HR: 09:44h
AN: P21B-07    [Abstracts]
TI: Aeolian Abrasion, a Dominant Erosion Agent in the Martian Environment
AU: * Bridges, N
EM: nathan.bridges@jpl.nasa.gov
AF: Jet Propulsion Laboratory, MS 183-501 4800 Oak Grove Dr., Pasadena, CA 91109 United States
AU: Cooper, G
EM: pulse@asu.edu
AF: PRISM, Arizona State University, PO Box 878609, Tempe, AZ 85287 United States
AU: Eddlemon, E
EM: eeddlemon@mail.arc.nasa.gov
AF: Mars Surface Wind Tunnel, Department of Geosciences, Arizona State University, Tempe, AZ 85287
AU: Greeley, R
EM: greeley@asu.edu
AF: Mars Surface Wind Tunnel, Department of Geosciences, Arizona State University, Tempe, AZ 85287
AU: Laity, J
EM: julie.laity@csun.edu
AF: Department of Geography, California State University, Northridge, CA 91330 United States
AU: Phoreman, J
EM: James.Phoreman@honeywell.com
AF: Mars Surface Wind Tunnel, Department of Geosciences, Arizona State University, Tempe, AZ 85287
AU: Razdan, A
EM: Razdan@asu.edu
AF: PRISM, Arizona State University, PO Box 878609, Tempe, AZ 85287 United States
AU: Van Note, S
EM: scottv@asu.edu
AF: PRISM, Arizona State University, PO Box 878609, Tempe, AZ 85287 United States
AU: White, B
EM: brwhite@ucdavis.edu
AF: Mechanical & Aeronautical Engineering, University of California, Davis, CA 95616-5294 United States
AU: Wilson, G
EM: Gregory.R.Wilson@jpl.nasa.gov
AF: Jet Propulsion Laboratory, MS 183-501 4800 Oak Grove Dr., Pasadena, CA 91109 United States
AB: Aeolian abrasion is one of the predominant erosion mechanisms on Mars today. Martian ventifacts record the climate under which the rocks were modified (wind direction, wind speeds and particle flux) and therefore tie into the overall climatic regime of the planet. By better understanding the rates at which rocks abrade and the features diagnostic of specific climatic conditions, we can gain insight into past climates. Herein we report on numerical models, wind tunnel experiments, and field work to determine 1) Particle and kinetic fluxes on Earth and Mars, 2) the degree to which these parameters control abrasion, and 3) how, in detail, rocks of various shapes and compositions erode over time. Kinetic energy generally increases with height, whereas flux decreases, and impact angles, which affect energy transfer, and rebound effects are functions of the rock facet angle. This results in a non-linear relationship between abrasion potential and height that is a function of wind speed, planetary environment, and target geometry. We have computed the first three of these parameters numerically using a numerical saltation code, combined with published flux calculations These results have been compared to wind tunnel tests of flux vs. height, abrasion of erodible targets, and high speed video analysis under terrestrial and Martian pressures. We are also using high resolution laser scanning to characterize textures, shapes, and weathering changes for terrestrial and Martian rocks at the 100s of microns scale. We find that facet angle, texture, and rock heterogeneity are of critical importance in determining the rate and style of abrasion. Field and theoretical results demonstrate that high speed winds, not the integrated flux of lower speeds, and sand, not dust, produce most rock abrasion. On Mars, this requires sustained winds above 20-25 m/s at the near surface, a challenge in the current environment.
DE: 5415 Erosion and weathering
DE: 5445 Meteorology (3346)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting