Outgassing of ordinary chondritic material and some of its implications for the chemistry of asteroids, planets, and satellites
Outgassing of ordinary chondritic material and some of its implications for the chemistry of asteroids, planets, and satellites
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普通球粒陨石材料的放气及其对小行星、行星和卫星化学的一些影响
DOI：
10.1016/j.icarus.2006.09.002
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发表时间：
2006
期刊：
影响因子：
3.2
通讯作者：
Jr.
中科院分区：
文献类型：
--
作者：
L. Schaefer;B. Fegley;Jr.
我们使用化学平衡计算来模拟普通球粒陨石材料作为温度、压力和体积成分的函数的热放气，并使用我们的结果来讨论小行星和早期地球的放气。计算包括约 1000 种元素 Al、C、Ca、Cl、Co、Cr、F、Fe、H、K、Mg、Mn、N、Na、Ni、O、P、S、Si 和 Ti 的固体和气体。普通球粒陨石材料中释放的主要挥发物是 CH4、H2、H2O、N2 和 NH3（后者在含水矿物形成的条件下）。与广泛持有的假设相反，CO 从来都不是普通球粒陨石变质作用期间的主要含碳气体。计算出的普通球粒陨石材料的氧逸度（分压）与石英-铁橄榄石-铁（QFI）缓冲液的氧逸度（分压）接近。我们的结果对可变的总压、可变的挥发性元素丰度以及 C 和 N 在 Fe 金属中溶解的动力学抑制不敏感。我们的研究结果预测，地球早期大气中含有 CH4、H2、H2O、N2 和 NH3；类似于有机化合物的 Miller-Urey 合成中使用的方法。
We used chemical equilibrium calculations to model thermal outgassing of ordinary chondritic material as a function of temperature, pressure, and bulk composition and use our results to discuss outgassing on asteroids and the early Earth. The calculations include ∼1000 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.