Erosion rates on Mars and implications for climate change: Constraints from the Pathfinder landing site

• Published in: Journal of Geophysical Research 2000-01, Vol.105 (E1), p.1841-1853
• Main Authors: Golombek, M. P., Bridges, N. T.
• Format: Article
• Language: English
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/1999JE001043

The observation that the Mars Pathfinder landing site looks very similar to its appearance after it was deposited by catastrophic floods around 1.8–3.5 Ga allows quantitative constraints to be placed on the rate of change of the site since that time. The abundance of erosional features such as an exhumed former soil horizon, sculpted wind tails, ripplelike and other lag deposits, and ventifacts (fluted and grooved rocks) all suggest the site has undergone net deflation or loss of 3–7 cm of material. The presence of barchan dunes and ventifacts argues for erosion by saltating crystalline sand‐size particles entrained in the wind. Most ventifacts probably formed soon after the catastrophic flood, which likely introduced a large, fresh supply of sand‐size particles distributed across the rocky plain. The strongest winds blew toward the northwest during this time, resulting in the sculpting of ventifacts, deflation of the surface, collections of dunes within Big Crater and other lows, and possibly preferentially eroding small crater rims. The predominant wind direction changed to blow toward the southwest, similar to today. These winds further deflated the surface, completed the deposition of sand‐size material in dunes and ultimately trapped these dunes in lows. The erosional features observed by Pathfinder indicate extremely low longterm deflation rates of 0.01–0.04 nm/yr since the end of the Hesperian (1.8–3.5 Ga) similar to less precise rates of