Environmental Engineering Reference
In-Depth Information
Plate 16.1 Arid landforms in the Mojave desert, southern
California, USA, contributing debris to the aeolian system.
Gravels fans forming the bajada give way to finer sands and
silts as debris is swept towards the adjacent playa, from
where it is deflated to form sand seas and dunes.
Photo: Ken Addison.
DESERT LANDSYSTEMS
DESERT PAVEMENTS, LAGS AND VENTIFACTS
Deflation initially produces remnant landforms in areas stripped of sand and silt. Non-
deflatable, coarse-grained lag gravels loosely protect underlying abraded bedrock
surfaces or hamada to form desert pavement . Residues from the restricted chemical
weathering in deserts is rapidly deflated. Lag clasts themselves are abraded in situ as
deflation continues and, if large enough to remained static, sandblasted facets develop on
the windward side of these ventifacts , often giving a three-faced or dreikanter
appearance. Desert pavements, known also by their alternative Arabic or aboriginal
names reg and gibber , eventually become sterile unless further fines are introduced to
stimulate abrasion.
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