DPS 2001 meeting, November 2001
Session 36. Mars Surface Posters
Displayed, 9:00am Tuesday - 3:00pm Saturday, Highlighted, Friday, November 30, 2001, 9:00-10:30am, French Market Exhibit Hall

[Previous] | [Session 36] | [Next]

[36.15] The Cratering Record of the South Polar Layered Deposits of Mars

M. Koutnik, S. Byrne, B. Murray (California Institute of Technology)

The Mars Orbiter Laser Altimeter (MOLA) and the Mars Orbiter Camera (MOC) instruments aboard the Mars Global Surveyor (MGS) were used in a detailed search of a selected part of the south polar layered deposits (SPLD) for impact craters. Impact craters were identified from the MOLA shaded relief map and validated using individual MOLA tracks and MOC narrow angle (NA) images. The resultant crater population is at least four times greater than the crater population previously recognized from Viking data [Plaut, et al., 1988]. The mean exposure age of the SPLD is estimated to be 30 to 100 Ma depending on the established production model isochrons used [Herkenhoff and Plaut, 2000; Hartmann, 1999]. All of the 0.8 to 5 km diameter craters are considerably shallower than other Martian craters in the same diameter range. The timescales postulated for layer formation modulated solely by deterministic astronomically driven climatic fluctuations of approximately 105 to 106 years [Ward, 1979] are much shorter than the high mean surface exposure age for the SPLD determined in this study. Thus the surface of the SPLD included in our study likely records some previously unrecognized event in polar history that marked the end of layer formation and erosion in that area.

Hartmann, W.K., Martian Cratering VI: Crater count isochrons and evidence for recent volcanism from Mars Global Surveyor. Meteoritics & Planetary Science, 34, 167-177, 1999.

Herkenhoff, K.E., and J.J. Plaut, Surface Ages and Resurfacing Rates of the Polar Layered Deposits on Mars, Icarus, 144, 243-253, 2000.

Plaut, J.J., R. Kahn, E.A. Guiness, and R.E. Arvidson, Accumulation of Sedimentary Debris in the South Polar Region of Mars and Implications for Climate History, Icarus 75, 357-377, 1988.

Ward, W.R., Present obliquity oscillations of Mars: Fourth-order accuracy in orbital e and I, J. Geophys. Res., 84, 237-241, 1979.

[Previous] | [Session 36] | [Next]