HR: 1340h
AN: H33C-1393    [Abstracts]
TI: Properties of Martian Highlands Drainage From THEMIS Images and MOLA Topography
AU: * Stepinski, T F
EM: tom@lpi.usra.edu
AF: Lunar and Planetary Institute, 3600 Bay Area Blvd., , TX 77058, USA., Houston, TX 77058 United States
AU: Carriere, M
EM: mel_carriere@hotmail.com
AF: Queen's Univ., Dept. of Physics, Kingston, ON K7L 3N6 Canada
AU: Molloy, I
EM: imolloy@cs.purdue.edu
AF: Purdue Univ., Dept. of Computer Sci., West Lafayette, IN 47907 United States
AB: Valley networks, the river-like features common in Martian highlands, are mapped from mosaics composed of 100 m/pixel THEMIS daytime images for eight ~ 10⁵ km² Noachian sites. The resultant site's drainage density is 0.05 -- 0.1 km^-1, in agreement with the results of previous mapping based on lower resolution images. The sites are subdivided into individual drainage basins using MOLA-based, 500 m/pixel DEMs co-registered with image mosaics. Together, there are 83 non-crater basins having areas >10³ km². The following terrain parameters are calculated for each basin: area, drainage density, average elevation, relief, slope. Drainage density for individual basins is 0 -- 0.29 km^-1. There is a moderate (r=0.5) correlation between values of drainage density and relief, no other terrain parameters are correlated. Within a given site, the basins show evidence of past integration disrupted by subsequent cratering. Morphologically, the basins are divided into 5 classes on the basis of similarity between their circularity functions. There is no clear correlation between basin's morphologic class and the value of any of the terrain parameters. In particular, heavily dissected and undissected basins are found in all morphological classes. The major conclusions are as follows. 1) Higher resolution images do not reveal an existence of small-scale valleys, the drainage density of Martian highlands is likely to be fixed at ~ 0.1 km^-1. 2) The relief appears to be the only variable that statistically controls the degree of basin dissection. 3) Whatever fluvial process was responsible for valley networks formation, its associated erosion was not strong enough to control the morphology of drainage basins.
DE: 1804 Catchment
DE: 1815 Erosion
DE: 1825 Geomorphology: fluvial (1625)
DE: 5415 Erosion and weathering
SC: Hydrology [H]
MN: Fall Meeting 2005