Isotopic age determinations were carried out for Jurassic siliceous shale (assigned to Bajocian by radiolarian fossils) and for, Triassic bedded chert (assigned to Anisian by radiolarians and conodonts) in Unuma, Gifu Prefecture, Central Japan. Whole-rock samples of the Jurassic shale give a Rb-Sr isochron age of 179.8 ± 5.7 Ma with an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.71011 ± 0.00036, whereas two of these Jurassic samples have K-Ar whole-rock ages of 151 and 152 Ma. For the Triassic chert, the Rb-Sr whole-rock isochron shows 211.9 ± 4.7 Ma with an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.71325 ± 0.00020, and a K-Ar whole-rock age for one of these Triassic samples is 207 ± 7 Ma. Two Rb-Sr whole-rock isochron ages indicate the time when the respective sedimentary rocks became chemically closed with regard to the Rb-Sr system. The initial ⁸⁷Sr/⁸⁶Sr ratios in both sets of rocks are higher than the contemporaneous marine ⁸⁷Sr/⁸⁶Sr ratio, suggesting the existence of an older landmass. The K-Ar ages of the Jurassic siliceous shale presumably represent the time of a later geologic event.

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Some xenolith-bearing Hoggar basanites and nephelinites possibly represent primary or near-primary magmas on account of their mg and Ni values. Simple model calculations show that they could be derived by 5–8 percent partial melting of a garnet-bearing pyrolite source. They are characterized by LREE enriched abundance patterns and by highly variable abundances of compatible and incompatible trace elements. These compositional features are compatible with derivation by small degrees of melting of an inhomogeneous mantle source recently enriched in LREE and other incompatible elements. Model calculations involving transition metal and REE contents do not support a cogenetic origin of the ultramafic xenoliths as source or residual material. Megacrysts of kaersutite, clinopyroxene, orthopyroxene, oligoclase, ilmenite and zircon are considered to represent high-pressure near-liquidus to near-solidus phases precipitated from basanitic magmas. Inconsistencies in trace element contents of some kaersutites and clinopyroxenes and host basalts suggest that these megacrysts are not strictly cognate with respect to their present hosts.

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Measurements of ³He/⁴He and ²⁰Ne/⁴He ratios in 12 CH₄-rich natural gas samples were made with a magnetic deflection mass spectrometer equipped with a metallic high-vacuum purification line. In order to check the resolving power, sensitivity and stability of the mass spectrometer, atmospheric air in Tokyo was measured repeatedly. The mean ³He/⁴He ratio in Tokyo air was (1.43 ± 0.03) × 10^-6. CH₄-rich gases with significantly high ³He/⁴He ratios were first observed in this study. The ³He/⁴He ratios for 5 natural gas samples collected from hot springs and mineral springs in inland basins were as high as (1.7–7.3) × 10^-6, probably due to the large contribution of the upper mantle-derived He. In comparison, the ³He/⁴He ratios for 2 samples from water wells distributed in coastal areas facing the Pacific Ocean and 5 samples from gas fields in the southern Kanto district were as low as ∼10^-7. Most of the He in these gases is inferred to be radiogenic and of crustal origin.

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The behaviour of rubidium, lithium, strontium and barium in superficial waters of a granitic area are compared with the behaviour of the associated major element: potassium, magnesium, calcium and potassium. Fractionation during dissolution is important for the Rb/K couple, whereas fractionation during deposition of new-formed minerals or uptake by vegetation is important for Mg/Li and K/Ba. Auxiliary minerals seem to play an important part in the relative concentrations of strontium and calcium in the waters.

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Total amino acids in marine sediments was determined by the combined use of hydrochloric acid hydrolysis (A fraction) and hydrofluoric acid treatment (B fraction). The B fraction comprised 5 to 10% of the total amino acids. The amino acid composition of B fraction indicated a characteristic feature that threonine and serine were relatively abundant. The amino acid composition of B fraction resembles that of diatom cell walls as pointed out by HECKEY et al. From this fact, it is interpreted that the B fraction originated from the diatom cell walls, not from the amino acid associated with aluminosilicate such as clay in sediments.

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