Die Paläogeographie und Fazien der kambrischen Ablagerungen im Bereich der osteuropäischen Plattform

Cambrian deposits composed of marine ‒ terrigenous sediments having paleontologic characteristics are widely distributed throughout the Baltic region (Tables 1 and 2). The thickness of the Cambrian deposits exeed 250 m. The majority of the Cambrian deposits (of the Mobergella, Holmia and Protolenus zones) occur in western Baltic regions (Fig. 1). The paleogeographic map shows three lithological facies zones: 1) with up to 85 % sandstones and up to 15 % aleurolites; 2) up to 30‒60 % sandstones, 5‒40 % aleurolites and 5‒20 % clays; 3) up to 65 % clays, 20‒35 % aleurolites and 5‒15 % sandstones. The deposits may be as much as 100 m thick (Zemyte ‒ 80 m, Jagodnaja ‒ 107 m). The Middle Cambrian deposits (of the Paradoxides oelandicus and P. paradoxissimus zones) are distributed in the western and central Baltic regions (Fig. 2). Four lithological facies zones can be distinguished on the paleogeographic map: 1) with up to 95 % sandstones and 5‒15 % aleurolites; 2) up to 50 % sandstones, 5‒30 % aleurolites and 5‒15 % clays; 3) up to 50 % clays, 5‒25 % aleurolites and 5‒15 % sandstones; 4) clays up to 65 %, 25‒35 % aleurolites and 5‒10 % sandstones. Rocks containing up to 3‒5 % carbonates have been found in some drill holes. The deposits are up to 150 m thick (Zemyte ‒ 109 m, Jagodnaja ‒ 159 m)