Radar Sounding Evidence for Buried Glaciers in the Southern Mid-Latitudes of Mars
John W. Holt,1*
Ali Safaeinili,2
Jeffrey J. Plaut,2
James W. Head,3
Roger J. Phillips,4
Roberto Seu,5
Scott D. Kempf,1
Prateek Choudhary,1
Duncan A. Young,1
Nathaniel E. Putzig,4
Daniela Biccari,5
Yonggyu Gim2
Lobate features abutting massifs and escarpments in the middle
latitudes of Mars have been recognized in images for decades,
but their true nature has been controversial, with hypotheses
of origin such as ice-lubricated debris flows or glaciers covered
by a layer of surface debris. These models imply an ice content
ranging from minor and interstitial to massive and relatively
pure. Soundings of these deposits in the eastern Hellas region
by the Shallow Radar on the Mars Reconnaissance Orbiter reveal
radar properties entirely consistent with massive water ice,
supporting the debris-covered glacier hypothesis. The results
imply that these glaciers formed in a previous climate conducive
to glaciation at middle latitudes. Such features may collectively
represent the most extensive nonpolar ice yet recognized on
Mars.
2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
3 Department of Geological Sciences, Brown University, Box 1846, Providence, RI 02912, USA.
4 Southwest Research Institute, Boulder, CO 80302, USA.
5 INFOCOM Department, University of Rome "La Sapienza," 00184 Rome, Italy.
* To whom correspondence should be addressed. E-mail: jack{at}ig.utexas.edu
