Other
Scientific paper
Apr 1999
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999jgr...104.8595b&link_type=abstract
Journal of Geophysical Research, Volume 104, Issue E4, p. 8595-8616
Other
48
Planetology: Solid Surface Planets: Erosion And Weathering, Planetology: Solar System Objects: Mars, Planetology: Solid Surface Planets: Surface Materials And Properties, Planetology: Solar System Objects: Comparative Planetology
Scientific paper
About half of the rocks at the Mars Pathfinder Ares Vallis landing site appear to be ventifacts, rocks abraded by windborne particles. Comparable resolution images taken by the Imager for Mars Pathfinder (IMP) camera and the Viking landers show that ventifacts are more abundant at the Pathfinder site. The ventifacts occur in several forms, including rocks with faceted edges, finger-like projections, elongated pits, flutes, grooves, and possible rills. The trends of elongated pits, flutes, grooves, and rills cluster at ~280-330° clockwise from north and generally dip 10-30° away from their trend direction. These orientations are indicative of southeast to northwest winds and differ from the trend of wind tails at the landing site, the direction of local wind streaks, and predictions of the Global Circulation Model, all of which indicate northeast to southwest winds. The disparity between these data sets strongly suggests that local circulation patterns have changed since the abrasion of the ventifacted rocks. The greater number of ventifacts at the Pathfinder site compared to either of the Viking sites is most easily explained as being due to a larger supply of abrading particles, composed of either sand-sized grains or indurated dust aggregates, and higher surface roughness, which should increase the momentum of saltating grains. The Pathfinder ventifacts may have formed shortly after the deposition of outflow channel sediments nearly 2 Gry ago, when a large local supply of abrading particles should have been abundant and atmospheric conditions may have been more conducive to rock abrasion from saltating grains. Based on how ventifacts form on Earth, the several ventifact forms seen at the Pathfinder site and their presence on some rocks but not on others are probably due to local airflow conditions, original rock shape, exposure duration, rock movement, and to a lesser extent, rock lithology. The abundance of ventifacts at the Pathfinder site, together with other evidence of weathering, indicates that unaltered rock surfaces are rare on Mars.
Bridges Nathan T.
Greeley Ronald
Haldemann Albert F. C.
Herkenhoff Ken E.
Kraft Markus
No associations
LandOfFree
Ventifacts at the Pathfinder landing site does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Ventifacts at the Pathfinder landing site, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ventifacts at the Pathfinder landing site will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-891206