Middle Jurassic–Lower Cretaceous Radiolarians of Koryak Segment of Circum-Pacific Fold Belt.

The geological structure was studied and the age of a number of tectonostratigraphic units in the Koryak Highlands was established for the first time. Radiolarian associations have been established that existed in various paleogeographic provinces and were combined in single tectonostratigraphic complexes. Cases of redeposition of radiolarians in siliceous rocks observed in accretionary prisms and olistostrome strata in the Koryak Highlands have been recorded. New localities of radiolarians have been discovered, which have made it possible to expand the scope of geographic distribution for some taxa. A bipolar distribution has been established for some representatives of radiolarians, first encountered in the northern hemisphere in Chukotka. The stratigraphic range of distribution for some species in the North-East of Russia and the age of a number of regional and local stratigraphic units have been clarified. A division scheme for the Middle Jurassic-Berriasian according to radiolarians for the Koryak Highlands is proposed. [ABSTRACT FROM AUTHOR]