Geoscience Reference
In-Depth Information
(a)
(b)
(c)
Figure 8.5
Examples of gypsum crusts. (a) An island of Archaean bedrock draped by gypcrete in the halite-encrusted floor of
Lake Lefroy, near Kambalda, Western Australia. The white outcrop in the foreground is uncemented very fine-grained gypsum
(locally called
kopi
), that has been deflated from the playa floor and recrystallised under the influence of percolating rainwater.
(b) Powdery pedogenic gypsum crust from the Tumas River in the Namib Desert, Namibia. This crust, unusually, is enriched in
uranium. (c) Desert rose crystals sampled from sabkha sediments between Terrace Bay and Agate Beach along the Skeleton Coast,
Namibia. Photograph (a) courtesy of Allan Chivas; photographs (b) and (c) courtesy of Frank Eckardt.
