The atmosphere-ocean system is often controlled by non-steady, sporadic and localized events. The events are, for example, the particulate removal of chemical substances from the ocean, the transport of continental aerosols, Kosa, to the ocean, the production and transport of sea salt particles, the gas exchange at the air-sea interface, the biological production in the ocean and its effect on the geochemical cycling and the formation of solid phases of Mn and U in the marine environment. The atmosphere-ocean system is so complicated that these events can not be easily explained by the laboratory experiments and we are often apt to regard that they contradict with the chemistry. One example of them is the removal mechanism of thermodynamically insoluble metals in seawater, which concerns the terms, "dissolved", "adsorption and desorption" and "equilibrium" in the natural system.

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Geochemical criteria for the discrimination of origins and depositional environments of siliceous sedimentary rocks are reviewed. Biogenic siliceus rocks containing radilarians and sponge spicules are extremely enriched in SiO₂ and show an inverse correlation between SiO₂ and hydrolyzates such as TiO₂, Al₂O₃, and Zr. This suggests that biogenic siliceous rocks are regarded as a mixture of clays and biogenic silica. Volcanogenic siliceous rocks, derived from acidic volcanoclastics, are characterized by low Fe₂O₃/SiO₂ and high Al₂O₃/TiO₂ ratios that change during magma processes. Hydrothermal siliceous-rocks are characterized by high concentrations of Fe, Mn, and low ratio of Al/(Al + Fe + Mn). Diagrams of SiO₂/TiO₂-Al₂O₃/TiO₂ and Al-Fe-Mn are useful tools for distinguishing origins of siliceous rocks. Hydrogeneous elements such as MnO and Co can be an important key to depositional marine environments. The intensity of hydrothermal activity calculated by fraction analysis may also be a criterion for depositional environment of siliceous sedimentary rocks with hydrothermal emanations. The results show that the bedded cherts in the Mino terrane, central Japan, had deposited in hemipelagic region and those in the Franciscan terrane, California, had deposited on or near some active ocean ridge.

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Magmatic hydrothermal solution is formed as a consequence of crystallization of magmas at shallow crust. The ascending magmatic hydrothermal fluid through the crust inevitably experiences large pressure and temperature changes. Pressure-temperature condition of the magmatic hydrothermal system overlaps with the subcritical region of NaCl-H₂O system, and the phase separation is regarded as a common and important differentiation process of the fluids. Since compressibility and thermal expansibility of hydrothermal fluids are large at high temperature and low pressure condition, large pressure and temperature dependence of equilibrium constants is expected in the P-T regions of the system. Large variations in the appearance of magmatic hydrothermal system are concluded to be due to the phase separation and the reactions with large pressure and temperature dependence under the large pressure and temprature gradients.

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Chemical and isotopical analyses were carried out of cored sample taken from Yatomi area, Aichi Prefecture, southwestern part of the Nobi Plain, in order to restore the paleoenvironment of this area. Based on analyses of nitrogen/carbon ratio and carbon isotopic ratio of sedimentary organic matter, acid-insoluble-sulfide content and its sulfur isotopic ratio in sediment, followings are clarified. (1) The Nobi Formation (12000〜10000y.B.P.) was deposited first under lacustrine/back-swamp condition, and later this swamp area was filled up with fluvial deposits. (2) The lowermost part of the Nan-yo Formation (10000〜8000y.B.P.) was deposited first under meromictic-lake condition. Sea-level rising began gradually and depositional condition became near shore condition about 9000y.B.P. But temporal stagnancy or lowering of sea-level occurred about 9000y.B.P. (3) The lower and middle part of the Nan-yo Formation (8000〜2500y.B.P.) was deposited under inner bay (off shore) condition. About 8000y.B.P., sea-level began to rise rapidly and depositional conditon changed quickly from near shore condition to off shore condition. About 6000y.B.P., depositional condition became most off shore condition, 30〜40km offshore. From about 5000y.B.P., the influence of land-derived deposits increased gradually. (4) The upper and uppermost part of the Nan-yo Formation (2500y.B.P.) was deposited under near shore to deltaic/estuarine condtion. The geochemical restoration of paleoenvironment is consistent with several paleontological restorations. The geochemical restoration method is useful for providing continuous information even for non-fossil layers.

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Na, K, Mg, Ca, Cl, Br, SO₄, HCO₃ and H₂SiO₃ in Masutomi spring and other Northern Yamanashi spring waters were determined. Masutomi spring showed very high salinity. On the basis of the deviation from the sea water defined in concentration (ppm) as δ_X= (C_X/C_Cl-C_X,sea/C_Cl,sea)×100(%), δ_T= Σ|δ_X| where X=Na, K, Mg, Ca and SO₄, Masutomi spring water seems to be very similar to sea water in the compositions : the equivalent quantities of the depleted compositions (Mg, etc.) are well balanced by those of enriched ones (Ca, etc.) indicating some interactions between the sea water and surrounding rocks. On the point of view, Masutomi springs can be classified into three categories: the equivalent ratios of SO₄ to Cl are (1) equal to, (2) more than, and (3) less than the ratio in sea water. Therefore, it suggests that dissolution or precipitation of gypsum could be occurred.

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Atmospheric aerosol samples were collected on board a vessel over the North Pacific Ocean for the period from August to October, 1985, and were analyzed for the daughter nuclides of radon, ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Po. The concentrations of ²¹⁰Pb obtained during the cruise from Hawaii to Midway were about 5 dpm/1000m³, corresponding to about one-eighth of the annual mean value observed at Okushiri Island (42°N) in Japan. On September 23, a cold front pass at a point of about 29°N, 177°W during the westward cruise. Before passing the cold front the concentration of ²¹⁰Pb was lower and the residence time of aerosols calculated from ²¹⁰Po/²¹⁰Pb was 48days and that from ²¹⁰Bi/²¹⁰Pb was about 14days, while the concentration of ²¹⁰Pb was increased and the residence time was largely shortered after the passing. These results suggest that there exists continental aerosols of longer residence time in the maritime air mass, which may be supplied from the upper atmosphere.

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