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https://hdl.handle.net/2115/35632

In-Situ Observations of Growth Process of Clathrate Air-Hydrates Under Hydrostatic Pressure

英語

1992

Hokkaido University Press

7th International Symposium on the Physics and Chemistry of Ice. 1-6 September 1991. Sapporo, Japan

The optical microscopic observations of the growth processes of air-hydrate crystals from air bubbles included in deep ice cores were carried out under high hydrostatic pressure. The transformation from a bubble to an air-hydrate crystal occurred when the annealing pressure was higher than the theoretical one of the air-hydrate dissociation. The growth patterns of the crystal could be classified into two types. The crystal growth rates were measured using the microscopic images and they related linearly to the excess pressure over the dissociation one at each annealing temperature. The relation indicates that the rate-determining process of the crystal growth is mainly the flux of air and water molecules to the crystal surface. The observed two different growth patterns can be explained in terms of the supply processes of water molecules to the surface.

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