[meteorite-list] More Questions - meteoritics

From: Robert Beauford <wendirob_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:12 2004
Message-ID: <000701c09f5a$43af2a40$674897cc_at_wendirob>

If I understood correctly, Steven Singletary kindly explained that oxygen
fugacity refers to the measured amount of oxygen available to react in
various environments (earth, asteroids, lunar) in regards to the formation
of various lithologies (rock groups/types). This leads me to a further
question:

Shearer et al, Planetary Materials V.36 Reviews in Mineralogy states:
"The moon lacks significant water and the lithologies making up its crust
crystalized at a very low oxygen fugacity. Therefore, all lunar
lithologies thus far sampled are anhydrous (without water) and contain
elements in reduced valence states." (I believe valence states is potential
reactivity or combining power of an element (due to extra or lacking
electrons...?))

What is the significance of a reduced valence state? More or less reactive?
And why do valence states correlate to water presence or oxygen fugacity
during crystalization?

Also, I'm still trying to figure out the significance of "Mg/Fe+Mg of Bulk
Planet" in terms of planetary materials.

My most sincere thanks in advance to anyone willing to take the time to
explain.
-Robert Beauford : )
Received on Sun 25 Feb 2001 01:38:31 PM PST