posted on Jul, 14 2003 @ 12:27 AM
I believe it to likely be wind and rain as well.
The clay depicted in these photos are highly "fat" or expansive when they absorb water. This is evidenced by the fact that they crack extensively
Such "fat" clays normally produce a VERY slippery mud when they are hydrated. Also, in the photos, you can see that the trails the rocks leave are
very contoured and up close the clay appares to be somewhat molded as the rock passes over it. If there was some kind of movement while the clay was
dessicated, it would basically shatter, leaving far more ragged trails.
Yes, 700 pound rocks are a load to move... but have you ever been to warehouse store like Sams, and seen the stockers moving pallets of product on
pallet jacks? I have personally moved 500 pound loads with such a jack with one hand... simply by eliminating the friction. In a rain storm, where the
clay would be readily saturated and wind gusts up to say 40 mph, given the pretty flat terrain, I could see these things go sailing for pretty long
Darage, I doubt that these rocks would sink at all. These clays have very high compressive strength, and becase they are highly hydrophillic (water
loving), the top layer of clay will likely absorb most of the water and turn to mud, while the layer just an inch deep will remain bone dry, giving a
very robust support to weight.