MESOZOIC RADIOLARIANS FROM RHYTHMICALLY LAYERED SEDIMENTS OF THE RIMSKY-KORSAKOV ISLANDS (PETER THE GREAT BAY, JAPAN SEA) AND THEIR SIGNIFICANCE FOR DETERMINING THE TRIASSIC-JURASSIC BOUNDARY

Abstract

The results of the biostratigraphic study based on the radiolarian analysis of the rhythmically layered terrigenous deposits from the Islands of the Rimsky-Korsakov Archipelago (Peter the Great Bay, Japan Sea) have been presented. These deposits are most similar to the medium-grained turbidites. For the first time the distribution and stratigraphic division of the boundary sediments of the upper Triassic and lower Jurassic separated by a marking layer were substantiated in the research area. On the basis of comparisons with isochronous zonal units of the Pacific and Tethyan areas in the upper Triassic sediments of the studied sections, layers with Globolaxtorum tozeri (upper Rhaetian) were established, and in the lower Jurassic zone Pantanellium tanuense Zone (Hettangian) was traced and layers with Parahsuum simplum (Sinemurian – Pliensbachian) were established.