HR: 08:37h
AN: P21B-03    [Abstracts]
TI: Areal estimates of dune deposits in Kaiser Crater on Mars
AU: * Mullins, K F
EM: kmullins@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AU: Hayward, R K
EM: rhayward@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AU: Bourke, M
EM: mbourke@psi.edu
AF: Planetary Science Institute, 1700 E. Fort. Lowell Rd. #106, Tucson, AZ 85719-2395 United States
AU: Titus, T N
EM: ttitus@usgs.gov
AF: U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AU: Fenton, L K
AF: Arizona State University, Dept. of Geological Sciences Mail Code 1404, Tempe, AZ 85287-1404 United States
AU: Christensen, P R
EM: phil.christensen@asu.edu
AF: Arizona State University, Dept. of Geological Sciences Mail Code 1404, Tempe, AZ 85287-1404 United States
AB: Aeolian studies on Mars offer an excellent method for deciphering some of the most challenging questions regarding ongoing Martian surficial processes. A first step in understanding these processes is to produce a database of aeolian dune deposits in a global geographic context. We have begun construction of a proto-type database designed to accomplish that task using THEMIS IR images to identify, delineate (using ARCMAP), classify and archive Mars dune deposits. We have used this proto-type database to begin preliminary studies of the dune deposits in Kaiser crater on Mars. Most of the dune deposits in the crater are in one large contiguous field that is composed of several smaller areas of differing and merging morphologies. The remainder of the sand is contained in a single smaller detached field and three small craters within Kaiser crater proper. We identified 15 distinct dune deposits, drew polygons around the deposits using ARCMAP and calculated the area for each. The total areal extent of the deposits in Kaiser crater and the smaller craters within Kaiser (including dunes of unknown morphologies, sand sheets and sand bedforms) was calculated to be 2,611 km2. We then examined the dune fields within the crater and broke them into three broad categories based on dune morphology: barchan/barchanoid (BB), tranverse/complex (TC), and unknown/bedform (UB). The BB category contains seven sub-areas with a combined areal extent of 1,159 km2, the TC category has three sub-areas with a total of 1,161 km2, and the UB group has five sub-areas totaling 290 km2. The data for most of these deposits has certainly been overestimated, particularly for dune morphologies like barchans, as they tend to be isolated dunes with little to no inter-dunal sand. However, the TC category estimates are surely more accurate as the morphology allows for fewer inter-dunal areas that have little to no sand deposition. Preliminary estimates for wind direction based on observations of dune slip-face orientation for the western part of the Kaiser field are dominantly from the west with a smaller northwest, and in some cases a southwest, component as evidenced by barchan horn elongation. This elongation appears on the northern horn in the barchans in the southern deposits and on the southern horns in the barchans in the northern part of the larger contiguous Kaiser field. However, the slip-face geometry for the barchans and transverse dunes in the eastern part of the field indicate a dominant easterly wind. It is unknown at this time if the reversal is a function of topographic influences, seasonal wind change or larger climatic changes over a longer geologic period. Refinement of the slip-face orientations versus distribution and age correlations within the field are ongoing and preliminary estimates of dune deposit volume will be presented in December.
DE: 5415 Erosion and weathering
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting