The analysis of the composition and relative stratigraphic occurrences of radiolarian assemblages in the Neogene formations of the Niigata sedimentary basin has been carried out by the writers, after a total about 4500 samples collected from main sections and 12 wells was under examination.
In this area there are seven characteristic radiolarian assemblages, namely Lp, Ta-Ar, CtLt, Ln, Tj, Tj-Ar and Form B types. While, the radiolarian zones, namely, Cyrtocapsella tetrapera, Lychnocanium nipponicum and Thecosphaera japonica zones were proposed by the writers.
In this paper, some problems concerning the stratigraphic and geographic occurrences of these radiolarian assemblages, and the relation between radiolarian and planktonic foraminiferal zones were discussed. These results are shown in figure 14.
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