The Pleistocene Takano Formation, which is distributed in Takano, northern Nagano Prefecture, consists of lake sediments with many tephra layers. Pollen spectra from the Takano Formation are correlated to those from Lake Nojiri and Lake Suwa, using widespread tephra layers as key beds, to clarify the regional vegetation changes reflecting climatic oscillations.
Tephra layers from the Takano Formation are identified by the compositions of grain and heavy minerals; the refractive indices of volcanic glass, orthopyroxene, and hornblende; and the major element composition of the glass. As a result, tephras Tt-D, Aso-3, On-Pm1, K-Tz, On-Kt, Aso-4, On-Ng, Tt-E, DKP, and AT are recognized in ascending order.
Pollen analysis was done for the sediments from 2.2m below the Tt-D horizon to 2.0m above the DKP horizon, covering about 11.5m in stratigraphic thickness. Eight local pollen assemblage zones, from the bottom TKN-I to VIII, are established based on the changes of major pollen types. Zones TKN-I to VI show high occurrences of Cryptomeria and Cupressaceae-type pollen, which characterized the Early Glacial (MIS 5a-5d) pollen assemblages in central Japan. Zone TKN-I is characterized by abundant Pinaceae pollen with Cryptomeria pollen, which indicates a cool climate. TKN-II (intercalating Tt-D) is characterized by pollen of temperate deciduous broadleaved trees such as Quercus subgen. Lepidobalanus, Carpinus/Ostrya, Fagus crenata type, Ulmus/Zelkova/Hemipletea, and Cercidiphyllum, which show the warmest climate conditions in this section. TKN-III (intercalating On-Pm1, K-Tz) yields more Pinaceae pollen with less pollen of temperate deciduous broadleaved trees than TKN-II, and TKN-IV (intercalating Aso-4) is characterized by abundant Pinus subgen. Haploxylon and Betula pollen, reflecting a climate change to cold and dry. TKN-V (On-Ng is near the bottom) yields more values of deciduous tree pollen, which indicate a warm climate. TKN-VII (intercalating Tt-E and DKP) is characterized by dominant Pinaceae pollen (Picea, Abies, etc.), and Larix pollen, indicating remarkable cold and droughts in this zone. TKN-VIII is characterized by Picea and temperate broadleaved tree pollen, and was under a warm climate. These environmental changes are supported by the correlation to the pollen spectra of adjacent areas using widespread tephras as key beds. These correlations allow for a new chronological aspect of the horizon of DKP correlating to MIS4.

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vWe identified three fossil foraminiferal assemblages from the cored sediments (GS-KG-1) of the Middle to Upper Pleistocene Kioroshi Formation, Shimosa Group, at Kawaguchi, Saitama Prefecture, central Japan. The Kioroshi Formation in the study area is composed of lower muddy incised-valley fills and upper widely distributed, alternating beds of sand and mud. On the basis of the fossil foraminiferal assemblages, the formation is subdivided into three zones: Zones I and II in the lower part and Zone III in the upper part, in ascending order. Zone I is characterized by the Ammonia beccarii forma 1 assemblage, strongly indicating an inner bay environment. The Buccella frigida assemblage occurs in Zone II, and represents an inner to middle bay environment. The high abundance of B. frigida in Zone II suggests an influence of cold water. Zone III is characterized by the Miliolidae-Rosalina australis-Elphidium kusiroense assemblage, and seems to represent a middle to outer bay environment. The faunal succession in the cored sediments evidences development of a bay environment related to the late period of transgression from the Marine Isotope Stage 6 to Stage 5. In addition, our results show that the high abundance of B. frigida is a critical tool to distinguish the incised-valley fills of the Kioroshi Formation from the uppermost latest Pleistocene-Holocene incised-valley fills in Arakawa, Nakagawa, and Tokyo Lowlands.

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On the eastern margin of Toyama Plain, northern part of central Japan, late Quaternary fluvial terraces are well developed and divided into 9 levels: Terrace I to IX in descending order. The NNE- to NNW- trending Uozu fault extends 30km along the eastern margin of Toyama Plain and is associated with several branch faults. The ages of the terraces have rarely been reported in this area, due to the scarcity of outcrops and the lack of visible tephras. Therefore the author has carried out a drilling survey on the terraces to obtain loamy soil overlying the terrace deposits. The loamy soil consists of surface black soil and weathered brown, unsorted clay. The terrace deposits are composed of well-sorted silt and gravel beds of fluvial origin. The tephra horizon was recognized by wet sieving at 5-cm intervals and identification of volcanic glass and minerals under a microscope. The Kikai-Tozurahara Tephra (K-Tz: 95ka), characterized by a low index (n=1.497-1.499) of volcanic glass, is contained at the lowest part of loamy soil in Terrace III, and the Daisen-Kurayoshi Pumice (DKP: 55ka), characterized by colored minerals, is found at the lowest part of the loamy soil in Terrace IV. So Terrace III seems to have been formed in the Marine Isotope Stage (MIS) 5c or MIS 5c-5b boundary (95-105ka), and Terrace IV in MIS 4 or MIS 4-3 boundary (60-70ka). The DKP tephra is also found in the fluvial silt in Terrace V. Therefore, Terrace V is considered to have been deposited in MIS 3 (45-55ka). The Uozu fault deforms these fluvial terraces accumulatively. The vertical displacements of Terrace I to IX are as follows: 70-128m (Terrace I), 42m (Terrace II), 36m (Terrace III), 10-23m (Terrace IV), 31m (Terrace V), 3-4m (Terrace VI), and 1-2m (Terrace VIII). Based on the terrace ages and vertical displacements, the average vertical slip rate of the Uozu fault is calculated to be 0.2-0.9mm/yr.

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Three sedimentary cores recovered from the Iwanuma area in the southern part of Miyagino coastal plain, Miyagi Prefecture, are examined by means of diatom and pollen analyses to clarify the sedimentary environment and past vegetation. The Holocene deposits in this area are subdivided into the lower part composed mainly of silt, the middle part composed of sand, and the upper part composed of irregularly alternating beds of sand, silt, and peaty silt. From the diatom analysis, the sedimentary environment in this area is as follows. At about 10, 000yrs BP a tidal flat environment was created in response to the sea-level rise called the postglacial transgression, and the lower part of the silt bed was deposited. After that, an inner bay environment pervaded owing to the continuous sea-level rise, and consequently the middle sand bed was deposited. The terrestrial environment became established after the emergence of this area about 3, 500 ¹⁴C yrs BP. The pollen analysis indicates that the temperate deciduous broad-leaved forest dominated by Quercus, admixed with Fagus and Carpinus, has covered the surrounding hilly lands since about 10, 000 ¹⁴C yrs BP. In the fairly stable vegetation during the Holocene mentioned above, Ulmus-Zelkova and Cryptomeria have existed in small amounts since the early Holocene, and increased after about 8, 000 ¹⁴C yrs BP because of local topographic changes.

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