Origyptian Wrote:
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> I think this is the most damning part of that
> story. There is no logical scenario in which a
> cart would follow the exact same
> path to make such clearly defined ruts. Rather,
> any ruts caused by many thousands of cart runs
> long such a terrain would leave broad, shallow
> valleys around the tracks that represent the
> slight deviation from an exact path. Such broad
> shallow recesses would gradually slip into a
> central deeper rut as additional cart runs ensue,
> but that's not what we see. There is also no
> evidence of any beast of burden having applied any
> traction to the bedrock representing an effort to
> haul such huge weights that would cause that kind
> of 'erosion' into such stone. So what's the energy
> source of the authors' model?

One of my biggest problems with the calculations in that paper was the usage of something they referred to as the "stress concentration factor" which sort of magically allowed them to magnify the erosive effects of cart wheels by a factor of ten. As a result they concluded that the passage of a single unladen cart while the limestone was wet would cause structural failure in the limestone significant enough to erode it noticably.
They figured a cart would weigh around 0.6 tons. Remove the "stress concentration factor" and suddenly you need carts pulling 6 ton loads before any erosion begins, which seems far more plausible to me...?

In any case, the entire cart argument strikes me as a kind of special pleading.