Gases and rocks along several active faults in central Japan were analyzed to understand their chemical characteristics and to collect information on gases at depth which are useful for the geochemical earthquake prediction. The gases along fault zones possess chemically different characters according to their mode of occurrence. (1) Gases charged mainly within fault gouges (Type I) are characterized by high concentrations of H₂ and CO₂ and lack CH₄. CO₂ issues mainly through the intensely sheared zone of a fault where fracturing of rocks is most common. He/Ar ratio calculated to be high in the lithospheric airs at depth, however, is not always high in Type I gases. (2) Gases occurring as bubbles in flowing mineral waters from fault zones (Type II) show high concentrations of He and CH₄; they generally lack CO₂. The mineral waters examined are usually of high alkalinity and hence CO₂, if generated at depth, will be dissolved in the water during uprising. There exists a correlation between CH₄ content and N₂/Ar ratio in Type II gases collected over a wide area of the Ryoke metamorphic terrane consisting mainly of granitic rocks, suggesting some unique source of CH₄ and N₂ within the examined area. Hydrogen is rarely found in Type II gases but sometimes appears intermittently, suggesting that H₂ in Type II gases is not useful for the earthquake prediction, although the concentration in Type I gases might have a relation to fault activity. Fault gouges as well as brecciated rocks in fault zones extremely lose their calcium but retain ferrous iron. This variation trend of these elements during the pulverization under fault movements is different from that of the ordinary weathering. This feature can be attributed to some peculiar environment resulted from the chemical interaction among waters, gases and rocks in the fault zones. Acid fluids formed by CO₂ and water charged in the fault zones will break feldspars in parent rocks and dissolve out calcium in them, whereas H₂ will prevent iron from oxidation.

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The selective chemical leaching of cadmium, copper, manganese and iron from various minerals has been examined in the laboratory experiment. And the selective leaching technique has been applied to marine sediments to elucidate the role of clay minerals as a scavenger chiefly for cadmium in the sea. The obtained results show that clay minerals assume some significant role for the removal of cadmium from seawater.

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The Rb, Sr contents and ⁸⁷Sr/⁸⁶Sr ratios were studied for mafic and ultramafic inclusions (four lherzolites, six gabbros and amphibolites) and their host basaltic rocks from Itinome-gata, Northeast Japan. These lherzolites are relatively depleted in both Rb and Sr as compared with similar inclusions from other regions in the world. It is noteworthy that three of four lherzolites show significantly higher ⁸⁷Sr/⁸⁶Sr ratios (0.7044-0.7053) than those of host basaltic rocks (0.7030-0.7033), suggesting an accidental origin for these inclusions. However, one lherzolite is isotopically similar to the host rocks and may be related to the recent magma genesis in this region. The mafic inclusions are characterized by relatively low Rb contents (0.3 ∼ 1.8ppm), and amphibolites show ⁸⁷Sr/⁸⁶Sr ratios (0.7030-0.7032) similar to that of host basaltic rocks, but other gabbroic rocks show higher ⁸⁷Sr/⁸⁶Sr ratios (0.7035∼0.7048). These results suggest vertical inhomogeneities of the uppermost part of the mantle and lower crust in the Itinome-gata region with respect to Sr isotopes.

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Nutrient profiles in Southwest Pacific interstitial solutions suggest that in environments of oxic pelagic sedimentation microbially mediated nitrification is recognizable as a two-step process. During the first step partially oxidized nitrogenous intermediaries accumulate in distinctive ammonia and nitrite maxima along with nitrate. During the second step nitrification continues and all intermediate species are fully oxidized to nitrate. Both steps occur within a zone that corresponds in thickness to the biologically active surface layer. Similarly, experimental nitrogen regeneration from decomposition of plankton in seawater (VON BRAND and RAKESTRAW, 1941: VON BRAND et al., 1942) suggests that each step corresponds to a distinct reaction in the microbially mediated transformation of N-org → NH₃ → NO₂ → NO₃. The resolution of distinct reaction zones in pore water nutrient profiles possibly depends on the nature and mode of supply of the organic matter undergoing nitrification or reflects the spatial succession downcore of microbial populations capable of deamination, ammonium oxidation and nitrite oxidation, respectively. Finally, stoichiometric ratios of nutrients in the free water column - here demonstrated on published data from Saanich Inlet - reflect the same two steps of nitrification as delineated by the dissolved pore water species. Future pore water studies should include dissolved oxygen measurements as well as accurate ∑CO₂, PO₄ and nitrogenous species profiles, to verify and better quantify these separate steps in nitrification mechanism of oxic pelagic sediments.

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Isotopic compositions of He and elemental abundance of rare gases were determined in 7 fumarolic gas samples of the Showa-shinzan volcano collected during 1958 to 1977 and in one gas sample collected in 1978 from the Usu volcano. ³He/⁴He and ⁴He/²⁰Ne ratios were significantly higher than those for the atmospheric rare gases. This suggests a mantle He emanation. These ratios decreased and approached the atmospheric ratios with time, in harmony with the decline of the volcanic activity of the Showa-shinzan. The decrease can be accounted for by the increase in the atmospheric contamination. Estimation of He permeation through a glass wall shows that the permeation is so small that a borosilicate glass flask can preserve the initial ³He/⁴He and ⁴He/²⁰Ne ratios even though the gas sample has been stored for a long time of about 20 years. The gas sample from the Usu volcano 2km west of the Showa-shinzan, collected 14 months after the eruption of the volcano, showed the highest ³He/⁴He and ⁴He/²⁰Ne ratios of the gas samples studied. However, the gas sample from the Showa-shinzan collected immediately after the eruption of the Usu volcano showed no sign of increase in ³He/⁴He and ⁴He/²⁰Ne ratios. This suggests that the eruption of the Usu volcano did not affect the degassing of He from the Showa-shinzan, and the intrusion of lava was quite restricted.

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