The percolation of liquid iron alloy through crystalline silicates potentially played an important role during core formation in planetary bodies of the early solar system. In order to test the feasibility of percolative core formation, the effects of pressure, composition and mineral assemblage on the dihedral angle between Fe-O-S liquid and mantle minerals have been investigated from 1.5 to 23.5 GPa. Texturally-equilibrated dihedral angles increase from 54 to 106^o over this pressure range. The dihedral angle increases with pressure and closely related to the oxygen content of Fe-O-S phase, which decreases with increasing pressure, because oxygen reduces the interfacial energy of Fe-S melt. However, the effect of mineral assemblage on the dihedral angle seems to be negligible. Therefore, percolation is likely to have been the dominant core formation mechanism in small relatively-oxidised planetary bodies with a radius less than about 1300 km.

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The ultramafic volcanic rocks (meimechite and ferropicrite) and the related rocks in the Jurassic Mino-Tamba accretionary complex were geologically and petrologically studied to reveal the ancient igneous activities in the Permian ocean. The ultramafic volcanic rocks intruded into the Middle Permian chert and the Early Permian nappe-basal basalt (greenstone), and their fractionation product (basalt) erupted on the Middle Permian chert. Chemistry of the ultramafic volcanic rocks suggests that they were generated by the low-degree partial melting of peridotitic mantle with subducted oceanic crust component at high pressures (up to 5 GPa). The komatiitic basalt associated with the ferropicrite shows conspicuous olivine spinifex texture, which is the evidence for the high temperature, ultramafic parental magma. Ultramafic volcanic rocks such as meimechite and ferropicrite are rare on the Earth, but characteristically occur in LIPs (Large Igneous Provinces) such as Siberia and Ontong Java. The presence of the ultramafic volcanic rocks in the Mino-Tamba belt suggests that the greenstone in the Mino-Tamba belt is the fragments of the oceanic plateau formed in the Permian paleo-Pacific ocean, which was derived from large scale mantle plume (superplume).

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Imogolite is nano-sized tubular aluminum silicate and exists in natural soil. It is highly expected that imogolite be applied to various industrial areas, because this material has large specific surface area due to its unique shape, high affinity with water and excellent absorption capability. But imogolite does not exist in natural soil, so we have developed a large-scale synthetic method of Imogolite. In next stage, we have developed amorphous imogolite and HAS-Clay (a new type material) to improve the generation rate and adsorption performance. HAS-Clay is the mixture of two hydro-aluminum-silicates (an amorphous-material and a low-crystalline-clay) and an excellent material adsorbing water-vapor and carbon dioxide efficiently. For application, we have found that these materials can be applied to anti-dewing agent, heat exchange medium for heat pump system, adsorbent for desiccant air-conditioning system and adsorbents for carbon dioxide capture system.

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