Ancient buried valleys in the city of Tallinn and adjacent area

Abstract

The distribution, morphology, fillings, and origin of buried valleys are discussed. The direction of the valleys varies from NW to NE. Within the Viru-Harju Plateau the valleys have a more or less symmetric profile, but asymmetric profiles are dominating in the pre-klint area. They are mainly filled with glacial (till), glaciofluvial (sand, gravel, and pebbles), glaciolacustrine (varved clay), and marine (fine-grained sand) deposits. The Tallinn valley with its tributary valleys (Saku and Sausti) and foreklint branches (Harku, Lilleküla, and Kadriorg) looks like a river system. The fore-klint branches extend over 20 km in the Gulf of Finland. They are probably tributaries of the ancient river Pra-Neva. Most likely, the formation of valleys was continuous, starting from pre-Quaternary river erosion, and was sculptured by variable processes during the ice ages and influenced by flowing water during the interglacial periods.

Preglacial geomorphology of the northern Baltic Lowland and the Valdai Hills, north-western Russia

“…This database was used during compilation of hypsometric map of the pre-Quaternary sediments surface with 25 m interval isolines. Existing schemes of the preQuaternary surface structure from the above mentioned and published resources were considered during compilation of this map and the preglacial river network reconstruction (Malakhovsky & Markov, 1969;Kvasov, 1975;Gibbard, 1988;Grigelis, 1991;Auslender, 1998;Vaher et al 2010).…”

“…in Lake Ilmen depression) with V-shaped cross-sections (Verbitskiy et al 2007). We assume that the preglacial river erosion was the main factor of deep incisions formation, albeit their genesis could be explained in different ways (see Malakhovskiy & Fedorov, 1984;Malakhovskiy, 1995;Rattas, 2007;Vaher et al, 2010).…”

Geological and environmental pre-conditions for utilisation of the Maardu granite deposit, northern Estonia

“…Filtration properties of the aquifer are consistently similar: lateral K prevailingly 1-3 m/d and specific yield of wells 0.1-0.4 l/s×m. Exceptionally, on the territory of the Mähe buried valley over the Lake Maardu (Miidel et al 2010) and in the Maardu opencast K reaches up to 10 m/d. The groundwater of HCO 3 Ca-Mg type is fresh (0.3-0.4 g/l); when mixed with contaminated mine water it is of HCO 3 SO 4 Ca-Mg type and has TDS 0.5-1 g/l, and in abandoned workings even of SO 4 HCO 3 CaMg type and with TDS 2 g/l.…”

Quaternary deposits and weathered bedrock material as a source of dangerous radon emissions in Estonia

“…The westeast oriented North Estonian Klint 1 , up to 55.6 m in height (Suuroja, 2006), and deep ancient valleys cutting into the sedimentary bedrock (Miidel et al, 2006;Raukas & Tavast, 1987;Vaher et al, 2010) are the most remarkable elements of the bedrock.…”