HR: 1330h
AN: P42A-0423    [PDF]
TI: Rheological properties of slope streaks with anastomosing patterns on Mars
AU: * Miyamoto, H H
EM: miyamoto@geosys.t.u-tokyo.ac.jp
AF: Lunar and Planetary Laboratory, University of Arizona, 1629E University Blvd., Tucson, AZ 85721 United States
AU: * Miyamoto, H H
EM: miyamoto@geosys.t.u-tokyo.ac.jp
AF: Department of Geosystem Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 Japan
AU: Dohm, J M
AF: Department of Hydrology and Water Resources, University of Arizona, 1133E North Campus Drive, Tucson, AZ 85721 United States
AU: Beyer, R A
AF: Department of Geosystem Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 Japan
AU: Baker, V R
AF: Department of Hydrology and Water Resources, University of Arizona, 1133E North Campus Drive, Tucson, AZ 85721 United States
AB: Slope streaks have formed during the Mars Global Surveyor mission marking geologic activity at the Martian surface. Here, we present results from numerical modeling to help explain flow-like, morphologic characteristics, which include branching and anastomosing patterns influenced by local small topographic barriers. With a photoclinometric technique to estimate their sizes, numerical simulations of slow-moving plastic flows show that a fluid rheology and a short formation period are necessary to explain these features. We estimate that the typical values of a bulk viscosity and a bulk yield strength are less than 10 Pa s and less than 10 Pa, respectively (less than 1Pa s and 1Pa are more likely). The fluidity may be attributed to water-related flow with the solid content less than 20%, but a dry grain flow with extremely low cohesion and friction angle supported by dispersive pressure or lubricant such as atmosphere or subsurface discharge of gas is also possible. The continuous features of slope streaks from point sources are more easily explained by continuous discharges of material or lubricant. In this case, the estimated flow rate is less than several m$^3$/s and the flow duration estimated to be less than 1day.
DE: 5470 Surface materials and properties
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting