Recent research presented at the October Geological Society of America meeting suggests there could be relict ice in Arsia Mons on Mars due to cold based glaciers:

Earth-based Analogs of Mars Offer Insight into the Red Planet
By Leonard David
Senior Space Writer
posted: 09:45 am ET
30 October 2002
http://www.space.com/scienceastronomy/mars_earth_021030.html

Paper No. 77-10
MOUNTAIN GLACIERS ON MARS?: WESTERN ARSIA FLANK DEPOSITS INTERPRETED AS COLD-BASED GLACIAL MORAINES AND ROCK GLACIERS
http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_43170.htm

Johann Helgason had earlier argued that there is near surface ice due to glaciers in the Tharsis region:

Does Mars Hide Vast Water Deposits?
by Johann Helgason
Reykjavik - June 10, 2000
http://spacedaily.com/news/mars-water-99b.html

This receives support from the Mars Odyssey GRS readings that show ice deposits in the Tharsis low-latitude region as well as in the expected mid to high latitudes on Mars.
It is also notable that Tharsis is one of the areas that showed anomalously high water vapor readings from the Viking orbiters:

Title: Remote sensing evidence for regolith water vapor sources on Mars.
Authors: Huguenin, R. L.; Clifford, S. M.
"A survey of ground-based and spacecraft observations at visible wavelengths of condensate activity in the Martian atmosphere is presented. The observations reveal that Solis Lacus has been a center of condensate activity
throughout the observational record, along with sites in Noachis-Hellespontus and in border regions in Syrtis Major. The condensate activity did not appear to be
controlled by the distribution of aerosol dust, surface albedo, thermal inertia, or topography. Rather, the patterns of cloud and fog occurrence, together with
observed and inferred surface winds, point to these sites as primary H2O vapor source regions for condensate
development. Specifically, it is proposed (1) that the unusual distribution of condensates around Solis Lacus at
the onset of the 1973 dust storm may have resulted from the transport of moisture from the central plume site in
northern Solis Lacus (near Sinai Planum) by prevailing daytime winds and nighttime drainage winds, (2) that the
recurrent winter Tharsis and Hellas condensate features may have developed from MOISTURE DERIVED PRIMARILY FROM THE UPWIND SOLIS LACUS AND NOACHIS-HELLESPONTUS SOURCE REGIONS, respectively, and (3) that the recurrent summer Elysium clouds may have developed as a result of MOISTURE FROM UPWIND SYRTIS MAJOR BORDER SITES. The estimated
outgassing rate from Solis Lacus during 1973 was ~10^-1 km^3 yr^-1, and a similar rate is suggested for the
Noachis-Hellespontus site. These rates would probably not be high enough to be detected by the Viking MAWD experiment, but they extrapolate to the possile loss of a meter of ice from the sites in only 10^3 years. IT IS
PROPOSED THAT THE ICE IS PRESENT IN THE SURFACE LAYER AND THAT IT COULD UNDERGO MELTING DURING A PORTION OF THE DAY OVER AN APPRECIABLE FRACTION OF THE YEAR. RADAR, THERMAL, AND WATER VAPOR DATA WOULD BE CONSISTENT WITH THE
POSSIBLE OCCURRENCE OF SOIL MOISTURE AT THESE SITES."
[emphasis added]
Journal of Geophysical Research, vol. 87, no. B12, Nov. 30, 1982, p. 10227-10251.

Links to other abstracts to the Planetary Geology section of the GSA meeting can be found here:

Session No. 77 Monday, October 28, 2002
--------------------------------------------------------------------------------
8:00 AM-12:00 PM, Colorado Convention Center: A108/110
T90. Terrestrial Approaches to Extraterrestrial Problems and Vice Versa
http://gsa.confex.com/gsa/2002AM/finalprogram/session_2703.htm

Bob Clark