Geology Reference
In-Depth Information
Figure 6.20.
Patterned ground. (A) Plug circles, Cornwallis Island, Arctic Canada. The photo
shows instrumentation used to measure vertical displacements at depth within a circle by free-
moving rods. Photo taken: August, 1988 (see Washburn, 1989, 1997). (B) Section through an earth
hummock showing cryoturbated organic material, Hume River region, near Fort Good Hope, NWT.
Photo was supplied by the late S. C. Zoltai. (C) The equilibrium model of earth-hummock forma-
tion, inferred by J. R. Mackay (1980b) following fi eld observations on Garry Island and at Inuvik,
western Canadian Arctic.
