Dunes on the surface of a planet indicates it has loose sand being blown by wind.
winds
Mars
I'd have to go with "wind."
It was open hard desert with sand dunes to the south.
Seif dunes and star dunes in Algeria
Wind erosion causes all the conditions mentioned in your question.
Large piles of sand are called dunes.
There are only two sand dunes in Michigan. The two sand dunes are Sleeping Bear Dunes and Sliver lake sand dunes.
Fore dunes and back dunes but mostly fore dunes.
Silver Lake Sand Dunes and Sleeping Bear Dunes
sand dunes are caused by deposition . some people think its caused by erosion , but erosion is the braking down of land formations. sand dunes are caused by strong winds pushing sand grains into piles.
sand dunes change