Desert surfaces: pavements, patterned ground, varnishes and crusts
267
(a)
NONORTHOGONAL
(b)
(c)
(d)
REGULAR RANDOM
IRREGULAR RANDOM ORIRNTED ORTHOGONAL
ORTHOGONAL
ORTHOGONAL
Figure 12.9. Common systems of desiccation cracks (after Lachenbruch, 1962, and Neal, 1965, in Cooke
and Warren, 1973, Figure 2.25).
CERBAT
MOUNTAINS
0
1.5
km
.,o., .... ,....,.
,,"'('no
"'""
coverage ",..
,'
available)
"'.
i I
p
9
i
s -p"
\
,. ..... .
,s
,,
,.,"
%
',,
1
' ,,
|0
",,.
I, site I ,/,,,J/
'4 ~(
/ ~ fresh ~"
t ~ -,~1
f l,~,k
~)
fissures ~'~'~ ~ ~..
_'~.,"
,
l z
,~'~ ...... "'-~-,4;,~.~"5"," ~
"
I=_
"
iF
/ ~
fresh
" "~
\
~
"X ~
fissures ~
//
.
._,~',,o -'~
.
Figure 12.10. A generalised map of giant desiccation polygons, earth fissures and areas of recent
fissuring, Red Lake Arizona, based on the interpretation of aerial photographs. The fissures are attributed
to long-term desiccation and local subsidence due to water extraction and/or subsurface salt flow (after
Lister and Secrest, 1985, in Cooke et al., 1993, Figure 8.6).