[meteorite-list] Shatter Cones, photos + double shatter cone

From: Jarmo Moilanen <impactite_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:24 2004
Message-ID: <1077264713362.impactite.1897.U35A9dBxw9hjmDgh2xIKrQ_at_luukku.com>

Hi list,

Nice shatter cones Mark...

Here is some photos of shatter cone boulders at Keurusselk=E4 impact struct=
ure found last November. Unfortunately, they are not in my collection, sinc=
e they are too big boulders:

http://www.somerikko.net/impacts/keurusselka.html=20

see also our Keurusselk=E4 LPSC-abstract (made in hurry): http://www.lpi.us=
ra.edu/meetings/lpsc2004/pdf/1619.pdf=20

Shatter cone photos can be seen also in my collection pages (click impactit=
es):
http://www.somerikko.net/old/geo/col/col.htm=20

As for hint where to look at: I have shatter cones from: Beaverhead, Charle=
voix, Dellen, Flynn Creek (weak), Gardnos, Glover Bluff, Kara, Karikkoselk=
=E4, Kentland, Keurusselk=E4 (no photos yet), Lappaj=E4rvi, Marquez Dome, M=
iddlesboro (weak), Paasselk=E4, Ries, Rochechouart, Rubielos de la C=E9rida=
, Saarij=E4rvi, Serpent Mound, Siljan, Steinheim, Sudbury, Suvasvesi struct=
ures, Suvasvesi S, S=E4=E4ksj=E4rvi, Vredefort and Wells Creek.

Jarmo Moilanen
www.somerikko.net
impactite_at_luukku.com

MARK BOSTICK kirjoitti 20.02.2004 kello 03:57:
> Hello List,
> Shatter cones are one of my favorite types of meteorite impactite. Found
> around large impact craters, called astroblemes (from Greek astron,
> blema,
> meaning "star wound"). Shatter cones have a distinctively patterned
> structure that are formed in the rock by a large impacting object. Often
> conically-shaped, these rocks have close-spaced "grooves" or "lines"
> that
> radiate outward from the apex. The apex, or point, of the stone points
> towards the impact area. I've always thought of shatter cones as a sound
> fossil. An Earth rock that has recorded the sound wave of the a large
> object from outer space announcing its arrival to earth.
> The following are photos showing most of the shatter cones in my
> personal
> collection. A couple I wanted to show were cut and you could see a
> cross of
> shatter cones in layers. Usually, you can break a shatter cone, and
> create
> two shatter cones. Some times something pretty, some times not. The
> three
> bottom photos show a shatter cone many of you might find of
> interest. This
> was found by Robert Szep, who told me he found it along the S.W.
> portion of
> Wanapitei Lake, about 30 yards from the shoreline. This was sold to
> me as a
> "double shatter cone", something that I have seen reported in several
> books. According to Szep both ends, or apex were pointed in the correct
> fashion for it to be a double shatter cone (each towards one of the
> craters). However, I understand that sometimes, the sound-shock wave
> from
> the Sudbury impact, appeared to bounce in the target rock, leaving a
> crinkle. The examples I have seen have been only in photos and are very
> large, not on a small scale such as this specimen. The shatter cone
> breaks
> at almost a 90 degree angle. =20
> Any impact cratering, physics or sound expert out there have any
> opinion on
> this rock? I have always felt sorry for the stone, hit by two
> meteorites.
>=20
> Beaverhead Shatter cone. (Not large for the local, but for most
> collections
> it is). Almost perfect cone shape.
> http://www.meteoritearticles.com/files/Beaverhead_Shattercone.jpg
> http://www.meteoritearticles.com/files/Beaverhead_Shattercone_on_side.jpg
>=20
> Kentland Shatter cone
> http://www.meteoritearticles.com/files/Kentland_Shattercone.jpg
>=20
> Rochochouart Shatter cone
> http://www.meteoritearticles.com/files/Shattercone_Roch.jpg
>=20
> Sheinheim Shatter Cone. The second one is "cute".
> http://www.meteoritearticles.com/files/Steinheim_Shattercone.jpg
> http://www.meteoritearticles.com/files/Steinheim_Shattercone_nice.jpg
>=20
> Wells Creek Shatter Cones
> First photo is positive side, second is negative side
> http://www.meteoritearticles.com/files/Shattercone_Wellcreek_1.jpg
> http://www.meteoritearticles.com/files/Shattercone_Wellcreek_b.jpg
> Shattercone with nice "horsetailing", second photo is closeup
> http://www.meteoritearticles.com/files/wells_Creek_Shattercone.jpg
> http://www.meteoritearticles.com/files/Wells_Creek_Shattercone_foxtailing=
jpg
>=20
>=20
> Serpent Mound Shatter Cones
> http://www.meteoritearticles.com/files/Sijin_Shattercone.jpg
>=20
> Siljan Shatter cone
> http://www.meteoritearticles.com/files/Serphant_Monnd_Shattercone.jpg
>=20
> Sudbury Shatter cones
> 3.5 kilogram Sudbury Shatter cone.
> http://www.meteoritearticles.com/files/Sudbury_Shattercone_3.5kg_side.jpg
> http://www.meteoritearticles.com/files/Sudbury_Shattercone_3.5kg.jpg
>=20
> Large flat Sudbury Shatter cone.
> http://www.meteoritearticles.com/files/Sudbury_flat_shattercone_side_1.jp=
g
> http://www.meteoritearticles.com/files/Sudbury_flat_shattercone_side2.jpg
>=20
> A Sudbury and Winnipeg double shatter cone. =20
> http://www.meteoritearticles.com/files/Sudbury_Winnipeg_Shattercone.jpg
> http://www.meteoritearticles.com/files/Sudbury_Winnipeg_Shattercone_Side_=
1.j
> pg
> http://www.meteoritearticles.com/files/Sudbury_Winnipeg_Shattercone_Side_=
1.j
> pg
>=20
>=20
>=20
> Please visit, www.MeteoriteArticles.com, a free on-line archive of
> meteor
> and meteorite articles.


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Received on Fri 20 Feb 2004 03:11:53 AM PST