Quaternary stratigraphy

Abstract

Generally, the Lower Pleistocene deposits are distributed in and around hilly districts in the Japanese islands, which lie conformably on the Pliocene sequences. They are represented by marine sequences of the Kazusa Group, the Kitaura Formation and the Soga Group; fluvio-lacustrine ones of the Osaka Group, the Uonuma Group and the Nanaorezaka Formation; volcanic sequence of the Yachio Group. Although the Middle Pleistocene deposits mainly cover the Lower Pleistocene sequences conformably, some of them in inland areas form fresh sequences in newborn basins. As representatives of them, the Shimonopporo Formation, the Ogasa Group and the Minami-Saku Group are examined stratigraphically. The Upper Pleistocene are composed of a variety of sediments such as marine, river terrace, lacustrine, volcanics, aeolian etc. Among them, the Shimosueyoshi Formation is taken as a typical sequence for marine terrace of the Last Interglacial, while the Nojiriko Formation in northern Central Japan is referred to a representative lacustrine sequence of the Last Glacial. Most of the Holocene deposits form the upper part of alluvial plains, valley plains and costal dunes. -from Author