Any geologists around? (non e/e question)

Aeolian processes.

Usually I've conceptualized large aeolian formations as being somewhat catastrophic in nature, like a giant dune field engulfing the landscape, then stabilizing and becoming covered in vegetation after many years.

But about a month ago it occurred to me that maybe it's a more gradual process, where the hills in question may be vegetated and appear to be stable, but in reality they're moving, albeit very slowly.

Which is a better conceptualization of these processes? :shrug:

Thanks, and sorry for the off-topic post.

Aeolian processes just mean wind driven geologic processes. On a broad scale this is a fairly simple idea though the specifics can get quite complicated and I actually have one friend from grad school who made it is specialty. At it's most basic level we're talking about how wind drives erosion, transport, and deposition of geologic materials as well as the geomorphology of the land forms this creates.

The erosion phase is most commonly strong winds blowing sand and other small particles into rock faces causing a sandblasting effect which erodes and shapes these features. Transport is how the wind carries these small particles; do they form dunes or are the particles small enough where they are blown up in the air and transported much longer distances? Lastly we have deposition which maybe a permanent deposition of sediments or we might just be talking about a temporary deposition where sediments might last 1 year, 10 year, 500 years before they get picked up and moved again.

You asked about sand dunes and the first thing you need to understand is that climate is the major controlling factor since it controls both the wind and the amount of water found in the environment. Most often dunes blow back and forth across a plain because the direction of the prevailing winds changes with the seasons. Most of the time in the winter the wind blows off of oceans and on to land while in the summer time the inland areas get warmer more quickly then coastal area so the wind blows from the land to the sea. Now if the sand reaches an area where there is enough rain fall then plants will grow and rain water will help compact the sand and this will stabilize the dune preventing it from continuing to move. If those plants should die or if the erosional process succeeds in over coming the stabilizing processes then of course these dunes could start moving again. This is actually what we've seen on the edges of the Gobi desert where there are lots of stabilized dunes covered with grass but due to drought or human activity the plants die and the dunes start moving again essentially resulting in redesertification.