[X] My Assistant

[dot.dk]

In this Space.com article Steve Squyres explains how the soil Spirit has churned up lately contains a large amount of sulfates.

http://www.space.com/missionlaunches/mars_meteor_050219.html

That's interesting

[TheChemist]

We haven't seen, or heard, much about the salty soil for almost 200 sols, but it seems that Spirit may be seeing this material again, up on the peak of Husband Hill.

Thanks for sharing that slinted, quite interesting ! If it is magnesium sulfate, as in previous locations, then we have a water marker on top of the hill.
Is it a case of "deep waters" ? Or rather the soil on top of the hill was brought up from lower through geologic phenomena ?
Although I secretly hope for the first, probably the second is true

[slinted]

One piece of the puzzle that wasn't answered back at Paso Robles is what form the sulfates take. Are they concentrated in small grains, or just a major consituitant of soil in general? We've seen lots of locations, especially back down on the West Spur, where it looked like there were small brittle pebbles being crushed under the wheels exposing the bright material. For the Paso Robles trench, they churned up so much material that it became a mix which then tested very high for magnisium sulfate.

If there are salt pebbles, they might just be transported from other locations up to the peak (via the 'short distance transport' mentioned recently by JPL in relation to the grain size of sands in the Cliffhanger drift trench). But as far as I know, where the sulfates were originally deposited is still a mystery.