[meteorite-list] NWA 1836 (Twisted Sister) - Cataclastic?

From: Dawn & Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Thu Aug 4 14:29:16 2005
Message-ID: <047f01c59922$62ca4c90$6502a8c0_at_GerryLaptop>

Hi Jeff, could these catalysmic conditions be duplicated by collisional
events as opposed to tectonic?
My two cents. Jerry Flaherty
----- Original Message -----
From: "Jeff Kuyken" <info_at_meteorites.com.au>
To: "Meteorite List" <meteorite-list_at_meteoritecentral.com>
Sent: Thursday, August 04, 2005 2:35 AM
Subject: [meteorite-list] NWA 1836 (Twisted Sister) - Cataclastic?


> G'day,
>
> I have some questions about NWA 1836 I'm hoping someone may be able to
> answer or clarify.
>
> The classification description says that NWA 1836 is a "highly contorted
> mass of eucrite clasts with cataclastic mantles that are in turn covered
by
> partially melted to recrystallized masses."
>
> >From what I could find "cataclastic" refers to rocks that experience
sudden
> high-pressure and low-temperature conditions, resulting mainly in a change
> in texture of the original rock. My understanding is that this term is
> usually reserved for rocks found in places like those along tectonic fault
> lines.
>
> So are these conditions present in the parent-body? I would have thought
> that most high-pressure conditions would also be associated with
> high-temperature conditions. (i.e. impact) So is there in fact enough
> movement within the parent-body to cause a cataclastic effect and would it
> just be limited to some of the larger bodies?
>
> And the last part mentions "that are in turn covered by partially melted
to
> recrystallized masses." Does this mean there was later melting from a
> separate and/or different event?
>
> Sorry, there are a few questions here but I found it to be quite
> interesting. If it is indeed "cataclastic" in the traditional sense then I
> guess NWA 1836 could tell us a lot more about the kind of conditions
present
> on the parent-bodies, making this meteorite even more special.
>
> Thanks in advance,
>
> Jeff
>
>
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Received on Thu 04 Aug 2005 02:29:00 PM PDT