302-Lecture 8

General Outline

Aeolian Processes and Landforms

I. Causes and location of deserts and grasslands

A. beneath subsiding STHs pressure centers

B. rainshadow

C. extreme continental position

II. Geomorphic processes

A. wind abrasion; pedestals, tors and ventifacts

B. water erosion; canyons, arroyos, intermittent wash

C. physical and chemical weathering

III. Aeolian processes

A. saltation and deflation

B. formation of desert pavement (reg) as lag deposit

C. deflation and loess deposits in U.S. and globally

IV. Dunes

A. dune morphology, growth and migration

B. dune types

C. effect of sand supply, vegetation cover, and wind strength

D. erg (sand sea) and star dunes

V. Erosion in arid regions

A. inselbergs, bornhardts and duricrusts

B. mesas, buttes and spires in sedimentary strata

C. typical landforms in mountain basins

D. playas, alluvial fans, pediments, bajadas

E. Basin and Range as example

VI. Denudation and landscape evolution in humid and arid regions

A. open vs. closed systems wrt mass

B. changes in mean elevation and relief over time, rejuvenation

C. peneplains and pediplains

D. examples

VII. Desertification

A. processes

B. geographic patterns in the U.S.

C. record from the Sahara