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Eolian Landforms Wind An agent of erosion –“eolian” refers to wind 2 types of eolian erosion:...

Date post: 21-Dec-2015
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Eolian Landforms

Wind• An agent of erosion

– “eolian” refers to wind

• 2 types of eolian erosion:– abrasion: sandblasting

• YARDANG

– deflation: blowing away loose particles• DESERT PAVEMENT

Dust storms and sand storms

• Dust Storm:

– strong winds – sparsely vegetated – dust is carried high into air; dark cloud

Dust storms and sand storms

• Sand Storm:

– sand can be carried only 1-2 meters high – can be heard– sand moves by SALTATION

DUNE

• Accumulation of sand, shaped by wind

• Dunes have windward and leeward slopes

angle of repose

• Angle at which loose material is stable

• 30 – 34 ° for sand

Types of Sand Dunes:

1. Barchan

– point downwind– windward slope is gradual– leeward slope is steeper

Types of Sand Dunes:

2. Transverse:

waves of sand

crests are perpendicular to wind

Types of Dunes

3. Barchanoid

ridge of coalesced barchans

Types of Sand Dunes:

4. Parabolic:

point upwind

vegetation anchors arms

large blowout depression in center

Coastal Blowout Dune

– a type of parabolic– coastal location (Great Lakes)– point upwind

Hairpin

– type of parabolic– long and narrow– point upwind

5. Longitudinal

– parallel to wind direction

6. Star Dunes

– wind from all directions

Loess

• Silt-sized, wind-deposited deposit

• From outwash deposits of Pleistocene glaciers


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