Deflation hollows = is where wind has removed sand down to a level where a layer of particles too heavy for the wind to move (an armoured surface) stabilises the sand and prevents the surface being lowered further
Crevasses=it’s mean a deep open crack like for example on the glacier
Morain= an accumulation of earth and stones carried and finally deposited by a glacier.
Defletion hollows: Defletion hollows are ever wind has removed sand down to a level where a layer of particles is too heavy for the wind to move stabilises the sand and prevent the surface being lowered further. It's also known as blow out dune.
Explanation:
Sorry ,I only know about this so i can't tell u of others
