Arabian Desert rock formation
There are two water-related erosional process at work here:

The exhumation of main sandstone blocks caused by heavy rainfall, incising channels and carrying away the loose debris for deposition elsewhere as &quot;sand&quot;.

Formation of weather resistant surfaces caused by dissolution and re-precipation of iron-rich minerals.


You often see this process at work in any desert environment bearing iron-rich sandstones. The morphology, however, will differ based on the internal structure of the rock. Where high winds can carry sand, these iron-rich surfaces can become highly polished into a varnish-like surface.