Kim, Interestingly enough I moused over the words “shock quartz” in your post and a link to Wikipedia came up which relates the following with mention of Eugene Shoemaker: Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz will be deformed along planes inside the crystal. These planes, which show up as lines under a microscope, are called planar deformation features (PDFs), or shock lamellae. Shocked quartz was discovered after underground nuclear bomb testing, which caused the intense pressures required to form shocked quartz. Eugene Shoemaker showed that shocked quartz is also found inside craters created by meteor impact, such as the Barringer Crater.[1] The presence of shocked quartz proves that these craters were formed by an impact: a volcano would not generate the pressure required. Jim --- On Wed, 1/28/09, Kim <kimharch@cut.net> wrote: From: Kim <kimharch@cut.net> Subject: Re: [Utah-astronomy] More on Upheaval Dome To: "'Utah Astronomy'" <utah-astronomy@mailman.xmission.com> Date: Wednesday, January 28, 2009, 10:15 AM I've missed some of this thread, and my memory may be faulty, but I thought that microscopic shocked quartz was first documented at Upheaval Dome by Gene Shoemaker, perhaps 20 years or so ago. I don't recall now where I learned that. Anyone else? Kim -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of zaurak@digis.net Sent: Wednesday, January 28, 2009 10:05 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] More on Upheaval Dome Canyonlands certainly has no shortage of unique features not seen anywhere else. No virus found in this outgoing message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.15/1921 - Release Date: 1/28/2009 6:37 AM _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com