HR: 10:35h
AN: P22A-02    [Abstracts]
TI: Evidence for Long-term Wind Modification of the Martian Surface
AU: * Catling, D C
EM: davidc@atmos.washington.edu
AF: University of Washington, Dept. of Atmospheric Sciences, Box 351640,, Seattle, WA 98195-1640 United States
AU: Wood, S E
EM: sewood@atmos.washington.edu
AF: University of Washington, Dept. of Atmospheric Sciences, Box 351640,, Seattle, WA 98195-1640 United States
AU: Leovy, C
EM: conwayt@atmos.washington.edu
AF: University of Washington, Dept. of Atmospheric Sciences, Box 351640,, Seattle, WA 98195-1640 United States
AU: Ginder, E A
EM: eginder@u.washington.edu
AF: University of Washington, Dept. of Atmospheric Sciences, Box 351640,, Seattle, WA 98195-1640 United States
AU: Louie, M
EM: mkql@u.washington.edu
AF: University of Washington, Dept. of Atmospheric Sciences, Box 351640,, Seattle, WA 98195-1640 United States
AB: General Circulation Models predict that wind erosion and deposition are persistent in certain areas on Mars regardless of long-term changes in orbital dynamics. When integrated over billion-year time scales, seemingly trivial rates of erosion or deposition $\sim$micron/yr can result in substantial surface alteration of order $\sim$km depth. This is important for interpreting Martian surface evolution. Acting on regolith over billions of years, wind could massively scour or bury landscapes, confusing the timing of events and the interpretation of features thought to be altered by interaction with volatiles. There are several indicators of whether surfaces are undergoing erosion or burial including wind streaks, the presence of bedforms and dunes, and the preservation state of small (20-2000 m) craters. The state of small craters is particularly diagnostic and their absence in a Mars Orbiter Camera narrow angle (NA) image suggests a surface age $<$9 m.y. either due to complete erosion or burial. We find that erosional and burial states of surface features inferred primarily from imaging data correlate with thermal inertia values and GCM-predicted regions of persistent deposition (e.g., Amazonis, Arabia) and erosion (e.g., Isidis, Acidalia). Small craters are also often absent between 60-80 deg latitude in both hemispheres, perhaps correlating with high wintertime wind stress. Similarly 70-95% of NA images on the Hellas floor lack small craters perhaps due to pressure-enhanced wind stress. Overall, results support the hypothesis that long-term geomorphologic action of wind has substantially altered the surface of Mars.
DE: 5415 Erosion and weathering
DE: 5445 Meteorology (3346)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting