Rodger, Glad you enjoyed it.  The closing step in determining Upheaval's origin as a meteor impact would be independent confirmation of Kenkmann's PDF quartz crystals in the outer ring.  If you are ever up to go down and take a small core sample (with NPS permission of course),  I'm happy to lug your gear for the 2 kilometers to get to Kenkmann's sample site. -:)    Merry Christmas. - Kurt