[FPSPACE] Outgassing of Ordinary Chondritic Material and Some of its Implications for the

[LARRY KLAES]

Astrophysics, abstract
astro-ph/0606671

From: Laura Schaefer [view email]

Date: Tue, 27 Jun 2006 22:33:19 GMT (612kb)

Outgassing of Ordinary Chondritic Material and Some of its Implications for 
the Chemistry of Asteroids, Planets, and Satellites

Authors: Laura Schaefer, Bruce Fegley, Jr

Comments: 72 pages, 17 figures, 3 tables; submitted to Icarus

We used chemical equilibrium calculations to model thermal outgassing of 
ordinary chondritic material as a function of temperature, pressure, and 
bulk compositions and use our results to discuss outgassing on asteroids and 
the early Earth. The calculations include ~1,000 solids and gases of the 
elements Al, C, Ca, Cl, Co, Cr, F, Fe, H, K, Mg, Mn, N, Na, Ni, O, P, S, Si, 
and Ti. The major outgassed volatiles from ordinary chondritic material are 
CH4, H2, H2O, N2, and NH3(the latter at conditions where hydrous minerals 
form). Contrary to widely held assumptions, CO is never the major C-bearing 
gas during ordinary chondrite metamorphism. The calculated oxygen fugacity 
(partial pressure) of ordinary chondritic material is close to that of the 
quartz-fayalite-iron (QFI) buffer. Our results are insensitive to variable 
total pressure, variable volatile element abundances, and kinetic inhibition 
of C and N dissolution in Fe metal. Our results predict that Earth's early 
atmosphere contained CH4, H2, H2O, N2, and NH3; similar to that used in 
Miller-Urey synthesis of organic compounds.

http://arxiv.org/abs/astro-ph/0606671