Pliocene Dainenji Formation is distributed in the Pacific Ocean side of the Fukushima Prefecture. The depositional age is from 4.18 to 2.6 Ma. We carried out facies analysis and geochemical analysis, such as total organic carbon (TOC), total sulfur (TS), and stable carbon isotope ratio of organic matter (δ13Corg). Our results are as follows : (1) Abundant land-derived organic matter was transported to the shelf and was preserved in the sediment in warm period (3.75-3.5 Ma), (2) Productivity of marine organism increased in the early cooling period (3.5-3.35 Ma), (3) The considerable variations in TS, TOC and δ13Corg are seen in cooling stage after 3 Ma, which succeeded to the Quaternary ice age. Theses considerable variation are shown in δ18O curve of the same age.
