Comprehensive zonal subdivisions of Siberian Jurassic and their significance for Circum-Arctic correlations

Abstract

We show the present state of the set of parallel zonal scales for the Siberian Jurassic, based on various fossil groups, and the principles of their construction. We discuss the significance of Siberian biostratigraphic scales for the Boreal zonal standard of the Jurassic units. The stratotype region for this standard must have a typical Boreal (Arctic rather than mixed) fauna. A possible candidate is Siberia (and the Arctic biochorema), which is located in the center of the Panboreal Superrealm, where the set of interrelated scales for various fossil groups is the most complete. The set of parallel zonal scales for the Siberian Jurassic is efficient for the subdivision and correlation of Jurassic units in various Arctic regions (Barents Sea shelf, northeastern Russia, Arctic Alaska, Arctic Canada).

Jurassic and Cretaceous stratigraphy of the Anabar area (Arctic Siberia, Laptev Sea coast) and the Boreal zonal standard

“…Detailed review of the ammonite zonal scale, used for the division and correlation of Jurassic sediments in Russian boreal and subboreal regions, are given in several recent publications Sei et al, 2006;Shurygin et al, 2011;Zakharov et al, 2010;Zhamoida and Petrov, 2008). We will focus on the latest modifications proposed for this scale.…”

“…10). As practice shows, the bivalve scale developed for this interval permits interregional correlations and accurate calibration of Arctic sections of Russia and other countries (Shurygin, 2005;Shurygin et al, 2000Shurygin et al, , 2011.…”

“…It should be noted that the stratotypes of zones from the scales based on different groups of fauna and flora were located in different areas of the Boreal Realm. Further studies were aimed at the improvement and validation of the components of the Boreal zonal standard for the Jurassic and Cretaceous (Baraboshkin, 2004;Dzyuba, 2004Dzyuba, , 2012Knyazev et al, 2003;Mickey et al, 1998;Nikitenko, 2009;Nikitenko and Mickey, 2004;Shurygin, 2005;Shurygin et al, 2000Shurygin et al, , 2011Zakharov et al, 2005;Zhamoida and Petrov, 2008). In addition, some zones established in the sections of the East European Platform (ecotone region) with a mixed Boreal-Peri-Tethyan fauna of ammonites were also proposed as the Boreal zonal standard (Zakharov et al, 2005;Zhamoida and Petrov, 2008).…”

“…Thus, the Arctic should be considered as the stratotype region, because the Jurassic-Cretaceous Arctic biochorema, characterized by a typical Boreal (Arctic) rather than mixed (ecotone) fauna, was located in this region. Therefore, Siberia located in the center of the Panboreal Superrealm and characterized by the most complete set of calibrated scales on different fossil groups can be regarded as a stratotype region for Boreal scales of the Jurassic and most parts of the Lower and Upper Cretaceous Shurygin et al, 2011).…”

Callovian and Upper Jurassic foraminiferal and ammonite biostratigraphy of the Shaim petroleum region (West Siberia)

“…The Callovian-Upper Jurassic biostratigraphic subdivision for West Siberia is an integration of zonal scales, which were correlated with each other based on of different macro-and microfossils, such as ammonites, belemnites, bivalves, foraminifers, ostracods, and plant remains (Gurari, 2004;Nikitenko, 2009;Nikitenko et al, 2013;Shurygin et al, 2000Shurygin et al, , 2011. Newly established zonal scales of West Siberia reflect the considerable level of stratigraphic knowledge of the region that has been extensively drilled and sampled for paleontological studies and provided the increased number of reliably identified fossils.…”