Mars Polar Terrain:Studies of Ice-Soil Mixtures

The polar layered deposits (PLD) of Mars are thought to hold information on the recent climate history of Mars.  Based on crater counts, the inferred age of the PLD in the north is only ~100 kyr, while the inferred age of the south PLD is significantly greater, around 10 Ma.  It has been shown that the layered appearance of the PLD is due both to albedo and topography rather than compositional variations.  However, it is widely expected that compositional variations will be present at some level.  These compositional variations could hold clues to such things as variations in dust deposition patterns, possible volcanic activity, or changes in atmospheric or climate conditions.

Because of the importance of the PLD to Mars studies, we are characterizing the capabilities of LIBS to analyze varying mixtures of soil and ices.  Our goals are to i) study the molecular OH band present in the LIBS spectrum at high water ice contents, ii) develop calibration curves for varying ice-to-dust ratios, iii) understand how the presence of ice affects other parameters such as the detection limits for various elements present in the dust, and iv) determine depth profiling capabilities in mixed dust-ice compositions.  The results have been submitted for publication. [Publications].

LIBS was an essential part of the payload for a proposed Mars Scout mission led by Dr. Chris McKay (NASA AMES) in which a rover would have been used to explore the PLD.

On the left, a topographic view of Mars north pole, comprised of data from the Mars Orbital Laser Altimeter, an instrument on the Mars Global Surveyor (MGS) spacecraft. Image courtesy NASA/MOLA Science Team.  On the right, a Viking 2 orbiter color mosaic of the south pole of Mars.  Image courtesy NASA/NSSDC