[meteorite-list] Bull's-eye chondrule assumptions

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Mon Mar 21 13:24:57 2005
Message-ID: <00b601c52a83$65bb4020$6401a8c0_at_Dell>

Bernd and List,
Wonderful news about the possible accretionary process (even in this limited
occurence) in chondrule formation. In an earlier thread iniated by me, I had
asked if the "accretionary lapille" process could be "at all" analagous to
chrondrule origins. Even a limited (i.e.bullseye) possiblity, and I repeat,
possible accretionary chondrule origin in the primordial solar nebula is to
me, intrigueing.
Jerry
----- Original Message -----
From: <bernd.pauli_at_paulinet.de>
To: <Meteorite-list_at_meteoritecentral.com>
Sent: Wednesday, March 16, 2005 4:48 PM
Subject: [meteorite-list] Bull's-eye chondrule assumptions


> John and Dawn wrote:
>
>> We seem to have several of them in our new LL3
>
> Christian responded and presented some stunning pictures:
>
>> I have many of them: ...
>
> Whereupon John and Dawn wrote:
>
>> I really liked NWA 1770
>
> I am in love with the perfect bull's eye in Christian's NWA 724!
>
>> www.austromet.com/collection/NWA_0724_5.646g.jpg
>
> Do I have any ideas on the formation of such chondrules?
>
> Only some ideas, no references, no direct links: These chondrules
> obviously occur only in unequilibrated chondrites of types H3.x,
> L3.x, and LL3.x (by inference probably also in some E3 chondrites),
> up to petrologic type 4.
>
> Darker core material seems to be enveloped by a lighter-colored, in
> some cases almost concentric ring of (fine-grained, dusty?) material.
>
> The process that gave birth to such chondrules may have been either
> accretionary or condensational and the environment may have been
> dusty (which would point to early solar system processes).
>
> Obviously only a limited number of chondrules underwent this process
> so that the bull's-eye chondrule formation may have been a selective
> process (time, distance from the protosun, dusty environment..I don't
> know).
>
> It would be interesting and helpful if someone detected such bull's-eye
> chondrules in one of their thin sections so that we could draw further
> conclusions on their mineralic compositions (core material, rim or seam
> (?) material, high-temperature, low-temperature phases, etc.).
>
> Esteemed list member Jeff Grossman wrote several papers on chondrule
> formation, chondrule composition, zoned chondrules, etc. Maybe he can
> enlighten us on these "Eyes of Taurus", the Bull, my Constellation :-)
>
> Best wishes,
>
> Bernd
>
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Received on Wed 16 Mar 2005 06:53:47 PM PST