A Catalog of Rock Abrasion Features at the Mer Landing Sites: Preliminary Results from Spirit and Comparisons with Orbital Wind Direction Indicators A

Introduction Aeolian abrasion is the dominant rock weathering mechanism on Mars. Ventifacts, defined as rocks whose shapes or textures have been modified by windblown particles, are the manifestation of this weathering mechanism and are found on Earth and Mars. Studies of ventifacts and related features at the well-traversed Spirit Mars Exploration Rover (MER) landing site provides insight into rock abrasion rates, the variability of abrasion as a function of location relative to local topography, and comparisons between the mechanisms by which abrasion operates in the Martian versus the terrestrial environment. Herein we provide a record and interpretation of results, so far, of ventifacts and related features at the Spirit landing sites using Pancam data (Figure 1). The use of MOC NA and THEMIS VIS images are also used to observe and interpret relevant wind direction features (Figure 2). Results at this point are qualitative, with quantitative analysis ongoing.