[meteorite-list] Re: Slickenside

From: Robert Verish <bolidechaser_at_meteoritecentral.com>
Date: Thu Apr 22 09:49:02 2004
Message-ID: <20010924045908.17122.qmail_at_web10407.mail.yahoo.com>

Hello Bernd, Charlie, and James:

Back in the 1999 List Archives you may find a thread
about "Slick-'n-side", but I haven't found it, yet.

As best as I can remember, we all agreed on the
definition for slickenside, but we came up with images
of so many varieties of this feature, that it just may
be possible that it may be produced by all 3 scenarios
that Charlie suggested:
a tectonic event on the parent body,
an impact event in space,
an explosive breakup in earth's atmosphere????

Since that 1999 thread, I have encountered many more
examples. More than several times, I had wished that
there were a web page for posting images of all these
varieties of slickenside (ala Martin's web site) in
order that it can be referred to, for just these kinds
of discussion purposes.

I have yet to find a definitive reference that can
answer Charlie's original question.

Bob V.

------------------ Reply Separator
[meteorite-list] Slickenside

James Baxter jbaxter112_at_pol.net
Sun, 23 Sep 2001 23:13:15 -0400 (EDT)

Hello Berndt,Charlie

As I recall from my past geology courses eons ago
slickensides are formed from the movement of rocks
relative to each other along fracture planes in fault
zones in terrestrial rocks.A kind of cool thing you
can do is rub your finger along the grooves which make
the slickensides.They feel rough when you move your
finger in the direction opposite to which the adjacent
rock moved to form the slickesides and smooth when you
rub in the same direction the adjacent rock moved
because it sheared off any microscopic projections or
rough edges as it moved.Again based on my feeble
memory of the distant past,that's one way to determine
movement direction along a fault in the field.

I have two pieces of Zag each of which show killer
slickensides so I assume this is a common feature of
Zag and must represent mechanical disruption at some
point in its history.

Best Wishes,
JIm Baxter

------------------ Reply Separator
Originally From: Bernd Pauli HD
Subject: [meteorite-list] Slickenside
Date: 09/23/2001 11:00pm

Charlie wrote:

> Can anyone clarify for me the origin of slickenside
in meteorites? I understand the term as it applies to
terrestrial soils and sediments. I have a large
individual of Plainview(1917). It's a flat specimen,
with one side fully crusted. The other side looks
more like a broken surface, with crust lipping over
the edge from the crusted side. This "broken" surface
is covered with glossy striations in large patches
I'm assuming is slickenside. What I would like to
know is if this slickenside formed during
a tectonic event on the parent body,
an impact event in space, or
an explosive breakup in earth's atmosphere,
or other?

Hello Charlie and List,

All I can contribute is a comment from our former,
competent list member Frank Stroik many years ago:

"slickensides are identified by shiny mirror like
surfaces on an otherwise rough rock - they are the
product of faulting in a rock body; as the crust
shifts, even slightly, the roughness of the rock
tends to smooth."
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Received on Mon 24 Sep 2001 12:59:08 AM PDT

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