Light element geochemistry of the Apollo 15 site
Light element geochemistry of the Apollo 15 site
复制标题
阿波罗 15 号站点的轻元素地球化学
DOI：
10.1016/0016-7037(75)90167-2
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
C. Petrowski
中科院分区：
文献类型：
--
作者：
I. Kaplan;J. Kerridge;C. Petrowski
阿波罗16号站点土壤中一些轻元素的丰度和同位素组成的显著变化被解释为不同程度的太阳风暴露的原始，近似，均匀的风化层。土壤中的碳丰度是兼容的模型，在该模型中建立平衡，10 4-10 5年后，太阳风输入和H剥离损失之间。然而，这个模型并不能解释所观察到的碳同位素分布，这表明其他来源的碳或其他过程，或两者兼而有之，也很重要。阿波罗16号岩石中的碳丰度（平均40 ppm）高于其他着陆点，尽管其同位素组成为− 35< δ 13 C<− 16%。PDB是正常的。土壤中N的丰度以及较小程度上的He和H与C相关，因为太阳风H原位还原土著Fe 2+导致金属Fe的一部分也与C相关。圆角土壤67461显然含有相对未分馏形式的太阳风C和N，产生太阳风的上限（δ 13 C为− 16%，PDB和太阳风中的C N值为3.4。阿波罗16号地点的硫代表了一个悖论，尽管土壤中的丰度显然受当地岩石S含量的控制，但除了一个样品外，它们还与δ 34 S相关，而δ 34 S本身显然受表面暴露年龄的控制。提出了一个复杂的月球S周期。
Pronounced variations in abundances and isotopic compositions of some light elements in soils from the Apollo 16 site are interpreted in terms of differing degrees of solar wind exposure for an originally, and approximately, homogeneous regolith. Carbon abundances in soils are compatible with a model in which equilibrium is established, after 10 4-10 5 yr, between solar wind input and loss by H stripping. However, this model does not explain the observed C isotopic distribution, suggesting that other sources of C or other processes, or both, are also important. Carbon abundances in rocks from Apollo 16 are higher (average 40 ppm) than at other landing sites although their isotopic compositions,− 35< δ 13 C<− 16%. PDB, are normal. Abundances of N and, to a less extent, He and H in soils correlate with C as does a fraction of metallic Fe attributed to in situ reduction of indigenous Fe 2+ by solar wind H. Fillet soil 67461 apparently contains solar wind C and N in a relatively unfractionated form, yielding an upper limit to solar wind (δ 13 C of− 16%., PDB and a value of 3.4 for C N in the solar wind. Sulfur at the Apollo 16 site represents a paradox in that, although abundances in soils are apparently controlled by local rock S contents, they also correlate, for all but one sample, with δ 34 S, which itself is apparently controlled by surface exposure age. A complex lunar S cycle is suggested.