Question

difference between loess and sand dunes

Answer 1

loess is a soil and sand dunes are storms in deserts

Answer 2

a dune is a hill of sand built by aeolian processes( ie wind) which can travell pretty quickly, Loess is an aeolian sediment which forms by the accumulation of wind-blown silt and lesser and variable amounts of either sand or clay (which covers an area over a lot amount of time).

Loess is a homogeneous, typically nonstratified, porous, friable, slightly coherent, often calcareous, fine-grained, silty, pale yellow or buff, windblown (aeolian) sediment.