There are two distinct points of view which might be called the ideal and realistic pictures of science: One appears to be concerned only with discovery and contemplation of truth. The other concerned with only its usefulness (practical application). Throughout any plan of scientific advance it would be necessary to keep a just proportion between fundamental and applied research and to maintain at all times the closest contact between them. In this paper the author presents three examples that show social function of geochemistry. One is the research providing the ground water pollution caused by civil engineering. The other is earthquake prediction by means of behavior of crustal gases erupted from mineral springs and active faults.
This is a review of the researches I have been conducting with my colleagues over the past 50 years. We examined geochemically behaviors of materials in several natural phenomena such as (1) groundwater movement under alluvial plains, (2) fault activities, (3) crustal movements including earthquakes, (4) geological development of the Japanese Islands relating to plate movement, (5) hydrocarbon distribution in the earth mantle, and (6) syntheses of organic materials by shock waves. For the phenomena (1), (2), (3), I have focused on the behavior of deep seated fluids such as He, Ar, H2, CO2, and CH4. For (4), I paid attention to Ti, Mn, several heavy metals, and carbonates in particularly siliceous and argillaceous sediments, and REEs in pre-Cenozoic volcanics. I pointed out the tectonochemical significance of manganese carbonate bands, manganese micronodules, hydrothermal cherts. For (5) and (6), I emphasized that existence of mantle hydrocarbons and abiological syntheses of organics have strong implication to astrochemistry and origin of life.