Chapter 18- The Topography of Arid Lands

Question 1

What makes the desert a specialized environment?

Answer 1

Sand, impermeable surfaces, wind action, most streams are ephemeral (flow only following a
rainfall)
- Yet, alluvium is very common in deserts, and so are basins of internal drainage.
- Running water is actually the single most important agent of erosion in deserts.
- Surface water in the desert: exotic streams (e.g., Nile River, Colorado River),
ephemeral streams, playas, and saline lakes.

Question 2

Aeolian erosion:

Answer 2

deflation (blowout of loose material) and abrasion (pitting by flying sand
grains)

Question 3

• Aeolian transportation:

Answer 3

suspension, saltation, traction (similar to streams, but no salts in
solution)

Question 4

Characteristic desert landscape surfaces: Erg—a sea of sand; Reg—stony deserts.
What is desert varnish?

Answer 4

An inselberg is an isolated hill rising abruptly from a plain

Question 5

Why are they best seen in deserts?

Question 6

Two types of common desert landforms in the U.S. Southwest:
Basin-and-Range

Answer 6

Basins (valleys) and ranges (mtns) created by ongoing tension pulling in an east-west
direction.
Also, piedmont bajadas are where alluvial fans merge. Badlands are heavily eroded terrain.
Excellent examples in Death Valley, California and the Basin & Range province, Nevada

Question 7

Mesa-and-scarp

Answer 7

Mesa—Spanish for “table,” flat topped surface; Scarp—short for “escarpment,” pertains to
steep cliffs.
Excellent examples in Arizona and New Mexico