I did a summary on my site www.marsgeo.com of the chemistry and alteration that the Mars rover Spirit observed on Columbia Hills. One of the things I wanted to get other people's opinions on is concerning the origin of phosphorous, which is relatively high in the Columbia Hill rocks and outcrops.

The abstracts I read indicate that the West Spur rocks have little to no olivine while the rocks higher up in the hills have higher concentrations of olivine. This implies that the West Spur rocks have been exposed to a lot more water than the rocks at higher elevations.

How does this tie in with the relatively high phosphorours and titanium levels in rocks such as Wishstone? Is it possible that the original source rock for the P and Ti was a deeper intrusive rock, which may have come in contact with groundwater/ice? The P and Ti could've been extracted from the intrusive, gone in solution into the water and then the heat of the intrusive caused the P and Ti rich water to migrate upward and alter the volcaniclastic sequence of rocks making up Columbia Hills.

Does this sound reasonable?

Check out my write up and throw in your opinion.

Cheers,
Aldo.

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