Desert Environments Flashcards
(15 cards)
What is the Hamada environment like?
Mountain areas with bare, rocky areas.
What is the Hamada environment formed by?
Weathering and erosion processes
What is the largest environment in the Sahara?
Hamada
What is the Reg environment like?
Gravel/pebble plain forming a transitional zone between the Hamada and the erg
What is desert pavement?
Hamada and Reg together
What is the Erg environment like?
Sand Dunes/Sand Seas
As a percentage, how many deserts in the world are sand dunes?
25%
In the Sahara, as a percentage, how much area is the erg?
28%
What is a positive feedback loop example for Desertification?
Desertification leads to decreased agricultural and livestock yields - local populations increase livestock numbers and extend and intensify cultivation
Deforestation and overgrazing occurs which causes soil quality to degrade and reduced vegetation leads to soil erosion by water and wind
How much as a % do hot deserts cover the land surface?
25-30%
What system is desert?
Natural Open systems
What are deserts usually in terms of equilibrium?
Dynamic equilibrium
Name an example of positive feedback in deserts
Wind flow may be changed by the growing dune until it can no longer carry sediment to top and deposit it. This means the dune will stop growing
Name an example of negative feedback in deserts
If temp increases, evaporation increases around bodies of water and the ground will be drier and can be easily eroded so dust clouds are more likely to form which blocks solar radiation so decreases temperature
When do desert pavements form?
When the wind blows away from the silt and sand from the desert surface leaving behind the gravel, rock etc that are too heavy to be removed by deflation
