Ordovician deposits are widely represented within the Soviet Arctic. They are known in Novaya Zemlya, Vaygach Island, Pay-Khoy, Severnaya Zemlya, northern Siberian platform, New Siberian Islands, and northeastern USSR. In the western Arctic (Polar Urals-Novaya Zemlya) Ordovician deposits formed the base of the Caledonian-Hercynian cycle, and consist of a very thick variable complex of clastic and carbonate rocks.

In the central Soviet Arctic, the Ordovician is at the base of the stratigraphic column in Severnaya Zemlya, whereas on Taimyr Peninsula and the Siberian platform, it comprises a single depositional cycle with the Cambrian. The Ordovician in the region is represented by predominantly carbonate rocks reaching a thickness of 2,000 m in depressions; in the northern part of the Taimyr Peninsula it consists of graptolite-bearing clastic and carbonate rocks up to 1,000 m thick. The Ordovician of Severnaya Zemlya is represented by variegated clastic and carbonate rocks about 2,000 m thick.

Within the eastern Arctic, Ordovician deposits are a part of the fold fringe of the Kolyma massif and of the Mesozoides of northeastern Chukotsk Peninsula. Ordovician strata in the northeastern USSR consist of carbonate, clastic and carbonate, and wholly terrigenous clastic sequences. The relations with underlying rocks are uncertain there. Ordovician rock thicknesses differ markedly from place to place and reach 5,500 m in some places.

Ordovician deposits have been studies in more detail in southern Novaya Zemlya, Vaygach Island, northern Pay-Khoy, central Taimyr, in the Norilsk district, and within the limits of the folded margin of the Kolyma massif. The Ordovician of northern Novaya Zemlya, Severnaya Zemlya, and the New Siberian Islands is less well known.

However, even where Ordovician sections have been investigated comprehensively and are richly fossiliferous, the Lower-Middle Ordovician and Ordovician-Silurian boundaries are uncertain because of geologic peculiarities of the region. There is no definite solution to the Cambrian-Ordovician boundary problem. Variable sedimentary facies and diverse zoogeographic provinces make regional and interregional correlations difficult.

Nevertheless, recognition of transitional sequences in fold areas of the Soviet Arctic and the wide interregional distribution of some faunal elements during climaxes of marine transgression (late Tremadocian and middle Caradocian) permit rather definite correlations for the solution of practical biostratigraphic problems and correlation with standard sequences elsewhere.

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