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Goodman, J. C. and G. C. Collins, Flow of Warm Ice in a Melt-Through Model of Europa?s Ice Shell, in preparation, 2006
Melting of patches of Europa?s ice shell by a localized basal heat source has been proposed to explain the formation of chaos and lenticulae on Europa. We have constructed a model for this process which includes thermal diffusion, viscous flow of ice into the melt hole, and isostatic compensation for both thickness and density anomalies. Local heating of 4 GW or more is sufficient to melt through the bulk of an ice sheet 12-26 km thick, leaving only a thin crust tens or hundreds of meters thick. When the heat source is removed, warm ice at the base of the ice shell rapidly flows to fill in the melt hole, but its buoyancy is insufficient to cause surface uplift. Local heating of 1 GW or less is balanced by inflowing ice, and ?melt through? never occurs. Our melt-through model cannot reproduce the small diameter or positive surface relief of many lenticulae. |
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