3 degrees per thousand feet, (adiabatic lapse rate),

More coolness, discussions of pressure in deep mines (as regards biology) taught me about hydrostatic equilibrium and barometric formulas, and now we have the thermodynamics of the atmosphere.

Just checking the units; seeing that we have low pressure and temperature, I will make a wild guess that it doesn't matter much whether one uses the dry or saturated lapse rate, making using the dry rate so much more robust. So, at Mars gravity that would be ~ 3 Celsius/km or ~ 2 Fahrenheit/1000 feet. The above is all in imperial units then.

I don't have the chops to check if there will be potential for liquids (but I see some reference papers that could teach me I guess): "'Liquid water is typically stable at the lowest elevations and at low latitudes on the planet because the atmospheric pressure is greater than the vapor pressure of water and surface temperatures in equatorial regions can reach 273 K for parts of the day [Haberle et al., 2001]'"

So Mars isn't only incredibly cool, it has hotness as well.

And yes indeed, on the suggested expedition. Though, if Phoenix uncovers evidence of liquid water episodes associated with the current nature of the polar regions, I have to wonder if a deep valley expedition will be a high priority at first.

Now take this news and relate it to the deep valleys where the temperature will rise by 3 degrees per thousand feet, (adiabatic lapse rate), as you descend and we can see there is the clear potential for liquid water at the bottom of some of the deep valleys.

We need an expedition to the bottom of one to discover if this would be correct.