Variation of the external shell sculpture in three species of Late Cretaceous inoceramid bivalve Sphenoceramus [S. naumanni (YOKOYAMA), S. orientalis (SOKOLOW) and S. schmidti (MICHAEL)] from the Upper Yezo Group in northern Hokkaido were studied ontogenetically. Three growth stages β, γ, and δ, characterized by the pattern of commarginal costae, were recognized in S. naumanni and S. schmidti, while the γ-stage is absent in S. orientalis. The size of the growth stage boundaries, the onset size of the divergent ribs or commarginal undulations of the shell, and the rib density in each growth stage were analyzed in a total of 252 specimens belonging to the three species. S. orientalis is distinguished by the early appearance of commarginal undulations of the shell in the β-stage. Large size and lack of divergent ribs in the β-stage is characteristic of S. naumanni. Low rib density in the δ-stage, occasionally found in S. schmidti, helps to identify younger individuals lacking the divergent ribs.

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Volcanic rocks were found at Eurasian side slope of Suruga Trough convergent plate boundary by dive 708 of the “Shinkai 2000”. These volcanic rocks crop out at the eastern lower slope of the Senoumi North Bank at a water depth of 1,500 m. Two types of phyric andesite rocks, hypersthene-augite-andesite and hornblende-augite-andesite, were noticed, both containing distinctly large phenocrysts.
These volcanic rocks overlie the conglomerate layers that date from 0.91 to 0.82 Ma within nanno fossil biostratigraphic horizon CN 14a, so the age of igneous activity may be a little yonger than the nanno fossil age. The volcanic rocks have strong similarities with regard to the rock types, geological situation, and stratigraphic relations to the rocks of the “Iwabuchi pyroclastic rocks and Iwabuchi volcanoes group”. These rocks cover Kambara Conglomerates at Kambara Hills 45 km to the north of this site.
Nanno fossil age obtained from a muddy layer intercalated in “Iwabuchi pyroclastic rocks” is 0.92–0.46 Ma, and the “Iwabuchi pyroclastic rocks” indicate paleomagnetic reversed polarity. So the volcanoes in the Suruga Trough area would be active in the later part of the Matuyama reversed magnetic polarity chronozone and also be younger than the Jaramillo sub chronozone of 0.92 Ma.
The rock samples of hornblende-augite-andesite are conspicuously reddish-purple due to hematite micro crystals scattered through the groundmass and also replacing the phenocrysts, and hornblende phenocrysts are severely opacitized oxyhornblende. These facts suggest that the volcanic activity happened under an oxidizing environment, so the eruption might be aerial or in very shallow sea. The tectonic situation and geological environment would be very different from the persent, and more than one thousand and several hundred meters depression has occurred since then.
Further research about convergent boundary volcanic activity is necessary not only for local geological interest but also for solving fundamentally important problems of tectonic history of the whole Suruga-Nankai Trough region and tectono-magmatic phenomena.

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Stable isotopes of oxygen and carbon are useful tools in understanding the paleoclimates. The stereome isotopic data of an organism is indicative of the isotopic composition of the ocean water where the organism lived. In this study we measured stable carbon and oxygen isotopes of the shell an Antarctic Bivalvia Laternula elliptica. Samples of fossil Antarctic Bivalvia L. elliptica shell from the Pliestocene (46 ka) and Holocene (3.5 ka–4 ka) were collected from Lutzow Holm Bay and from the Recent L. elliptica at MucMurdo Sound in Antarctica. The quantity of meltwater from ice sheet militating the ocean water can be estimated from the δ¹⁸O of shells of Laternula. Detailed microsampling within a shell also sheds light on seasonal isotopic variation.
We measured two modern as well as three fossil shells (3.5 ka–4 ka) and some 46 ka shell fragments. The δ¹³C values suggest that in L. elliptica inception of carbon occurred during the course of growth. The δ¹⁸O values have a seasonal variation of about 1‰. The light values are suggestive of addition of meltwater indicating summer season and the heavy values are likely to winter. This seasonality gives important information about the life span of a molluscan shell. Using these data the life span of the Recent L. elliptica might have been for 7 years and that of the fossil Laternula about 9 years. The δ¹⁸O fluctuation within Recent shells are in the range of 1‰, and that of the fossil shells in 3‰, which shows that there was a greater variation of oxygen isotopes during the course of life 3.5 ka–4 ka than the Recent. The ¹⁸O depleted value suggests that there was mass mixing of meltwater with the sea water at 3.5 ka–4 ka which decreased toward the Recent. In this study the shell data of the three periods indicate that the biggest meltwater effect was the highest recorded at 3.5 ka–4 ka and the second was around 46 ka.

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The occurrence, mineralogy and stable isotopic characteristics of axinite and datolite-bearing veins in the Mt. Nio area of the Setogawa Belt in Shizuoka were described. Along three valleys of Abe River (Kuchisenmata, Setozawa and Okunosawa), cobbles and outcrops of axinite bearing veins are found along fractures in greenrocks. Four outcrops of green-rocks at the valley head of Okunosawa, axinite bearing veins about 20 cm in width and 1 m in length were observed. Epidote, pargasite, calcite and quartz were observed in the axinite and datolite bearing veins. Carbon and oxygen isotopic values of calcites coexisting with axinite and datolite showed a nearly constant value for oxygen and were highly variable for carbon. This implied that the temperature of the hydrothermal water which formed these mineral veins was constant and the source of carbon in the hydrothermal fluid probably mixed with magmatic carbon and organic derived carbon accompanying the accretional processes of the Setogawa Belt.

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A technique for analyzing trace amounts of Ba. Be, Li, Pb, Rb, Sr, K and Ti in rock samples is described. In this technique, rock or mineral samples are decomposed by HF-H₂SO₄ or HF-HNO₃ and the trace element concentrations are determined by graphite furnace-atomic absorption spectrometry (GF-AAS) using standard addition. The detection limits for this method are < 6 pg for Ba, Be, Li, Pb, Rb and Sr and < 40 pg for K and Ti. The trace element concentrations determined for eight GSJ rock reference samples showed good agreement with the recommended values, and the analytical errors were less than 5%. This technique enables to obtain reliable trace element compositions of rock and mineral samples even if the sample sizes are very small (< 10 mg).

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Recently the experimental result which insist nutrient up-take depends on flow rate by ATKINSON (1987) and ANDREW (1998) has been reported. The aim of this study is re-determine of gross phosphorous and nitrogen up-take which determined by MIZUOKAMI (1995 MS) and KUROSAWA (1996 MS).
The statistical examination between calculation and observation for nitrate correlation coefficient was γ² = 0.88 and for nitrate was γ² = 0.76. But for phosphate and nitrite correlation coefficient was very low, suggesting being another fluxes. Gross uptake rate of nutrient in 1994 was 1.4 times higher than in 1993. Because flow rate in 1994 was 3.4 times higher than in 1993, although TIN concentration in 1994 was same as that 1993.
Assuming a zooxanthellae’s C/N ratio of 20, gross organic carbon production rate calculating with this model was smaller than that calculated change of DO concentration in 1993, but it was same order of magnitude as DO in 1994.

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Sub-micrometre particles (SMP) are one of the important forms of organic matter pools in sea water, because these particles are present in sea water as transit states between dissolved and large particles of organic matter. It is considered that large particles play an important role in the carbon cycle incorporated to the biological pump, but little is known about SMP. Recently, it has been reported that SMP are present very abundant in sea water. In this study, the vertical and temporal distributions of SMP with the size range from 0.6 to 200 µm from warm core ring (the western North Pacific ocean) were measured using a Coulter Counter Multisizer II. The total volume of SMP showed maximum value of 9.9 × 10⁶ µm³/ml. These results are compared with planktonic and non-living compositions. The total volume of SMP in-creased during night as non-living particles. The results suggest that SMP is correlated with biological processes, especially microbial food-web, but the whole vertical distribution of SMP might be determined primarily by physical structures that is the depth of the pycnocline in the ocean.

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Nutrient distributions (NO₃⁻, NO₂⁻, PO₄³⁻, SiO₂) were measured in Kuroshio Warm-Core Ring (WCR) during the Hakuho-maru cruise KH-97-3.
WCR is occurring as a transit zone between the Kuroshio and Oyashio. In generally, it is thought that organic production is much greater at the edge of WCR than at the center of that. Concentration of chlorophyll-a is also higher at the edge of WCR than center of that. But, We have no clear interpretation about the mechanism of nutrient supply, especially to the edge of WCR. We had studied hydrographic of WCR structure using potential T, S, σ_θ and nutrient.
Consequently, I had gotten new hypothesis on WCR structure: The edge of WCR has lower than sea surface and mulchlayered structure from surface to bottom of WCR. This WCR structure will bring to the small scales upwelling around top of edge, which supplies nutrient to the edge of WCR, and maintains the higher organic production at the edge.

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