Posted by Bill Hartmann, Planetary Science Institute, Tucson, Arizona, USA.
(Re-posted from IAG Image of the month, March 2007)
This high-resolution MGS MOC image shows overlapping landslide deposits at the foot of the wall in the Ganges region of the Valles Marineris canyon complex on Mars.
Researchers are investigating how to use the landslide data to examine the time behavior of cratering on Mars, and the implications for using small craters to date landform features. The younger (overlying) debris fan has a distinctly lower crater density of small craters than the older (underlying) deposit. The relationship shown here argues against recent suggestions that crater densities of small craters are so completely dominated by statistical clustering of “secondary” ejecta craters that they are inappropriate for dating.
C. Quantin, P. Allemand, N. Mangold and C. Delacourt, Ages of Valles Marineris (Mars) landslides and implications for canyon history, Icarus172(2), 555-572, 2004.
C. Quantin, P. Allemand and C. Delacourt, Morphology and geometry of Valles Marineris landslides, Planetary and Space Science52(11), 1011-1022, 2004.
C. Quantin, N. Mangold, W.K. Hartmann and P. Allemand, Possible long-term decline in impact rates. 1. Martian geological data, Icarus186(1), 1-10, 2007.
W.K. Hartmann, C. Quantin and N. Mangold, Possible long-term decline in impact rates. 2. Lunar impact-melt data regarding impact history, Icarus186(1), 11-23, 2007.