[meteorite-list] re: fossil meteorite impact channel?

From: Marco Langbroek <marco.langbroek_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:20 2004
Message-ID: <009201c3899b$51b357f0$f1c9ea3e_at_HAL>

Hi Elton,

> The 2-3 inch wide nugget was at
> the bottom of an apparent 10-8 inch long impact channel made while the
> very fine ooze was still mucky. The cavity had several "heart-valve"
> appearing "trap doors". They looked like partial refilling of the ooze
> after the meteorite had passed.

This sounds to me to describe a very common and normal geological phenomena
called "loading".

When a silty sediment is permiated with water, it becomes very soft. When
the tension at the surface is broken, objects from the surface (e.g.
pebbles) sink down untill it hits a sediment layer where the tension is
strong enough to stop it. The results is that you see, in cross-section, a
channel (that immediately is filled in again - and the layered patterning
resulting is quite what you decsribe) with an object at the bottom. It is a
very well known and understood geological phenomena, and I've observed it in
archaeological trench sections, both with natural objects and artifacts. In
some cases it need not even be a solid object, mudd-balls will do as well.

So I think there is no need to regard this as a fossil meteorite channel
unless the character of the object at the bottom of the channel was clearly
meteoritic.

- Marco

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Marco Langbroek

marco.langbroek_at_wanadoo.nl
meteorites_at_dmsweb.org
http://home.wanadoo.nl/marco.langbroek

"What seest thou else
 In the dark backward and abysm of time?"

                            William Shakespeare
                            The Tempest act I scene 2
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Received on Fri 03 Oct 2003 06:43:47 AM PDT