HR: 0800h
AN: P51B-0924    [Abstracts]
TI: Topography of Beethoven and Tolstoj Basins, Mercury: Implications for Lithospheric Flexure
AU: * Andre, S L
EM: andres@si.edu
AF: Center for Earth and Planetary Studies, Smithsonian Institution, National Air and Space Museum, P.O. Box 37012, Washington, DC 20013 United States
AU: Watters, T R
EM: watterst@si.edu
AF: Center for Earth and Planetary Studies, Smithsonian Institution, National Air and Space Museum, P.O. Box 37012, Washington, DC 20013 United States
AB: Interior structures of two mercurian basins, Beethoven and Tolstoj, are characterized using topography derived from Mariner 10 stereo images. The topography of the two mercurian basins is similar to that of lunar mare-filled basins, such as Serenitatis. In addition to topography, the tectonic features within Beethoven and Tolstoj basins are compared to those of lunar basins. Beethoven and Tolstoj basins exhibit little evidence of deformation compared to Caloris basin and their lunar counterparts. Well-developed basin-concentric wrinkle ridges and arcuate graben are characteristic of many lunar basins and are thought to result from lithospheric flexure in response to the superisostatic load from the mare basalts. The presence of wrinkle ridges in the floor of Caloris basin suggests that the basin interior has undergone compression, possibly the result of subsidence of the interior fill. Because both Beethoven and Tolstoj lack basin-concentric wrinkle ridges and arcuate graben, we suggest that either Mercury's elastic lithosphere was too strong for significant lithospheric flexure and subsidence to occur, or the basin fill material provides little density contrast and thus exerts little net load on the mercurian lithosphere. Compositional evidence from color-derived parameter images of Tolstoj basin indicates that the basin fill has an FeO abundance comparable to that of average mercurian crust. This suggests that the basin fill has a similar density to the surrounding crustal material and that the load may be insufficient to induce flexure.
DE: 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS
DE: 5475 Tectonics (8149)
DE: 6235 Mercury
SC: Planetary Sciences [P]
MN: Fall Meeting 2005