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