Mike - Impact melt glass at Meteor Crater is not pretty green or any
other pretty color, but dark "melt beads", dark glassy impactites, and
the reddish brown glass that is common in typical oxidized
impactites.The spherules are tiny.
Go to: D. A. Kring, “Guidebook to the Geology of the Barringer
(Meteorite) Crater, Arizona”. LPI Contribution No 1355 (2007) -
downloadable.
Has just about anything you want to know about Meteor Crater...
Ted
On 9/21/13 1:20 PM, Mike Fiedler wrote:
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
__
Visit the Archives at http://www.meteorite-list-archives.com
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
__
Visit the Archives at http://www.meteorite-list-archives.com
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list