[meteorite-list] Quartz in meteorites

[cdtucson at cox.net]

Bernd, List,
 I have a follow-up question;
I realize the amount of quartz found in all of these different types of meteorites is small but, why does that mean it cannot be found in larger amounts? With all due respect, Who came up with this rule? As one example in a million, even nickel in Iron meteorites varies from a few percent to as high as sixty percent and all Earth rocks with quartz have a varying degree as well from a ppm to pure; 100%. 
Thanks.
Carl Esparza
IMCA 5829

---- bernd.pauli at paulinet.de wrote: 
> Hello Folks,
> 
> 01) MONTEIRO J.F. (1989) Preliminary study of the Chaves
> howardite (Meteoritics 24-4, 1989, pp. A305-A306):
> 
> "Quartz and tridymite were observed in thin section..."
> 
> 02) RUBIN A.E. (1997) Mineralogy of meteorite groups
> (Meteoritics 32-2, 1997, 231-247, p. 241, excerpts):
> 
> "The basaltic shergottites are fine-grained rocks consisting of major pigeonite,
> augite and maskelynite, minor titanian magnetite, ilmenite, pyrrhotite and
> whitlockite, and accessory fayalite, q u a r t z , baddeleyite and chlorapatite
> within the mesostasis (McSween, 1994)."
> 
> 03) AFANASIEV S.V. et al. (2000) Dhofar 007 and Northwest Africa 011:
> Two new eucrites of different types (MAPS 35-5, 2000, Suppl., A019):
> 
> "Northwest Africa 011 is an unbrecciated achondrite unlike ... Accessories
> are metal, troilite, spinel, ilmenite, and  q u a r t z."
> 
> 04) SEMENENKO V.P. et al. (1998) The Galkiv meteorite: A new H4
> chondrite from Ukraine (MAPS 33, 1998, A193-A196):
> 
> "The meteorite contains olivine, low-Ca pyroxene, Ni-Fe, troilite, and minor amounts
> of high-Ca pyroxene, chromite, feldspathic plagioclase, phosphates, metallic Cu and
> rare grains of spinel and  q u a r t z ."
> 
> 05) ZHANG Y. et al. (1996) Pyroxene structures, cathodoluminescence and
> the thermal history of the enstatite chondrites (Meteoritics 31-1, 1996, 87-96):
> 
> "Mason (1968) suggested a maximum equilibration temperature of 870°C based
> on the presence of  q u a r t z ."
> 
> Best wishes,
> 
> Bernd
> 
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