[meteorite-list] chondrules?

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Mon Feb 14 20:53:36 2005
Message-ID: <029b01c51301$2699b5f0$6401a8c0_at_Dell>

Subject: Re: [meteorite-list] a question about chondrules
I'm reposting this as I received only one response. Please reply if you
have any thoughts on this question. Thanks a lot in advance3.

> ON THE ORIGIN OF CHONDRULES
> Norm and List,
> Please excuse my ignorance for putting forth this question but as a
> relative "newbe" to meteorite collecting, I hope you will entitle me to
> this query.
> I came across the term "accretionary lapilli" also called "volcanic
> pisolites" in Dorothy Ferris Lapidus 1987 edition of "The Facts on File
> Dictionary of Geology and Geophysics.
> If you bear with me I'll quote " these are shperoidal concentrically
> layered pellets composed mainly of vitric dust and ash, usually between 2
> and 10 mm in diameter. They are formed primarily through the accretion of
> ash and dust by condensed moisture in eruption clouds. Formless nuclei of
> coarse particles fall through the fine debris and acquire shells of
> progressively finer ash. These concentric shells indicate the increasiing
> temperature and decreasing humidity of the cloud at lower levels.
> My question is, does the process described above provide any
> anology("something similar but different") to the origin of chondrules.
> A solar nebula is obviously different than a volcano but is there any
> analagous sympatico to the spheroidal shape?
> I've seen neither a macro nor micro view of a cross-section of a
> chondrule so I can't speak to the issue of concentric layering.
> Please excuse this question if it either "offers a keen grasp of the
> obvious" or is so "out of the ballpark", "continent", "planet", "sun
> (star) system", "gallaxy" (that's as limiting as my current unaided memory
> allows my imagination to propel itself).
> Thank you for your indulgence.
> Jerry Flaherty
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Received on Mon 14 Feb 2005 08:53:30 PM PST