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Numerical Simulations of Non-Newtonian Convection in Ice: Application to EuropaNumerical simulations of solid state convection in Europa's ice shell have so far been limited to consideration of Newtonian flow laws, where the viscosity of ice is strongly dependent upon temperature, predicting that a stagnant lid should form at the top (10-40%) of a convecting ice shell. Such large thicknesses seem to contradict estimates of the effective elastic thickness of Europa s ice shell during its geologically active period. Recent laboratory experiments characterize the rheology of ice as the sum of contributions from several temperature and strain rate-dependent creep mechanisms. We present the results of numerical simulations of convection within Europa s ice shell using the finite-element model Citcom, applying the non-Newtonian rheology of grain boundry sliding. Our calculations suggest a shallower brittle/ductile transition and larger interior convective velocities compared to Newtonian rheology. The flow field is time-dependent, with small, localized upwellings and downwellings at the thermal boundary layers that have minimal topographic expression at the surface.
Document ID
20030110940
Document Type
Conference Paper
Authors
Barr, A. C. (Colorado Univ. Boulder, CO, United States)
Pappalardo, R. T. (Colorado Univ. Boulder, CO, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Lunar and Planetary Science XXXIV
Subject Category
Lunar and Planetary Science and Exploration
Funding Number(s)
CONTRACT_GRANT: NGT5-50337
CONTRACT_GRANT: NCC2-1340
Distribution Limits
Public
Copyright
Public Use Permitted.

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