Carbonates very unlikely source for CO2
From the Aldrich catalog... Calcium carbonate decomposes aroud 800 C. Sodium carbonate lists a melting point of 851 C. I believe it would have to be hotter than this to get any CO2 from the sodium carbonate.
Nevertheless, I like your theory! I thought you were going to say the volatile was water vapor, liberated by the melting of entrapped ice. Since the vapor pressure is so low, it wouldn't take much to increase it substantially.
However, I dont see why you need volatiles for this, just low gravity. Maybe they could use the vomit comet for some low G dust flow experiments.