1983 Volume 33 Issue 180 Pages 253-257
Calcareous nannofossils were identified from some drilling cores of the southern Shakanai mining area. The result is as follows.
1. The M3 mudstone is correlated to CN4 of Coccolith biostratigraphic zone by BUKRY, and the lower part of M2 mudstone to CN5a and CN5b. But, nannofossils were not found from the M1 mudstone and the upper part of M2 mudstone.
2. Stratigraphic horizon of kuroko deposits can reasonably be correlated to CN5a (13.9 Ma-12.3 Ma), and may possibly extend to a part of CN5b and CN4.
3. Globorotalia-Hopkinsina-Prunopyle Zonule, which is foraminiferal and a radiolarian fossil zone, established in the Shakanai mining area, is thus subdivided into CN4, CN5a and CN5b.
