Geoscience Reference
In-Depth Information
aeolian salt, silt +
clay input
tight,
interlocking
clasts
clast size diminishes
Av
columnar peds
C Horizon
direction of sediment
movement
0
~ 4,000 to 10,000 years
TIME
Figure 9.8
A simplified conceptual diagram of soil pavement formation according to the aeolian aggradation model. Over time,
the surface rises owing to the input of fine aeolian sediment. A thin monolayer of clasts is preserved at the surface, with the
rocks becoming smaller and more tightly interlocked over time as they weather. A vesicular (Av) horizon forms under the clasts.
As aerosolic fines accumulate, distinct columnar shapes develop. The aeolian fines and solutes may be transported downwards
through the polygonal cracks and the dust moved horizontally along platy boundaries to ped interiors. The establishment of a
mature desert pavement may take 4000-10 000 years or longer. After Anderson, Wells and Graham, 2002, and Young
et al.
, 2004.
Figure 9.9
A heavily varnished pavement (similar to that shown in Figure 9.4) located in the east-central Mojave Desert,
California, near the Cowhole Mountains. The gravel sits above 30
+
cm of silty material that is largely free of stones.
