[meteorite-list] Slickenside

From: Starbits_at_aol.com <Starbits_at_meteoritecentral.com>
Date: Thu Apr 22 09:49:02 2004
Message-ID: <129.5138c11.28e180fd_at_aol.com>

<Charlie wrote: What I would like to know is if this slickenside formed
during a tectonic event on the parent body, an impact event in space,
explosive breakup in earth's atmosphere, or other?>

Slickensides are formed by tectonic events. They are formed when opposite
sides of rock faults move in different directions. The extreme pressure
generates frictional heat as the rock faces are forced past each other
partially melting a thin veneer of rock at the interface. This results in a
smoothing of rough edges and a polished looking surface. Harder protrusions
gouge grooves in the opposite rock as it slides by.

They would not be formed by explosive breakup in the earth's atmosphere. In
such a breakup pieces would be flying apart from each other whereas in
slickensides the opposite is happening the rock faces are being forced
against each other.

They could possibly be formed by an impact event in space, not by the
explosive part of the impact, but by tectonic reactions along faults during
or after the impact.

<Bernd wrote: ... and some meteorites that are reported to exhibit

I have a piece of Mocs which shows good slickensides. There is a photo at
the following URL. It is not a great photo, but you can see the grooves and
that some parts are more reflective (polished) than others. Another
meteorite that exhibits slickensides is Gobabeb.


Eric Olson
Received on Tue 25 Sep 2001 02:41:01 AM PDT

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