CARADOCIAN AND ASHGILLIAN BRACHIOPODS OF THE KOTEL’NY ISLAND AND THEIR CORRELATION VALUE (UPPER ORDOVICIAN, ARCTIC REGION)

N. P. Kulkov, M. K. Danukalova

The Upper Ordovician brachiopods from the upper Malodiring-Ayan and Tertyutekh formations on the Kotel’ny Island were studied. Eleven species pertaining to nine genera and eight families were described. Most of them are species characterized by wide geographical and relatively scarce stratigraphic occurrence. This was a reliable proof of the Caradocian and Ashgillian ages of the formations and became a background for a wide interregional biostratigraphic correlation of coeval deposits. The Hirnantian substage analogs were discovered in the Kotel’ny Island and Siberian Platform sections for the first time. The study results have proven reliability of the British stratigraphic chart of the Ordovician system and inadequacy of the newest stratigraphic chart compiled from mixed-up stages “discovered” in different continents

Key words: Ordovician, Silurian, stage, formation, brachiopods, stratigraphic correlation.

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