The Occurrence and Geological Implications of Carbon Dioxide Clathrate Hydrate on Mars.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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Analysis of the temperatures and pressures at the Viking Lander 2 site VL-2 during the presence of surface ice condensate shows that the ice partially converted to carbon dioxide clathrate hydrate on at least several occasions. The occurrence of CO2 hydrate at the VL-2 latitude indicates that ground ice and surface ice at latitudes nearer the poles would convert to hydrate during the Martian winter. The conversion of ice to hydrate is shown to result in a volume expansion of 16 or - 2. The geological importance of this volume expansion, and the converse volume reduction as hydrate converts to ice, is investigated. The reduction in volume appears to be a good candidate for the cause of the chaotic terrain. A method is suggested for determining whether the melting of a buried deposit of ice or the dissociation of a buried hydrate deposit, and subsequent melting of the resulting ice, caused the chaotic terrain and associated flood channels. No quantitative measure of the force exerted by ice as it converts to hydrate was obtained. However, calculations indicate that the conversion of ice to hydrate could approach the force given by the freezing of water in confined spaces provided sufficient time is allowed for the reaction and the ice completely fills the confined space prior to conversion.