[meteorite-list] Impact Glass from Barringer Crater?
From: Mike Fiedler <mlfiedler_at_meteoritecentral.com>
Date: Sat, 21 Sep 2013 13:20:31 -0700 Message-ID: <CANPcf8eSyCoM4Q4KZ5eu+oJ8EMggt4o=j665iqfTdOVo6=wkEA_at_mail.gmail.com> I finally got myself a copy of Nininger's Find a Falling Star. It is a great read, and insight into how doggedly he pursued his interests against a steady stream of naysayers among those who might have been inspired. My immediate interest, is the passage on page 180, in which he described a form of impact glass appearing in a variety of shapes, including 'tear-shaped'. Unlike the typical solid glass Indochinite, these seem to have encased a more non-homogenized interior, which Nininger describes as 'spongy'. (In a sense of pourous, not flexible or plastic) Here's a couple paragraphs from the book: {begin quote} Spurred on by discovery of the little metallic spheroids, I searched and searched everywhere on all sides of the crater, on the rim and on the plain beyond, examining everything more critically than ever before, and one day made an even more exciting find. I had stopped to examine a gravel pit dug into the crater rim by the state highway commission. I found a few crushed bits of yellow-green-brown slag; some showed a gray outer crust. I looked for more, and soon picked up a small tear-shaped piece. It appeared the same color as the light gray dust and gravel among which it lay, but the rockhound's licking test revealed a dark greenish-gray color under the dust. A canteenful of water dashed onto the gravel made it easier to identify a number of such small "bombs" of various shapes and sizes. All of these, when broken, were seen to be of a spongy structure, but composed of brittle, glassy material. When I ground the bits of slag on a sheet of carborundum cloth from my supplies in the trunk of my car, and then held them under a pocket lens, they showed small imbedded metallic particles, bright as chrome steel. As I drove hurriedly back to the museum on Highway 66 to make a nickel test, I puzzled over various questions. Could these be mere volcanic cinders? Could lava fragments carry such imbedded metallic particles? If these indeed were bomblets created by the impact of the meteorite, why had they never before been discovered? {end Quote} In looking for additional info, I came across this: http://www.impact-structures.com/2011/12/meteor-crater-arizona-discovery-of-impact-glass-spherules/ Not quite the same thing, but certainly intriguing! This would go well along side my Wabar Pearls and Chicxulub spherules from Dogie Creek, Wyoming. I have searched some of the Tektite web sites hoping to find a source for a specimen of the glass Nininger describes. I am coming up dry. Does Nininger's material exist on the market? What is it called? Any likelihood of tracking down those Barringer Crater spherules? Any clarification will be appreciated. Mike Received on Sat 21 Sep 2013 04:20:31 PM PDT |
StumbleUpon del.icio.us Yahoo MyWeb |