HR: 12:05h
AN: P12C-04    [Abstracts]
TI: A Survey of Raised Curvilinear Features in Aeolis Mensae, Mars
AU: * Enga, M
EM: mb348@nau.edu
AF: Northern Arizona University, BOX 6010, Flagstaff, AZ 86011, United States
AU: Burr, D M
EM: dburr@seti.org
AF: Carl Sagan Center, SETI Institute 515 N. Whisman Rd., Mountain View, CA 94043, United States
AB: Raised curvilinear features (RCFs) are seen on the surface of Mars in the Aeolis Mensae/western Medussae Fossae Formation. The sinuous plan form of these RCFs and their frequently networked appearance suggest their formation by some manner of aqueous flow. In order to gain a better understanding of the formation mechanisms and the hydroclimatic implications of these RCFs, we conducted a survey focused on a region spanning -8N to 4 N and 138E to 159E, centered on the two western lobes of the Medussae Fossae Formation. All THEMIS-VIS data within this region (478 images) up to the July 2007 release were examined. RCFs were then noted with a location and elevation and put into a database. Where required, THEMIS-VIS images were mosaicked to provide coverage of aerially broad or extensive RCFs and RCF networks. Based on our initial characterizations, we developed a morphological classification scheme to categorize more than 150 RCFs found in this area. The classification scheme includes five types of individual morphologies and five types of network morphologies, which have been cross-correlated, allowing us to determine the most common morphologic combinations. The RCFs range in size from small features, less than 10km in length, to large features spanning several hundred square kilometers. Their location in and around the Amazonian-aged Medusae Fossae Formation suggests that these RCFs formed during the Amazonian epoch, Mars' youngest time-stratigraphic epoch. However, possible clustering of RCFs around the margins of the western Medusae Fossae Formation lobes implies that a significant portion of these features may be located in the time- stratigraphic unit beneath the Medusae Fossae Formation, and therefore may predate the Medusae Fossae Formation. Elevational data derived from gridded Mars Orbiter Laser Altimeter (MOLA) topography indicate that these RCFs are located throughout an elevational range spanning ~2300 m, suggesting that, whenever their formation occurred, it occurred over a geologically significant period of time. Current hypotheses for the formation mechanisms of these RCFs include inverted fluvial channels and glaciofluvial eskers. Some association with impact craters is also noted, although the exact nature of that association is still unclear. Continued work will focus on determining the formation mechanisms for each class of RCF and more accurate determination of their time-stratigraphic epoch(s) of formation.
DE: 5419 Hydrology and fluvial processes
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting