How is a pediment different from an alluvial fan? ...

[nramada]

How is a pediment different from an alluvial fan?

Question 2

Name a type of sand dune that could form in each of these conditions: an area with abundant sand supply and winds that blow from a constant direction, an area with bidirectional winds blowing from neighboring quadrants (such as northwesterly and southwesterly), and an area with winds that blow from varying directions.

[gasdhashg]

Answer to Question 1

Pediments are broad, gently sloping surfaces of eroded bedrock leading up to a steep bedrock face. They are left behind as the bedrock face retreats. Alluvial fans are steeper deposits localized at the mouth of canyons in mountainsides. Some alluvial fans contain debris flow deposits, but most are made of strongly sorted clasts. In either case, material moves downslope and out from the canyon.

Answer to Question 2

Transverse dunes form where abundant sand is blown by constant winds. Bidirectional winds can produce longitudinal dunes. If the wind direction is extremely variable, star dunes can form.