Pre-Devonian landscape of the Baltic Oil-Shale Basin, NW of the Russian Platform

Abstract: The erosional relief of Ordovician and Silurian deposits in Estonia was developed during the continental period in late Silurian d early middle Devonian times. The uplift of the area and marine regression were induced by compressional tectonics in the continental interior elated to the closure of the Iapetus and Tornqvist Oceans. In the northern part of the Baltic sedimentary basin (Estonia), on the gentle southerly dipping slope between the Fennoscandian Shield (Finland) and Baltic Syneclise (Latvia), a pre-Devonian, slightly rugged erosional relief with few cuesta was developed. The pre-Devonian erosional landforms- hills, depressions and escarpments reaching 150m in height- were probably buried under the Devonian deposits and then partly re-exposed by pre-Quaternary erosion. These landforms are described in detail using data from several thousands of cores drilled in the course of oil-shale and phosphorite exploration and mining. Erosional relief on Ordovician and Silurian deposits in the northwest of the East European Craton was developed during the continental period of exposure in the late Silurian an