Geology Reference
In-Depth Information
(A)
Figure 6.19.
Stone tilting. (A) Uptilted siltstone and sandstone slabs of Weatherall Formation
(late Devonian age), near Rea Point, Eastern Melville Island, Arctic, Canada. (B) Illustration of
the mechanism by which a stone becomes tilted through repeated freezing and frost heaving of the
ground, according to Pissart (1970).
the middle layer, a single domed structure developed at the surface by extrusion of fi ner
particles from below, to form a simple circle. A number of other experiments emphasize
the importance of negative frost-susceptibility gradients in producing the upward injection
of fi ner materials to the surface to form mudboils or coalescing sorted circles (van Vliet-
Lanoë, 1988, 1991).
