Greetings ! I'm not certain the above name of the proccess is correct. What I'm talking about is the phenomenon that's occuring since the end of the last ice age - more and more areas are turning into deserts. I also believe that the opposite also happened many times (though I'm not certain). My question is - how does it happen ? What are the materials involved specificly ? How can normal earth turn into sand and back ? (Links will also be appreciated.) Thanks ! Live long and prosper.