微化石研究の現状と石油地質学への応用

―古海洋環境変化とは何か―

抄録

Micropaleontology has been used for both the determination of geological age and correlation to the Neogene-Quaternary formations in the oil fields in Japan. However, as it is against the rule of International stratigraphic guide to correlate to standard formations based on micropaleontology, it sometimes causes confusion of the stratigraphy of the oil fields.
Micropaleontology is a useful tool for not only the correlation to the geological age but also the paleoenvironment analysis. The ecology of calcareous nannoplankton is also applicable to reconstruct the stability of the surface ocean condition related to nutrient supply during the Miocene to Pleistocene. I describe in detail the characteristics of the microfossils both for the determination of geological age and for paleoenvironmental analysis, and introduce the utility of micropaleontology for petroleum exploration in this papaer.