Geology 4th edition by Chernicoff & Whitney Chapter 18 Deserts and the Work of Winds Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. What Is a Desert? A region that receives very little annual rainfall and is generally sparsely vegetated A region where the aridity index (ratio of potential evaporation to annual precipitation) is greater than 4.0 Figure 18-2 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Deserts of the World Figure 18-4 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Types of Deserts Subtropical Rain-shadow (orographic) Continental interior Cold-ocean current Polar Figure 18-3 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Types of Deserts Subtropical Rain-shadow (orographic) Continental interior Cold-ocean current Polar Figure 18-5 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Types of Deserts Subtropical Rain-shadow (orographic) Continental interior Cold-ocean current Polar Figure 18-4 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Types of Deserts Subtropical Rain-shadow (orographic) Continental interior Cold-ocean current Polar Figure 18-6 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Types of Deserts Subtropical Rain-shadow (orographic) Continental interior Cold-ocean current Polar Figure 17-25 Copyright © 2007 Pearson Prentice Hall, Inc.
Weathering in Deserts Primarily mechanical weathering Desert varnish Figure 5-8 Figure 18-8 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Desert Processes Stream erosion Stream deposition Wind erosion Wind deposition Figure 18-10 Figure 18-1 Copyright © 2007 Pearson Prentice Hall, Inc.
Stream Erosion in Deserts Arroyos & canyons Pediments Inselbergs Figure 18-9 Copyright © 2007 Pearson Prentice Hall, Inc.
Stream Erosion in Deserts Inselberg formation Figure 18-11 Copyright © 2007 Pearson Prentice Hall, Inc.
Stream Deposition in Deserts Alluvial fans Playa Figure 18-9 Copyright © 2007 Pearson Prentice Hall, Inc.
Stream Deposition in Deserts Playa deposition Figure 18-12 Copyright © 2007 Pearson Prentice Hall, Inc.
The Work of Winds How winds work Figure 18-14 Copyright © 2007 Pearson Prentice Hall, Inc.
The Work of Winds How winds work Figure 18-15 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Erosion in Deserts Deflation Blowouts Deflation basins Abrasion Figure 18-16 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Erosion in Deserts Deflation Abrasion Balanced rocks Ventifacts Yardangs Figure 18-17 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Erosion in Deserts Deflation Abrasion Balanced rocks Ventifacts Yardangs Figure 18-18 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Erosion in Deserts Deflation Abrasion Balanced rocks Ventifacts Yardangs Figure 18-19 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Transport in Deserts Bed load Rolling Saltation Suspended load Figure 18-20 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Transport in Deserts Highlight 18-2 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Deposition in Deserts Bed-load deposition - Sand dunes Figure 18-23 Copyright © 2007 Pearson Prentice Hall, Inc.
Sand Dunes Dune formation Figure 18-22 Copyright © 2007 Pearson Prentice Hall, Inc.
Sand Dunes Dune migration Figure 18-25 Copyright © 2007 Pearson Prentice Hall, Inc.
Sand Dunes Dune migration Figure 18-26 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Sand Dunes Dune shapes Transverse dunes Longitudinal dunes Barchan dunes Parabolic dunes Star dunes Figure 18-28 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Sand Dunes Dune shapes Transverse dunes Longitudinal dunes Barchan dunes Parabolic dunes Star dunes Figure 18-28 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Sand Dunes Dune shapes Transverse dunes Longitudinal dunes Barchan dunes Parabolic dunes Star dunes Figure 18-28 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Sand Dunes Dune shapes Transverse dunes Longitudinal dunes Barchan dunes Parabolic dunes Star dunes Figure 18-28 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Sand Dunes Dune shapes Transverse dunes Longitudinal dunes Barchan dunes Parabolic dunes Star dunes Figure 18-28 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Deposition in Deserts Suspended-load deposition - Loess Figure 18-29 and 18-30 Copyright © 2007 Pearson Prentice Hall, Inc.
Wind Deposition in Deserts Suspended-load deposition - Desert pavement Figure 18-32 Copyright © 2007 Pearson Prentice Hall, Inc.
Reconstructing Paleowind Direction Figure 18-33 Copyright © 2007 Pearson Prentice Hall, Inc.
Copyright © 2007 Pearson Prentice Hall, Inc. Desertification The invasion of desert conditions into formerly non-desert areas Figure 18-34 Copyright © 2007 Pearson Prentice Hall, Inc.
Desertification Natural processes Figure 18-36 Copyright © 2007 Pearson Prentice Hall, Inc.
Desertification Human induced Figure 18-37 Copyright © 2007 Pearson Prentice Hall, Inc.
Desertification Reversing desertification Figure 18-38 Copyright © 2007 Pearson Prentice Hall, Inc.
Extraterrestrial Wind Action Wind features on Mars Figures 18-39 and 18-40 Copyright © 2007 Pearson Prentice Hall, Inc.