Deflation hollow
Also called: Blowout · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 9, Ch 2 "Shaping of the Earth's Surface"; Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A deflation hollow, also called a blowout, is a shallow dip in the ground. It is scooped out where wind keeps blowing from one direction. The wind removes weathered (broken-down) material or bare soil. Blowouts can grow deeper, and some even turn into caves. If a hollow is cut down to the level of groundwater, water seeps in. Plants can then grow there and an oasis can form.
Example
The Qattara Depression in the Western Desert of Egypt is a huge basin that wind helped scoop out. Its floor lies below sea level and holds salt marshes.
Don't confuse with
- Sinkhole: this is a funnel-shaped pit in limestone. Rock dissolving in water makes it, not wind.
- Playa: this is a flat desert basin with a shallow lake that comes after rain. It forms by inland drainage, not by wind blowing material away.
Related concepts
- Aeolian processes
- Deflation
- Wind abrasion
- Sheet flood
- Erg, reg and hamada
- Pediment
- Parallel retreat of slopes
- Pediplain
- Inselberg
- Playa