HR: 0830h
AN: P21B-0054    [PDF]
TI: Gray Hematite Distribution within Valles Marineris
AU: * Weitz, C
EM: cweitz@hq.nasa.gov
AF: Planetary Science Institute, 1700 E. Fort Lowell Suite 106, Tucson, AZ 85719 United States
AU: Lane, M
EM: melissalane@cox.net
AF: Planetary Science Institute, 1700 E. Fort Lowell Suite 106, Tucson, AZ 85719 United States
AU: Anderson, F S
EM: anderson@higp.hawaii.edu
AF: University of Hawai'i at Manoa, Hawai'i Institute of Geophysics and Planetology 1680 East-West Road, POST 526B, Honolulu, HI 96822 United States
AB: Valles Marineris is one of three regions on Mars where TES has identified gray crystalline hematite. In the other two locations, Meridiani Planum and Aram Chaos, a strong correlation between the hematite distribution and geologic units has been found. We have used MOC, THEMIS, and MOLA data to determine if a similar correlation exists for hematite within Valles Marineris. After studying the larger patches of hematite within the canyons, we find a correlation between hematite abundance and distinctive geologic units for some patches, but not all. In Ophir and Candor Chasma, the hematite correlates to relatively brighter, dustier units in daytime THEMIS infrared images, but the correlation is moderate and other units with similar infrared properties have no corresponding hematite. Using the narrow angle MOC images, we have determined that the hematite signatures correspond to areas where patches of brighter material are exposed from beneath overlying dark units and dunes. This type of exhumation is similar to the hematite unit at Meridiani Planum. In Eos and Capri Chasma, the hematite appears to cross over geologic units seen in the THEMIS data sets, but no MOC images are available to assess the geology at the higher resolution. The presence of hematite also varies widely with topography, with one patch of hematite occurring across 2 km of relief in central Candor Chasma. In general, hematite occurs more prevalently on the canyon floors adjacent to the interior layered deposits, rather than on the layered deposits themselves. Our current results are based upon the hematite distribution map of Christensen et al. [J. Geophys. Res., 105, 9623-9642, 2000] but we hope to refine these TES compositional maps in order to more precisely correlate hematite to geologic features seen in the MOC and THEMIS data sets.
DE: 5410 Composition
DE: 5464 Remote sensing
DE: 5499 General or miscellaneous
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting