Paleozoic stratigraphy of the Shahmirzad area in the east Elburz Mountains, north Iran is described. The Carboniferous Mobarak Formation consisting of banded limestone and shale is divided into ten lithological units and correlated with the Tournaisian and Lower Visean. A tabulate coral Vaughania sp. occurs from the lowest unit (Unit A) of the formation, which is correlated with the lowermost Carboniferous biozone. Geological ages of Kueichouphyllum and Keyserlingophyllum that were formerly described as the Upper Visean rugose corals in this area or north Iran are revised to the Upper Tournaisian.

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Chemical comparison between essential clasts and matrix of the Late Cretaceous Setogawa Ash-Flow Sheet (AFS) of the Nohi Rhyolite suggests the significance of whole-rock chemical analysis for ignimbrites. The Setogawa AFS, which filled the cauldron, was welded and devitrified, and altered under hydrothermal conditions after caldera collapse, as is often the case with the other ancient intracaldera ignimbrites. But the essential clasts and matrix of the Setogawa AFS maintain vertical chemical zoning patterns correspond to the modal composition, and show similar chemical trends to co-genetic granitic rocks. The evidence indicates chemical alteration was very weak and no chemical exchange on the whole sheet scale occurred. The effects of contamination are negligible because the matrix of the Setogawa AFS shows no chemical shift to the lithic fragments, as suggested from minor contents of lithic grains. The matrix is less abundant in vitric material, which was devitrified to be aggregates of minute quartz and feldspar crystals, than the essential clasts due to selective loss of vitric ash during the ash-flow eruption. The selective sorting caused the matrix to have a little more mafic composition than the original matrix. But the present matrix shows very little chemical shift from the essential clasts. Because the magma of the Setogawa AFS mainly consisted of liquid components which formed vitric materials, the selective loss of vitric ash did not seriously change the chemical composition of the original matrix. The matrix shows narrower chemical variation than the essential clasts, the fact of which indicates components of the matrix were well mixed during the ash-flow eruption. Considering these characteristics of the matrix, the whole-rock chemical analysis for ignimbrites is available to examine the average composition of erupted magma because ignimbrites are chiefly composed of the matrix.

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The Paleogene Otonashigawa Group in the Shimanto Belt in the Kii Peninsula is composed mainly of mudstone, flysch-type alternation of sandstone and mudstone, sandstone and conglomerate. It reaches 1700m in thickness, comprising an upward thickening- and coarsening-sequence as a whole. The Otonashigawa Group is composed of two formations in the reported area, that is, the Uridani and Haroku formations in ascending order. The Uridani formation is composed of hemi-pelagic and pelagic mudstones associated with reddish and greenish mudstones in the upper part. This formation is outer trench fill deposit. The Haroku formation consists of flysch-type alternation of sandstone and mudstone, sandstone and conglomerate. The Haroku formation is deep submarine fan deposits. The Otonashigawa Group is an accretionary prism, which has the E-W trending zonal structure parallel to the southwestern Japan arc. It is characterized by fold and thrust structures dipping north, by which the Uridani and Haroku formations are repeated several times. These folds and thrusts were later bent by conjugate folds, which were trending NE-SW and NW-SE. The bend structures were mainly formed before the sedimentation of the lower middle Miocene Kumano and Tanabe Groups. The maximum principal stress axis (σ1) deduced from the conjugate folds is E-W in horizontal plane. The surveyed Kizekkyo area is a fold and thrust structure developed between Hongu-Minachi fault and Furuyadani fault in the Otonashigawa Belt. The bend structure of Furuyadani fault was precisely described in this paper. The Otonashigawa Group was deformed by two different successive stress fields, one of which was a N-S compressive stress field during sedimentation and accretion at the subduction zone, and the other a later E-W compressive stress field, which formed conjugate folds and bend structure. This younger stress was supposed to be caused by the movement of the Pacific Plate.

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Stream sediments from the Hino River in Tottori prefecture, SW Japan, carry the imprints of detritus from two geographically separated geologic units with high geochemical contrast. Major and trace element X-ray fluorescence analyses were made of two size fractions (<180 and 180-2000μm) from 101 samples collected from the main channel and tributary streams within the catchment. Although most of the drainage basin consists of felsic granitoid and volcanic rocks, small areas of basic and ultrabasic rocks occur in the headwaters, and adakitic Mount Daisen rocks crop out extensively in the lower reaches. In the upper reaches, inputs of basic-ultrabasic detritus cause enrichment in Cr, Ni, V, TiO2, Fe2O3, and MgO. Abundances of these elements decrease progressively downstream, due to dilution by felsic detritus derived from the granitoids. This effect is well illustrated by Cr/V ratios, which decrease steadily after the first input of basic-ultrabasic detritus. Granitoid inputs are marked by increased abundances of incompatible elements, especially Th, Ce, Y, and Zr. Contribution from Mt Daisen in the lower reaches is marked by increase in Sr, CaO, Na2O and decrease in Y, leading to distinctive Sr/Y-Y signatures in the sediments. The effects of weathering and sorting on the composition of the sediments also vary according to the source rock. Sediments derived from granitoid-volcanic felsic rocks show greater fractionation between the size fractions than those originating from Daisen, and also show more intensive weathering effects, although source weathering is only moderate overall. The geochemical compositions of the Hino River sediments thus clearly reflect the controls exerted by source lithotype, dilution effects from contrasting sources, sorting, and weathering.

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The formation of melanic horizons so called "Kurobokudo" was chronologically studied in the tephra-soil sequence of the Ashitaka Loam at the foot area of Ashitaka Volcano, central Japan to discuss the history of Kurobokudo formation by examining soil chemical properties and paleo-phytolith assemblages. The black humic soils intermitted between tephra layers were recognized continuously from the lowermost layer of Upper Loam to the surface soil. The pH(NaF) value exceeded 9.5 through the tephra-soil sequence from the uppermost part of middle Loam. Based on the criteria of andic property which is given by pH(NaF)≧9.5, the analytical results implied that the increasing humus accumulation was recognized not only in Upper Loam but also in the uppermost part of Middle Loam. Paleo-phytolith assemblages were dominated by phytoliths of dwarf bamboo such as Pleioblastus and Sasa, and phytoliths of Panicoideae. This indicated that the warm-cool condition, under which Melanic horizons could be sufficiently formed, had continued since the age of the uppermost part of Middle Loam. Melanic Index (MI) values in Upper Loam were generally under 1.7, which implied the existence of the A type humic acid. While Middle Loam was determined as non-A type humic acid due to its MI value exceeding 1.7. These facts suggested that vegetation had transformed from forest to grassland around the age between Upper Loam and Middle Loam and then grassland dominantly succeeded. Since this vegetation change occurred almost simultaneously with the start of human activity in this area, supported by the archeological findings in the lowermost layer of Upper Loam and many archeological sites discovered throughout Upper Loam to Holocene soils, it was inferred that human activity had affected to generate melanic horizons associated with changing the vegetation from forest into grassland. The Yasumiba bed, the uppermost layer of the Upper Loam including a famous archeological site (Yasumiba-iseki), and Kuri-iro bed are the two definite non-melanic horizons formed in the tephra-soil sequence above the base of Upper Loam. It was estimated that the Yasumiba bed was formed without melanic facieses during vegetation decline in Glacial age, which might had been induced by the excessive movement of people from the higher elevated area towards the foot area of Ahitaka volcano under milder climate conditions. On the other hand, the Kuri-iro bed, a Holocene soil developed above the definite melanic bed named as "Fuji-kuro", could be recognized as a forest soil classified as Yellow Brown Forest soils due to its rich phytolith assemblages derived from evergreen broad-leaved trees. It was concluded that the following two boundaries existed in the history of melanic horizon since the last Glacial age 1) The later boundary at the age of ca.10ka corresponding to global warm period between Pleistocene and Holocene, and 2) the earlier boundary at the age of ca.32ka corresponding to the beginning of human activity in Japan Islands.

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