貝殻を構成するアラゴナイトの熱的変化について

概要

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The writer tried some experiments on the alteration of the shell composing aragonite under various temperatures and pressures. The former ranged from 100℃ to 400℃, and the latter from normal to about 700 kg/cm^2. He used specimens of recent and fossil Glycymeris yessoensis and the nacreous layer of Pinctada martensii as materials. Each powder samples were kept in the hydrothermal synthesis aparatus for three hours. As a result of the experiments, follows can be said; 1) The rate of transformation (aragonite to calcite) is remarkably accelerated under the pressure of 50-100 kg/cm^2 in comparison with the rate under normal pressure. 2) But, this tendency becomes not so distinguishable under the pressures above 100-200 kg/cm^2. 3) The plotted patterns of "aragonite only" (not altered), "aragonite-calcite mixture" (partially altered) and "calcite only" (completely altered) are not uniform in each samples. 4) The DTA curve of Pinctada is obviously diferent from those of recent and fossil Glycymeris. It can not be concluded here whether such differences of thermal characteristics among these samples are significant in biological problems of these molluscan shells or not.
地学団体研究会の論文
1973-01-25