2001-2002 Colloquium Series
NAU Liberal Arts (Bldg 18, Rm 135), Thursday, 24 January 2002, 4:00 PM
(Refreshments at 3:45 PM)
SOLIS PLANUM, MARS: THE "OASIS HYPOTHESIS" REVISITED
Nadine Barlow , University of Central Florida.
Abstract
The Solis Planum region of Mars is a high-elevation volcanic plain which
lies south of the Valles Marineris canyon system and east of the Tharsis
volcanic complex. In the 1970s, Earth-based photometric observations
of dust storms in this region suggested that H2O condensate clouds were
produced from a volatile-rich source located in Solis Lacus, the
low-albedo area of Solis Planum. High reflectivity radar returns of the
Solis region in the 1980s were interpreted as resulting from a seasonal
freeze-thaw cycle of H2O in the upper centimeter of regolith. These
observations led to speculation that a water-rich "oasis" exists near
the surface in Solis Planum. However, Viking Mars Atmospheric Water
Detector (MAWD) measurements did not find significant differences in
water vapor column abundances between Solis Planum and elsewhere, and
the oasis hypothesis faded from debate by the end of the 1980s. Recent
advances in the understanding of the geologic evolution of this region
combined with new high-resolution observations of geologic features
suggesting an extensive volatile reservoir underlying Solis Planum have
led our group to revisit the oasis hypothesis. Ejecta formation
simulation codes are being used to estimate the amounts of volatiles in
the substrate and measurements from the Mars Odyssey instruments should
help to confirm if H2O is concentrated in this region.
Local Host: Steve Tegler, (928) 523-9382.