[meteorite-list] ringwoodite?

From: E.L. Jones <jonee_at_meteoritecentral.com>
Date: Thu Apr 22 10:29:52 2004
Message-ID: <3F5BB89D.2080900_at_epix.net>

Tom aka James Knudson wrote:

>Hello List, in a terrestrial rock, Is there anything that resembles
>ringwoodite/shock veins?
>Thanks, Tom
>
Shock Veins-- yes. I suppose slickensides could resemble a shock
fracture which is filled in by any of several minerals. Contraction
cracks in mudstone can be filled with silica gel only it is called
boulder opal. Real Fracture veins are found in earthquake rupture zones

Ringwoodite on earth is believed to be very plentyfull just not on the
surface. It is theorized to exist starting in a zone 50-80 kilometers
below your foot. (Be it remembered that ringwoodite is the spinel habit
/ high pressure form of olivine (Mg,Fe SiOx))

Superficially, I suppose there are a number of things which might
resemble ringwoodite. Fluorite comes to mind but a hardness test should
distinguish them. I don't remember seeing anything terrestrially that
closely resembles a true shock fracture infilled with a melt material.

Could you give a little more detail? Are you trying to identify
something specifically or are you just asking so you could be prepared
when you do find it?

Elton
Received on Sun 07 Sep 2003 07:00:45 PM PDT