Jon,
re. reply #28:
"Silt sized particles do not make dunes. If they are aggregated to form sand sized particles then they can. But then they are no longer silt from a sedimentological perspective."
I have to disagree, this is the geology page after all.
Silt does not have to be aggregated to sand sized particles in order to be form/be incorporated into dune-like structures by the wind. There are examples of this all over the world. Here are a few of many links with information and photographs of dunes composed primarily of silt-sized particles. Admit it, they do exist.
[link]
[link]
http://www.bsyse.wsu.edu/saxton/cp3/Papers/Poster/Poster.htm
http://www.carnegiemuseums.org/cmnh/ip/tours/trail/red/5.htm
[link]
[link]
http://geosun.sjsu.edu/paula/134/pdf/lecture20b.pdf
Best regards,
Robert
