A study of the Coal Sedimentation in the Jôban Coal Field. (3)

Subsurface structure of the southern margin of the Jôban Coal Field

Abstract

Until 1951, environs of the Kawaziri station of the Jôban line were thought to be the southern margin of the coal field. In the present paper the writers have proved that the southern extension of the coal seams and the coal bearing formations is not only extended in the environs of Ogitsu station but may be spreaded even to Hitachi city, Ibaraki Prefecture.
The Shiramizu group in the mapping area is directly overlain by the Tags group with marked clino-unconformnity and its outcrop is observed at Iwamoto. Moreover, the well drilled lately by C. E. A. C near Ogitsu-hama also shows the full development of the Shiramizu group excepting the Shirasaka shale formation under the Taga group.