Physics
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufm.p33b1457d&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #P33B-1457
Physics
5475 Tectonics (8149), 6225 Mars, 8138 Lithospheric Flexure, 8149 Planetary Tectonics (5475), 8164 Stresses: Crust And Lithosphere
Scientific paper
Two different models of lithospheric stress have been employed to explain the majority of the faulting in and around Tharsis. Banerdt and Golombek [2000] used topography and gravity as boundary conditions and a full thin shell treatment with horizontal gradient loads and both bending and membrane stresses, lithospheric deflection and a laterally varying crustal thickness determined through the system of shell equations by the two boundary conditions. They inferred that Tharsis was formed primarily by volcanic construction accommodated by lithospheric flexure. However, the faulting extending from Ceraunius Fossae north and north-east through Tantalus and Alba Fossae is not well described by this model. Either these structures formed under different conditions than we see today, or the assumptions of this model are not appropriate for this region. Dimitrova et al [2006] showed the deviatoric stress field associated with horizontal gradients of gravitational potential energy (GPE) alone provides an excellent fit to (~ 70%) of the normal faults as mapped by Knapmeyer et al [2006] in the region. This fit suggests that many of the faults were created at early times when elastic thicknesses and membrane and flexural stresses were small, a combination of brittle and ductile deformation was likely to be widespread, and GPE stresses dominated. We revisit the problem of the stress at the time of faulting by incorporating a new method for deriving the load function and the vertical displacement using the driving force of the difference between local pressure and global average pressure, inferred from the topography of Zuber et al [2000] and the crustal thickness model of Neumann et al [2004]. We build on the approach of Banerdt and Golombek [2000] by making no assumptions on the source or type of loading. The key point here is that the load that has lead to flexure involves an unknown radial displacement. In our approach, the problem of determining this radial displacement also implicitly involves determining the load function with no additional assumptions. Both our approach and that of Banerdt and Golombek [2000] satisfy topography and gravity, and in both cases, once the deflection is known, stress and strain are determined uniquely by the displacement field. In both models the range of vertical displacements is very similar (40km vs. 32km), and the results are similar in the areas of negative vertical displacements centered at (-140E, 20N), and (-110E, 0N) and in the areas of positive vertical displacement at (-45E, 15S), (-45E, 50S). Differences in the two solutions, including vertical displacements in our model that show larger variability at high spherical degree and order, will be evaluated using the strain model of Banerdt and Golombek [2000] and the surface fault data of Knapmeyer et al [2006].
Dimitrova Lada L.
Holt William E.
Schultz Richard A.
No associations
LandOfFree
A New Flexure-Dominated Lithospheric Stress Model for Mars, Driven by Pressure Differences at the Base of the Lithosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A New Flexure-Dominated Lithospheric Stress Model for Mars, Driven by Pressure Differences at the Base of the Lithosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A New Flexure-Dominated Lithospheric Stress Model for Mars, Driven by Pressure Differences at the Base of the Lithosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1237880