Geological Investigation of the Niigata Oilfield

General stratigraphy and palaeontology on the Niigata Oilfield region are described and discussed on the compiled basis of the recent geological and geophysical survey with the application of the knowledge of oceanography, palaeoecology and sedimentlogy.The writer proposes the new stage scheme for this region, they are, from lower to upper, the Tsukawan, the Teradomarian, the Shiiyan, the Nishiyaman, the Haizumean, the Yamayan, the Ogunian and Oyaman. Fig. 1. shows the columuar section of the Tsukawan. Fig. 2. is the isopach map of the shiiya formation. Here, the writer gives a new idea on the developmet of the geologic structure of this region. That is, although there are some differences in degree on scale, on age and in place, the deposition, local denudation, folding and faultng are carried on continuouously and progressively, accompanied with the upheaval and subsidence of the basement bl_??_ck and igneons action. Also at present, it is carrying on. This idea is shown diagramatically in Fig. 3, in which direction of arrow shows one component of the four-dimensioned vector including time factor. This phenomenon, the word of "evolutional cnange" being proposed for it, is believed to be the true attitude of the earth's crust.