The latest results on the petrology of the upper mantle materials are reviewed. Various mantle processes can be known on two kinds of mantle fragments, xenoliths in mantle-derived magmas and solid intrusive massifs. The Horoman peridotite complex, Hokkaido, is one of the best ones from which we can learn various mantle processes.
Restites, cumulates, metasomatites and frozen melts may constitute the upper mantle. Harzburgites and lherzolites, the commonest mantle materials, are basically restites, which have been modified to various extent by metasomatism. Harzburgites, which are refractory in terms of major elements and mode, are frequently enriched with strongly incompatible trace elements, including light rare earth elements (=REE paradox). The enrichment was possibly performed by percolation of exotic fluids after consolidation of the peridotites. Dunites are not simple restites but are either cumulates from Mg-rich magmas or metasomatites which are produced by selective dissolution of pyroxenes from peridotites due to interaction with exotic melts. Podiform chromitites with dunite envelope can be formed by such mantle-magma interactions.

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Fission track age of sphene of five samples from the Hanawa pluton near the Tanakura Shear Zone, northeastern Honsyu, Japan was able to be measured by grain-by-grain method, although the number of spontaneous track (density) of sphenes is variable among rock samples and sphene crystals capable of measurement are a little among mineral grains of a sample. The ages were determined comparing with age standard sample (M. D. C., 98.7 Ma). Mineral grains were burned in a tephron resin was etched by 50M(1 M=1 mol dm^-3) NaOH(130°C) after. The spontaneous track density was measured on the polished surface and the induced track density on the mica detecter after the thermal neutron irradiation.
Since the tracks induced by ²³²Th and ²³⁸U occupy considerable amounts on the irradiation at a reacter with a low Cd ratio, age data were corrected by Th/U ratio. Th and U contents in sphene measured by NAA range from several ten to several hundred ppm corresponding to 0.089-4.0 in their ratio (Th/U). As a results of the correction by Th/U, the age data became 2% younger than before.
The ages of the mylonite-like subfacies, large sphene bearing subfacies, and fine-grained quartz diorite-tonalite facies are 67.4, 91.9 and 92.5, 92.5 and 93.1 Ma respectively. The K-Ar ages of hornblendes in large sphene-bearing subfacies are 10% younger than those of the fine-grained quartz diorite-tonalite facies (Shibata and Uchiumi, 1983), while F. T. age of sphene of both facies are consistent. This is caused by the gap of the closure temperature in both methods. More younger age (67 Ma) of the mylonite-like subfacies is probably due to shear heating effect along the Tanakura Shear Zone.

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Petrographic descriptions and mineralogical data have been presented together with analytical results of major and trace elements for tholeiitic picritic basalt-ferrobasalt suite from the Deccan plateau, India. The compositional relation between coexisting augite and pigeonite was elucidated. Wide variations of incompatible element abundances were recognized among the samples but their patterns of relative enrichments parallel one another. The rock suite was probably produced by partial melting of mantle peridotite with abundances of incompatible elements rather close to primordial abundances. However, the Sr isotopic abundances were highly variable in the source, as also were alkali and alkali earth elements to a lesser extent. Fractional crystallization under low-pressure conditions was a major process in the evolution of this rock sequence. Olivine (Fo_85-80) was predominant in the differentiation and plagioclase was probably also involved together with augite.

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Evaporites were observed on a surface of the historical brick in the Museum Meiji-Mura. Aphthitalite (K₃Na(SO₄)₂), thenardite (Na₂SO₄), trona (Na₃H (CO₃)2•2H₂O), and thermonatrite (Na₂CO3•H₂O) were identified as the main component minerals of the evaporites. These evaporates are considered to be formed in these less than a few decades under the humid climate of Japan. Because no sulfur-containing minerals can be found in the plaster nor in the bricks, it is thought that aphthitalite and thenardite were formed by the interaction between bricks and acid rain water with SO₄^2-ion. Experimental results support this idea; rain water-brick interaction has produced sulfate, whereas distilled water-brick interaction has not produced sulfate. To conserve this brick cultural property, it is desirable that roofs and gutters would be improved to prevent bricks from impregnation of rain water.

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