HR: 0830h
AN: P41A-0392    [PDF]
TI: Balanced crustal cross sections across wrinkle ridges on Solis Planum, Mars, from MOLA topography
AU: * Vidal, A
EM: arwen.vidal@colorado.edu
AF: Department of Geological Sciences, University of Colorado, Campus Box 399 2200 Colorado Ave., Boulder, CO 80309-039 United States
AU: Mueller, K
EM: karl.mueller@colorado.edu
AF: Department of Geological Sciences, University of Colorado, Campus Box 399 2200 Colorado Ave., Boulder, CO 80309-039 United States
AU: Golombek, M P
EM: mgolombek@jpl.nasa.gov
AF: Jet Propulsion Laboratory, Mail Stop 183-501 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: Models based on MOLA (Mars Orbiter Laser Altimeter) topographic data and Earth analogs indicate that wrinkle ridges are the surface expressions of folds that overlie blind thrust faults that collectively accommodate low bulk strains in comparison to terrestrial fold and thrust belts. Previous work based on elevation offsets across ridges and their backlimb geometry suggest blind thrusts on Solis Planum penetrate deeply into the Martian crust. As a continuation of this work, we undertook axial surface mapping and forward and inverse modeling of wrinkle ridge on Solis Planum using topographic data from MOLA in order to better constrain fault geometry and the depth at which thrust faults flatten. First and second derivative slope maps constructed along transects perpendicular to ridges on Solis Planum suggest wrinkle ridges there are defined by very gently curved (concave upward) and wide (~10 km) backlimbs. We interpret these backlimbs as forming by uplift above listric blind thrusts that steepen towards the surface. Our maps also indicate that sharp bends are not present in backlimbs, suggesting that sharp bends in underlying thrusts are not present. The along-strike geometry of forelimbs of these ridges are interpreted as the surface expression of fault-propagation folds. Topographic profiles perpendicular to the strike of folds on Solis Planum yielded raw profiles, linearly detrended with respect to regional slope, and first and second derivative slopes were calculated. These topographic profiles and estimates for crustal thickness are then input into forward and inverse models in order to constrain the optimal depth to detachment and fault curvature for blind thrusts in Solis Planum.
DE: 5475 Tectonics (8149)
DE: 6225 Mars
DE: 8010 Fractures and faults
DE: 8149 Planetary tectonics (5475)
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting