南関東地方の新第三系および第四系の微化石層位学的研究

• Main Author: 菊池 良樹
• Format: Report
• Language: Japanese
• Published: 東北大學 1964
• Subjects: Planktonic foraminifera
• Online Access: http://hdl.handle.net/10097/33153; https://tohoku.repo.nii.ac.jp/?action=repository_uri&item_id=13026; https://tohoku.repo.nii.ac.jp/?action=repository_action_common_download&item_id=13026&item_no=1&attribute_id=18&file_no=1

In 1955, Professor Kiyoshi Asano of the Tohoku University for the purpose to establish the stratigraphic sequence of the Neogene Foraminifera of Japan, organized a research group and the central and eastern parts of the Boso Peninsula, Chiba Prefecture, were selected as the standard area for the project. The writer, a member of the research group, has been engaged in the work on the Neogene and Quaternary biostratigraphy in the Southern Kanto region by the smaller Foraminifera. In 1957, the writer was appointed the position of micropaleontologist of the Teikoku Oil Company where he has continued his study. Especially he has endeavored to work out the Miocene, Pliocene and Pleistocene biostratigraphy by the smaller Foraminifera obtained from the drilled well-cores distributed in the southern part of the Kanto region. The Cenozoic formations of the Miura Peninsula, Kanagawa Prefecture are classified, as shown in Table 1 and divided into two zonules by the benthonic Foraminifera collected therefrom. As to the subsurface geology in the Hodogaya area, the formations shown in Figure 2 were distinguished from the micropaleontological data of the drilled wells and correlated with the standard stratigraphic sequence of the Miura Peninsula. Concerning the Miocene formations no difference was recognized in the foraminiferal associations between the Miocene surface samples of the Miura Peninsula and of the subsurface materials from the Hodogaya area. However, in the Kazusa Group which ranges from Pliocene to Pleistocene, the foraminiferal assemblages indicating a shallow water habitat are found in the southern part of the Peninsula whereas the deep water assemblages in its northern part. Abundant planktonic Foraminifera were recognized in the samples from the base of Nojima formation in the Miura Peninsula. The same species of planktonic Foraminifera were found in abundance from the cores of depths shallower than 760 meters in the Hodogaya well R-1. This paleontological evidence shows that the subsurface formation in the ...