Abstract
The purpose of this study is to produce quantitative data on the clastic sediments belonging to the upper formations of the Neogene, the Shinjo group, developed in the Shinjo oil-field. The units selected for analysis are the lignite-bearing formations, demarcated by the characteristic sandstone facies, exposed along the Oguni river near Nagasawa in the eastern margin of the basin.
Four types are recognized as the result of the mechanical analysis (median diameter, coefficient of sorting, standard deviation, skewness, and kurtosis) and these types, A, B, C and D, are practically correlated with the Mitsumori, Sakegawa-Yamuke, Shimizu, and Izumikawa formations respectively. It is worthy to note that among these four types a clear line is drawn between the former two types, A and B, and the latter two types, C and D, and also it clearly corresponds the marker bed (K4) at the basal part of the Shimizu formation traceable along the major parts of the marginal part of the Shinjo basin.
