The proglacial conditions lasted in the Saadjärve Drumlin Field for about 150 years and were interrupted due to the isolation of the lakes from proglacial bodies of water in the Peipsi and Võrtsjärv basins after the formation of the second highest shoreline. In the bottom sediments this isolation is marked by the transition from the laminated sediments to the massive silt interval. The results show that about 14.0-13.8 cal. kyr BP the connection route between Glacial Lake Peipsi and proglacial Lake Strenči, northern Latvia, shifted from the Võhandu-Hargla valley to the Väike-Emajõgi valley and the strait between Glacial Lake Peipsi and large Lake Privalday in northwestern Russia was closed

Geological settings of the protected Selisoo mire (northeastern Estonia) threatened by oil shale mining

The protected Selisoo mire in northeastern Estonia is located above valuable oil shale resources, partly in the permitted mining area. We describe in detail the geomorphology and geological setting of the mire to understand the natural preconditions for its formation, development and preservation. We used the LiDAR-based digital elevation model for relief analysis, mapped the peat thickness with ground-penetrating radar and described the Quaternary cover through corings. Ridges, oriented perpendicular to the generally southward-sloping terrain, and shallow depressions at the surface of mineral soil have influenced mire formation and its spatio-temporal dynamics. The Quaternary cover under the mire is thin and highly variable. Therefore the mire is hydro­geologically insufficiently isolated from the limestone bedrock that is drained by the nearby oil shale mine and consequently the mining activities approaching the mire may have a negative influence on the wetland and proposed Natura 2000 site. Natura 2000 type wetlands, both protected or currently outside the nature reserves, cover a significant portion of the prospective oil shale mining areas. The distribution and resilience of those sites may significantly influence further utilization of oil shale resources

Thickness distribution of quaternary deposits in the formerly glaciated part of the East European plain

<p>A thickness map of Quaternary deposits in the south-eastern sector of the last Scandinavian Ice Sheet (SIS) and in areas of Middle Pleistocene Moscow (Warthe) and the Dniepr (Drente) stages of the Late Saalian glaciation on the East European Plain is presented (<a href="http://dx.doi.org/10.1080/17445647.2014.954646" target="_blank">Main Map</a>). The map of the thickness and related statistics of the Quaternary deposits were calculated from the difference between the current digital terrain model and the bedrock surface topography model. The distribution of Quaternary deposits shows that 29% of the mapped territory has sediments less than 25 m thick, 16% more than 100 m and 1.2% more than 200 m. Within the SIS area, the thickness of sediments in the southern sector exceeds threefold the sediment thickness in the eastern flank. This difference is attributed to the bedrock depression in the south-east of the Baltic Syneclise rather than to glacial dynamics. The calculated average thickness of the sediments within the SIS area is ca 50 m, in the formerly glaciated area outside the LGM it is ca 61 m and outside the glaciated area ca 14 m. Our study confirms that, in formerly glaciated areas, the spatial distribution of sediments did amplify the differences in glacial bed topography with the exception of the southern and eastern flanks of the Moscow glaciation area where exceptionally thick Quaternary deposits have inverted bedrock depressions into elevated areas in recent terrain. We suggest that the map presented improves existing knowledge of this area by adding detail and thus contributing to the on-going development of numerical ice-sheet models.</p

Sample details on OSL data for aeolian sediments in north-eastern part of European Sand Belt

A compilation of previously published and unpublished absolute age (OSL and TL) determinations of aeolian sediments from the north-eastern part of European Sand Belt. Contains age, error, sampling depth, location etc. and a reference to data source. Coordinates of sampling locations for contemporary publications are taken from field observations (GPS), but older ones - published schematic maps. Data set is created according to schema of DATED-1 database (https://doi.org/10.1594/PANGAEA.848117)

Late-Holocene relative sea-level changes and palaeoenvironment of the Pre-Viking Age ship burials in Salme, Saaremaa Island, eastern Baltic Sea

Two unique Pre-Viking Age ship burials were found from Salme village, Saaremaa Island, eastern Baltic Sea, containing remains of seven men in the smaller and 34 men in the larger ship. According to the archaeological interpretations, these ships belonged to a viking crew possibly from the Stockholm-Mälaren region, eastern Sweden. Geoarchaeological research was conducted in the area to reconstruct Late-Holocene relative sea-level (RSL) changes and shoreline displacement to provide environmental context to these burials. In this paper we present a Late-Holocene shore displacement curve for the Saaremaa Island and GIS-based palaeogeographic reconstructions for the Salme area. The curve shows an almost linear RSL fall from 5.5 to 0.8 m a.s.l. between 1000 BC and 1300 AD with an average rate of 2 mm/year. A slowdown in regression may be attributed to accelerated sea-level rise after the Little Ice Age and during the industrial period, being consistent with the tide-gauge measurements from the 20th century. Palaeogeographic reconstructions indicate the existence of a strait in the Salme area during the burial of the ships. The eastern part of the strait with water depth up to 2.8 m was about 80–100 m wide. The relatively steep and wind-protected shores in that part of the strait were probably the best places in the area for landing the viking ships. According to sedimentological evidence and diatom data, the narrowing of Salme palaeostrait occurred between 1270 and 1300 AD. Salme I and II ships were buried at 650–770 AD into the sandy-gravelly coastal deposits which had accumulated there in the open coastal zone about 710–450 years earlier. Reconstructions show that the ships were located about 2–2.5 m above coeval sea level and more than 100 m from the coastline. Thus, both ships were probably moved from the shore to the higher ground for burial

Rapid Magnetic Susceptibility Characterization of Coastal Morphosedimentary Units at Two Insular Strandplains in Estonia

Coastal archives of changing hydrometeorological conditions include mineralogical anomalies, such as heavy-mineral concentrations (HMCs) of variable thickness and intensity, which contain varying ferrimagnetic (e.g., magnetite) fractions. As an effective alternative to laborious mineralogical and granulometric analysis, we present the first set of bulk-volume low-field magnetic susceptibility (MS) databases from beach and dune lithosomes in the Western Estonian archipelago: Harilaid cuspate foreland (westernmost Saaremaa Island) and Tahkuna strandplain (northernmost Hiiumaa Island). Readings were conducted both in situ from trench walls and on core subsamples. At the Tahkuna site, late Holocene beach ridges reveal substantially lower values: quartz-dominated dune sequences grade from 5&ndash;20 &mu;SI downward to diamagnetically dominated (&minus;1&ndash;7 &mu;SI) beach facies. Values are higher (20&ndash;140 &mu;SI) in historically reactivated parabolic dunes that are encroaching southward over the strandplain. At the Harilaid site, four beach dune ridges (height: 2&ndash;3 m) that span the past 250&ndash;300 years show a general increase in mean MS from 320&ndash;850 &mu;SI with decreasing age, with peaks of 1000&ndash;2000 &mu;SI below the dune crests (depth: ~0.3&ndash;0.6 m) likely related to contemporary wind acceleration during ridge aggradation. The highest mineralogical anomalies range from 2000&ndash;5500 &mu;SI in the historic dune sections and exceed 8000 &mu;SI along the actively eroding upper-berm segments, typical of HMCs generated by moderate storms. MS anomalies are likely correlated with high-amplitude electromagnetic signal responses in georadar records and provide useful information for optical luminescence sampling strategies. Our study demonstrates that magnetic susceptibility trends provide a useful means of rapidly assessing relative temporal changes in overall wave/wind climates, help identify and correlate discrete anomalies related to extreme events, serve as local beach/dune boundary indicators, and represent potentially quantifiable paleo-energy indices

Holocene relative shore-level changes and development of the Ģipka lagoon in the western Gulf of Riga

Holocene relative shore-level changes and development of the G ipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho-, biostratigraphical and chronological data with remote sensing and geophysical data. The results show the development of the G ipka basin from the Ancylus Lake/Initial Litorina Sea coastal zone (before c. 9.1 cal. ka BP) to coastal fen (c. 9.1 to 8.4 cal. ka BP) and gradual development of the Litorina Sea lagoon (c. 8.4 to 4.8 cal. ka BP) and its transition to a freshwater coastal lake (c. 4.8 to 4.6 cal. ka BP), fen (c. 4.6 to 4.2 cal. ka BP), and river floodplain (since c. 4.2 cal. ka BP). The highest shorelines of the Ancylus Lake and Litorina Sea were mapped at an elevation of 12–11 and 9 m a.s.l., respectively. A new relative shore level (RSL) curve for the western Gulf of Riga was constructed based on RSL data from the G ipka area and from nearby Ruhnu Island studied earlier. The reconstruction shows that the beginning of the lastmarine transgressionin the western Gulf of Riga started at c. 8.4 cal. ka BP, and concurred with the 1.9 m RSL rise event recorded from the North Sea basin. Diatom analysis results indicate the existence of the G ipka lagoon between c. 7.7 and 4.8 cal. ka BP, with the highest salinityc. 6.1 cal. ka BP. During the existence of the brackish lagoon, settlement sites of the Neolithic hunter–gatherer groups existed on the shores of the lagoon in the period c. 6.0 to 5.0 cal. ka BP