Silurian stratigraphy of East Siberia

This paper is the first report on the Silurian stratigraphy in East Siberia (Siberian Platform and Taimyr Peninsula). Stratigraphic demarcation for the Silurian system is based on temporal sets of stratigraphic subdivisions. The authors distinguish five subregions and 15 districts: Middendorf (North Taimyr subregion); Norilsk, Turukhansk, and Igarka (North Yenisei subregion); Kochumdek, Vorogovo, South Taimyr, Ledyanka, Maimecha, Moiero, Morkoka, and Vilyuy (Tunguska subregion); Nyuya-Berezovo (district and subregion); and Ilim and Balturino (Irkutsk subregion). They establish six regional stratigraphic subdivisions - horizons (regional stages): Moyerocanian (Rhuddanian - Lower Aeronian), Khaastyrian (Middle-Upper Aeronian), Agidyian (Telychian), Khakomaian (Wenlock), Tukalian (Gorstian), and Postnichian (Ludfordian-Pridoli), as well as 13 subhorizons and 54 regional chronozones, which are compared with corresponding global units. For paleontological justification of global and regional chronozones, global and regional biochronology is presented, which is based on the levels of appearance of diverse fauna groups in the chronozones. Each of 15 stratigraphic districts has local stratigraphic subdivisions (local series, formations, subformations, and local chronozones), and these districts are described to the subformations. The chronostratigraphic chart is first developed to regional chronozones, which are compared with global chronozones.