Spheres coming from bedrock?

If we read between lines then, it would seem that the MER project
scientists are leaning towards a palagonitized, volcaniclastic
(re-sedimented tuff/ash) origin for the bedrock, and a subsequent
diagenetic/hydrothermal alteration origin for the sulfur anomaly and
hematite-rich spherules.

... lands (bunny comes to investigate); 10) speculation ensues.


Could someone please explain or speculate for me about why the soil
structure looks so "tubular" - indeed almost segmented by miniscule
spherules - and these "tubes" have shapes of straight, curved,
self-crossing and what even appears to be "spiral" in some instances?
Perhaps that's typical of many soil structures, or it's especially so
for sulfur-rich ones, or ? Just a curious lurker here, tia..

Spirit
http://marsrovers.jpl.nasa.gov/galle...0P2953M2M1.JPG
http://marsrovers.jpl.nasa.gov/galle...0P2953M2M1.JPG

Opportunity:
http://marsrovers.jpl.nasa.gov/galle...0P2953M2M1.JPG
http://marsrovers.jpl.nasa.gov/galle...0P2953M2M1.JPG