Could it really have been mud seen earlier by Spirit?

Yen A. S. * Ming D. W. Gellert R. Clark B. C. Morris R. V. Rodionov D.
Schröder C. Klingelhöfer G.
Subsurface Weathering of Rocks and Soils at Gusev Crater [#1571].
"Data collected from Spirit at Gusev Crater suggest that enhanced
weathering of rocks and soils occurs beneath the immediate surface. We
believe that this alteration is a result of diurnal condensation of
thin-films of water on subsurface materials."
www.lpi.usra.edu...


This abstract to the upcoming 36th Lunar and Planetary Science Conference argues that thin liquid water films are currently forming subsurface in Gusev.
Then perhaps the overlying cover could have reduced evaporation to allow mud to form.

cf.,

Newsgroups: sci.astro, alt.sci.planetary, sci.physics, sci.geo.geology, sci.geo.meteorology
From: "Robert Clark"
Date: 25 Dec 2004 12:58:34 -0800
Local: Sat, Dec 25 2004 12:58 pm
Subject: More on "Frost on the rover solar panels".
groups-beta.google.com...


Bob Clark

It would take a lot more that thin films of water on subsurface (underground) materials to produce mud on the surface, so no, it was not mud that the rovers photographed.

This should be posted in one of the numerous "mud" threads already existing.