Boreal Toarcian Biochronological Zonation by Bivalves of the Genus <i>Meleagrinella</i> Whitfield, 1885

Abstract

Based on the chronological sequence of species of the bivalve genus Meleagrinella Whitfield, 1885 (family Oxytomidae Ichikawa, 1958) established in the Toarcian deposits of Northeast Russia, Eastern Siberia, and South Germany, a biochronological scale of the Lower Toarcian is proposed. Three oxytozones corresponding to Boreal ammonite zones are established: Meleagrinella golberti Oxytozone = Tiltoniceras antiquum and Harpoceras falciferum zones; Meleagrinella substriata Oxytozone = Dactylioceras commune Zone; Meleagrinella prima Oxytozone = Zugodactylites braunianus and Pseudolioceras compactile zones. Using the proposed zonation, an interregional correlation of sections of the Lower Toarcian of the North-East of Russia (Astronomicheskaya, Saturn, Brodnaya, Start rivers), Eastern Siberia (Anabar Bay, Markha, Tyung, Vilyui, Kelimyar, Motorchuna, wells of the Vilyui syneclise) and South Germany (the Ludwig Canal) is performed.