[meteorite-list] New Arizona Meteorite!

[tracy latimer]

I can't say this with any definiteness, but I don't believe any "new" (i.e., 
unweathered) chondrules show signs of concentric layering, only ones that 
have been exposed to Earth's atmosphere and have suffered degradation from 
moisture.  I can't point to any example I have seen that shows anything like 
growth rings that have definitely formed outside Earth conditions; they all 
imply forming at once, rather than in successive buildups.  This completely 
ignores the question of armored chondrules, however.

Tracy Latimer
>
>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.