Congratulations to Felix Bossert for being the quickest to solve the September puzzler. The answer is the Chara Sands. See the Image of the Day that published on September 21, 2013, for a second image and details about the area. Also congratulations to Robert Emberson for providing interesting details about the geologic history of the dunes.
It only took Bossert a few hours to get the answer—impressive because we hadn’t even promoted the puzzler through our email newsletter, Facebook page, or Twitter feed. I can’t say I’m surprised because Felix is a veteran of the geology puzzler Where on Google Earth (WOGE). Give WOGE a try, but make sure know the rules and be prepared to host the next WOGE if you win.)