N.K. Lebedeva
B.L. Nikitenko
C. Colpaert

: Revue de Micropaleontologie

The Upper Jurassic Lopsiya River sections (Nether-Polar Urals) represent the most complete stratigraphical marine sequence throughout Russia. It is characterized by a continuous succession of Kimmeridgian to Lower Volgian deposits and is defined by rich faunal associations including ammonites, belemnites, and bivalves. The Lopsiya River sections were previously studied in detail with palaeontological, lithological, and litho-geochemical purposes. Furthermore, assemblages rich in palynomorphs and foraminifers were found in the currently studied successions of the Lopsiya River sections. It results the establishment of the uppermost Oxfordian to Lower Volgian foraminiferal zones, as well as the Kimmeridgian dinoflagellate cyst zones and palynological assemblage. Then, the Upper Jurassic dinoflagellate cyst and foraminiferal biostratigraphical zonations have been calibrated against the ammonite zones. Finally, current results on the Lopsiya River sections have been compared with biostratigraphic data of the Kimmeridgian dinoflagellate cyst assemblages from northwestern Europe, Russian Platform, and Arctic Siberia. The studied foraminiferal and dinoflagellate cyst assemblages of the Upper Jurassic successions of the Lopsiya River sections hold high potential of correlations, especially for the Kimmeridgian strata.