The Esashi dunes developed on Ohma Marine Terrace (50-65m high a. s. l.), north of Esashi, Oshima Peninsula, contain 5 buried humic soils within the 20-30m-high profile. Grain size distribution, humus properties, spectrum color, pH value in NaF, and mineral composition were examined for 40 samples taken from the dune profiles to discuss the genesis of these dunes and the Jin-ya Loam layer underlying the dunes. The results are summarized as follows:
(1) The grain size distribution of the dune material was characterized by distinct peaks in two fractions: sand (20μm≤) and silt-clay (20μm>). The weight percentage of the silt-clay fraction was about 60%, 20-35%, and 15-20% at the bottom, middle, and top of the dune profile, respectively. The constitution of grain size shifted to finer fractions in deeper layers, and Jin-ya Loam mainly consisted of silt-clay fraction.
(2) The carbon content of the dune materials ranged from 1 to 7 wt%; the type of humic acid was defined as A-type, using the values of MI, PI, and ΔlogK. In contrast, the humic acid of Jin-ya Loam was assigned as P-type.
(3) Degree of spectrum color (a^*, b^*, L^*-value), measured for organic carbon free samples, showed that dune samples had the same yellowish hue (10YR) as the Jin-ya Loam, the brown loam.
(4) pH (NaF) value of samples from both the dune and the Jin-ya Loam layer was≥9.5, which indicated the properties for tephric materials.
(5) Mineral composition(63-125μm)of Jin-ya Loam was inferred to be partly originated from volcanic matreials including tephra fall deposit (ex. Nigorigawa-a tephra, ca 12ka).
From the above facts, it was suggested that the Esashi dunes have developed in a different process from coastal dunes. Silt-clay fractions in the dune were inferred to be materials from Jin-ya Loam, mainly composed of tephras which were eroded and reworked in the dunes. Accumulation of humus was considered to be associated with the deposition of the fine fractions, which characterized the humus properties of the Esashi dunes to become similar to that of Kuroboku-soil. Such kinds of dunes, in which silt-clay fractions originated from tephra are the important components as well as sand fractions, can be proposed as tephricloess dunes.

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Pollen analyses of surface sediment samples collected from coastal mangrove swamps in Dongzhai and Qinglan, northern Hainan Island, China, are carried out to study the relationship between surface pollen and mangrove vegetation. Six transects (1-6) from the Dongzhai and Qinglan mangrove swamps were used to examine local plant zonation pattern along intertidal zones. Four transects (1, 2, 5, 6) were sampled for pollen analysis to examine the relationship between the sedimentary environments and the zonation of mangrove swamps in the intertidal zones. All the palynomorph types extracted from surface sediment samples were counted, including pollen, fern spores, fungal spores and unknown or indeterminate remains.
The relationship among surface pollen, mangroves and local vegetation shows close linkages. Mangrove pollen taxa were roughly arranged by vegetation zones along the intertidal flat. Rhizophora pollen is markedly abundant, while Avicennia, Ceriops and Bruguiera are moderately abundant. The surface samples contained fewer pollen grains of other common mangrove types such as Excoecaria, Kandelia, Aegiceras and Xylocarpus. Exotic (non-local) palynomorphs were also present in most samples, however the most dominant types originated from the mangrove communities. We note that in northern Hainan Island mangrove pollen shows consistent distribution with their parent plant zonation, unlike common tropical terrestrial palynofloras without strong links with their parent vegetation largely due to low their pollen production, poor preservation, or unfavorable pollination mechanisms.

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Major element chemistry of glass shards collected from representative tephra layers (B-Og, Aso-1, Km4, Oga and AT tephra layers and Ikezuki tuff) as glass standard reference materials was determined by X-ray fluorescence spectrometry (XRF) and energy dispersive X-ray spectrometry (EDS). The mean compositions of the standard glass by XRF analysis have SiO₂ contents in the range of 65-78wt.%, recalculated on a volatile-free basis. The reproducibility of the EDS analysis was treated by a coefficient of variation plotted against the EDS analytical content on each element. The accuracy of the EDS results, plotted against XRF results for each element, have been evaluated in comparison with the XRF results as a standard. Least-squares fitting was applied to the data points. Furthermore, the raw analytical results by the EDS were corrected by using a coefficient of the linear function. The corrected EDS result obtained is consistent with the chemistry of identical tephra glass shards found by previous workers. The corrected EDS results agree with those obtained using the same procedure at an other institute, in spite of the different apparatus and configuration of the EDS system. Consequently our proposed procedure of the EDS analysis and correction is widely available for identification and correlation of tephra layers.

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Upper Pliocene to lower Pleistocene deposits extensively crop out around the neck of Motobu Peninsula, Okinawa-jima, Ryukyu Islands, southwestern Japan. We propose a major revision of the previous stratigraphic scheme for the upper Pliocene to lower Pleistocene deposits and provide a formal stratigraphic description. These deposits are divided into the Guga and Nakoshi Formations, in ascending order. The Guga Formation rests unconformably on the pre-Tertiary rocks and consists mainly of conglomerate. The Nakoshi Formation conformably overlies the Guga Formation and is composed chiefly of calcareous siltstone/sandstone. These deposits pass laterally into reef-complex limestone (the Ryukyu Group) which is distributed on the northern to western part of Motobu Peninsula. Calcareous nannofossil biostratigraphy indicates that the upper parts of the Guga Formation were deposited in early Pleistocene time, and that the lowest part of the limestone and the Nakoshi Formation are coeval, ranging in ages from 1.45-1.65Ma. This is the oldest known age of the Ryukyu Group. Coral reefs formed and the coeval siliciclastic and calcareous sediments accumulated on Motobu Peninsula in early Pleistocene time. In contrast, sedimentation prevailed by calcareous muds/sands and sandy carbonates in middle to southern Okinawa-jima, which is presumed to have been shelf edge to shelf slope at that time.

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Eniwa-a tephra (En-a), which erupted from Eniwa volcano, western Hokkaido, at 17ka BP, is composed of more than three fall-units in the southern part of the Ishikari Lowlands. The refractive indices of En-a volcanic glass are significantly different among fall-units. The refractive index is relatively high (n=1.510-1.514) in the upper fall-unit and low (n=1.505-1.510) in the middle and lower fall-units. It is generally accepted that the petrographic properties of some tephras differ considerably between fall-units. However, this has not always been considered in collecting samples and measuring petrographic properties of marker tephras. In order to obtain petrographic properties for tephra identification, we should take samples from every fall-or flow-unit at an outcrop near a source vent. The refractive indices of En-a volcanic glass from the Hidaka Range tend to have remarkably low values and large variances due to incomplete hydration in volcanic glasses.

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