@article{oai:niigata-u.repo.nii.ac.jp:00028225, author = {青木, 滋 and 仲川, 隆夫}, journal = {新潟大学積雪地域災害研究センター研究年報, 新潟大学積雪地域災害研究センター研究年報}, month = {Mar}, note = {A study on the Late Quaternary deposits in the Niigata Plain was carried out by analyzing many records of drilling. As a result, the Late Quaternary deposits overlying the Buried terrace gravels in this area, can be subdivided into three formations; the Nishikanbara formation, Shirone formation and Kurotori formation in ascending order (Fig.3 and Table 5). The Buried terrace gravels comprise four members; Btg.I, Btg.II, Btg.III and Btg.IV in descending order. The Nishikanbara formation is composed mainly of alternation of sand and mud with thin layers of peat. The results of C^<14> dating show that the age is 25,000 to 26,000 YBP (Wh_1/ Wh_2). The Shirone formation is lithologically divisible into three units, namely lower, middle and upper members. The lithology of the lower unit of this Formation is smilar to the Nishikanbara formation, however, N-values of this unit are less than the underlying Nishikanbara formation. The middle unit consists mainly of silt and clay which considered to have deposited under marine or brackish environment (Fig.6). The upper unit consists of two major lithofacies. Along the coast of Japan Sea, the distribution of thick sand with high N-value which deposited in sand dune or bar can be recognized as shown in Fig.7. In inland area of those sand deposits, non-marine lagoon deposits of silt and clay are widely distributed. There is a remarkable unconformity between this formation and the underlying Nishikanbara formation. The Kurotori formation is composed mainly of loose sand, soft mud, peat and alternating of sand and mud, which extends widely in the Niigata Plain. At the base of this formation, the buried valley systems are well developed in the subsurface of Niigata City and these bottoms of the valleys attain to about 40m below sea level (Fig.7). The Kurotori formation is probably correlated to the Holocene Yurakucho formation in the Downtown of Tokyo (Table 7). From the viewpoint of subsurface stratigraphy and lithology of the Late Quaternary deposits, Niigata Plain can be subdivided into several types of ground geology as shown in Fig.9 and Table 8. This map is considered to be one of the basic map for various construction works in the surveyed area.}, pages = {25--40}, title = {新潟平野の地盤地質について}, volume = {2}, year = {1980} }