Bedrock relief with the basics (subdivision and thickness) of the overlying Quaternary sequence was studied by means of seismo-acoustic profiling beneath the Suur Strait in the West Estonian Archipelago. Reaching ca 15–20 m below sea level (b.s.l.) in the watershed area in the NE corner of the Gulf of Riga, the bedrock surface beneath the strait drops along two channels, divided by the islet of Kesselaid rising ca 15 m above sea level (a.s.l.), into a large depression more than 60 m b.s.l. in the interior of the Väinameri. A similar setting indicates that the low-lying bedrock surface between the Estonian mainland and the islands of Muhu and Saaremaa was formed by combining erosions of preglacial river(s) and Pleistocene glaciers. The large depression NW of the islet of Kesselaid possibly represents a section of an east-west running preglacial river, heavily reworked by Pleistocene glaciers. Although supported by preliminary data from the Soela Strait, the latter opinion still needs additional profiling between the islands of Hiiumaa and Saaremaa. The thickness of the Quaternary sequence around the strait follows the general height and ruggedness of the bedrock surface; it is occasionally missing in the nearshore bedrock plateaus (submarine alvars) and reaches ca 50 m in the depression NW of Kesselaid.
Bennett, M. R. and Glasser, N. F. 2009. Glacial Geology: Ice Sheets and Landforms. 2nd ed. Wiley-Blackwell, Oxford.
Kalm, V., Tsurylnikov, A., Hang, T., Tuuling, I. and Flodén, T. 2006. Late Weichselian and Holocene sediments and their acoustic signatures in the northeastern part of the Gulf of Riga. Baltica, 19(2), 51–57.
Karukäpp, R. 2004. Late-Glacial ice streams of the southeastern sector of the Scandinavian ice sheet and the asymmetry of its landforms. Baltica, 17(1), 41–48.
Kvasov, D. D. 1975. Позднечетвертичная история крупных озер и внутренних морей Восточной Европы (Late Quaternary history of the large inland seas and lakes in the Eastern Europe). Наука, Ленинград (in Russian).
Lutt, J. 1985. Донные осадки Вяйнамери (Bottom sediments of the Väinameri). Valgus, Tallinn (in Russian).
Lutt, J. and Raukas, A. (eds). 1993. Eesti šelfi geoloogia (Geology of the Estonian shelf). Eesti Geoloogia Selts, Tallinn (in Estonian with English summary).
Overeem, I., Weltje, G. J., Bishop-Kay, C. and Kroonenberg, S. B. 2001. The late Cenozoic Eridanos delta system in the Southern North Sea Basin: a climate signal in sediment supply? Basin Research, 13(3), 293–312
https://doi.org/10.1046/j.1365-2117.2001.00151.x
Tammekann, A. 1940. The Baltic Glint. A Geomorphological Study. Eesti Loodusteaduste Arhiiv. Series I, XI(3–4), Tartu.
Tavast, E. and Raukas, A. 1982. Рельеф коренных пород Эстонии (The bedrock relief of Estonia). Valgus, Tallinn (in Russian with English summary).
Tsyrulnikov, A., Tuuling, I. and Hang, T. 2008. Streamlined topographical features on and offshore the Gulf of Riga as evidence of Late Weichselian glacial dynamics. Geological Quarterly, 52(1), 81–89.
Tsyrulnikov, A., Tuuling, I., Kalm, V., Hang, T. and Flodén, T. 2012. Late Weichselian and Holocene seismostratigraphy and depositional history of the Gulf of Riga, NE Baltic Sea. Boreas, 41(4), 673–689.
https://doi.org/10.1111/j.1502-3885.2012.00257.x
Tuuling, I. 2017. Palaeozoic rocks structure versus Cenozoic cuesta relief along the Baltic Shield–East European Platform transect. Geological Quarterly, 61(2), 396−412.
https://doi.org/10.7306/gq.1342
Tuuling, I. and Flodén, T. 2001. Structure and relief of the bedrock sequence of the northern Baltic Proper. GFF, 123, 35−49.
https://doi.org/10.1080/11035890101231035
Tuuling, I. and Flodén, T. 2016. The Baltic Klint beneath the central Baltic Sea and its comparison with the North Estonian Klint. Geomorphology, 263, 1−18.
https://doi.org/10.1016/j.geomorph.2016.03.030
