Jurassic radiolarians and age of cherty rocks in the Povorotnyi Cape,the Taigonos Peninsula (northeast Russia)

Radiolaria-based dating of chert intercalations in basaltic sequences of ophiolitic associations, which are widespread in the west of circum-Pacific foldbelt being barren of macrofossils, is an important source of information about tectonic events and factors responsible for opening and destruction of basins floored by oceanic crust and for emplacement of relevant tectonic sheets into accretionary prisms and orogenic structures. Described in the work are the Middle (Bajocian-Callovian), Middle-Late (Callovian-Oxfordian) and Late Jurassic (Kimmeridgian-Tithonian) radiolarian assemblages. According to taxonomic composition and morphology of radiolarian tests, the first assemblage is of the North Tethyan type, while the other two are of the Boreal affinity.