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Resurfacing of Ganymede by Liquid-Water VolcanismA long-popular model for producing Ganymede s bright terrain involves flooding of low-lying graben with liquid water, slush, or warm, soft ice. The model suffers from major problems, however, including the absence of obvious near-surface heat sources, the negative buoyancy of liquid water, and the lack of a mechanism for confining the flows to graben floors. We show that topography - such as a global set of graben - causes subsurface (a hydrostatic) pressure gradients that can "suck" subsurface liquid water upward onto the floors of topographic lows (graben). As the low areas become full, the pressure gradients disappear and the resurfacing ceases. This provides an explanation for the observed straight dark-bright terrain boundaries: water cannot overflow the graben, so surfacing rarely embays craters and other rough topography. Subsurface liquid water must exist for the scenario to exist, of course, and is plausibly provided by tidal heating during an ancient orbital resonance. This abstract is a summary of Showman et al. recently submitted to Icarus.
Document ID
20040062007
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Showman, A. P.
(Arizona Univ. Tucson, AZ, United States)
Mosqueira, I.
(NASA Ames Research Center Moffett Field, CA, United States)
Head, J. W., III
(Brown Univ. Providence, RI, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Publication Information
Publication: Lunar and Planetary Science XXXV: Outer Solar System
Subject Category
Lunar And Planetary Science And Exploration
Distribution Limits
Public
Copyright
Public Use Permitted.
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