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Long‐term retention of impact crater topography on Ganymede
Author(s) -
Dombard Andrew J.,
McKin William B.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl011695
Subject(s) - impact crater , relaxation (psychology) , viscoelasticity , geology , terrain , viscosity , solar system , geophysics , astrobiology , mechanics , physics , thermodynamics , psychology , social psychology , ecology , biology
Previous analyses into viscous relaxation of impact craters on Ganymede have predicted short characteristic relaxation times (of the order of 100 Myr or less for larger craters), in disagreement with the apparent great ages of Ganymede's terrains. By applying improved understanding of rheologic parameters and initial crater shapes to a viscoelastic model, we calculate upper limit (zero heat flow) relaxation times in excess of the age of the solar system, eliminating this discrepancy. These very long relaxation times are not due to elastic effects, but are simply due to the effective viscosity of water ice at the appropriate temperatures and stresses.