1. DESERTS AND WIND ACTION

2. DESERTS AND WIND ACTION
Desert regions and wind erosion
Desert and adjacent region
desert
region which has an arid climate
steppe
region adjacent to a desert with semiarid climate

3. DESERTS AND WIND ACTION
Desert (arid climate) and
steppe (semiarid climate) areas on Earth

4. DESERTS AND WIND ACTION
Wind erosion processes
deflation is the removal of rock waste from the land by the wind
blowout or deflation hollow is a depression excavated by the wind in materials as sand and silt deposits easily eroded because of a lack of the presence of adequate vegetation which impedes deflation

5. DESERTS AND WIND ACTION
Blowout or deflation hollow

6. DESERTS AND WIND ACTION
Deflation Hollow---Blowout

7. DESERTS AND WIND ACTION
abrasion is the “sandblasting”effect on materials caused by the impact with particles carried by the wind—frosted windows in houses and ventifacts form

8. DESERTS AND WIND ACTION
Wind erosion loads
suspended load
suspended wind blown particles
consists primarily of silt or clay size particles and if highly concentrated can result in dust storms
deposition of the suspended load can result in large deposits of loess lacking layering or stratification

9. DESERTS AND WIND ACTION
Dust Storms

10. DESERTS AND WIND ACTION
Loess Deposits

11. DESERTS AND WIND ACTION
bed load
particles bounced along the ground
usually consists of sand size particles
accumulation of the bed load forms desert sand dunes which can migrate easily(active dunes)
Active sand dunes
Nature of active (unstable) dunes
dune profile
consists of a more gentle windward slope and steeper leeward slope or slipface

12. DESERTS AND WIND ACTION
Dune profile

13. DESERTS AND WIND ACTION
shifting dunes
shift downwind and can bury roads, airport runways, homes, etc.
Categories of active dunes
based on shape of dune in plan view
barchan
crescent shaped with convex portion facing the wind direction
formed with a constant wind direction and limited sand supply

14. DESERTS AND WIND ACTION
Barchan dunes

15. DESERTS AND WIND ACTION
transverse
elongated perpendicular to direction of wind
formed with a constant direction of wind and large supply of sand

16. DESERTS AND WIND ACTION
longitudinal or seif
elongated in general direction of wind
formed with slightly different wind directions and limited sand supply

17. DESERTS AND WIND ACTION
star or complex
formed with variable wind direction

18. DESERTS AND WIND ACTION
Desert landscape and evolution
Alluvial fan
fan shaped deposit formed at the foot of mountains in the desert valley or basin

19. DESERTS AND WIND ACTION
a bajada is an apron of sediment resulting from a coalescence of alluvial fans

20. DESERTS AND WIND ACTION
Playa lake and playa
a temporary shallow lake formed in the central basin of a desert during a rare abundant rainfall--a playa is the dry flat lake bed that remains

21. DESERTS AND WIND ACTION
Inselberg
an isolated erosional remnant present after long term erosion of mountain areas which are reduced to these bedrock knobs elevated above the surrounding sediment filled basin

22. DESERTS AND WIND ACTION
Pediment
a carved gently sloping erosional surface on the bedrock in a desert mountainous area

23. DESERTS AND WIND ACTION
Stages of landscape in mountainous desert regions

24. DESERTS AND WIND ACTION
Inactive or stable dune---mostly non-desert
Parabolic dune(foredune)
formed along coastlines of oceans or large lakes
winds cause blowouts in sand resulting in a crescent shape with the concave side facing the prevailing wind direction

25. CYBER GEOLOGY COURSE FOLKS
THAT’S ALL THE
CYBER GEOLOGY COURSE FOLKS