An analysis of Apollo lunar soil samples 12070,889, 12030,187, and 12070,891: Basaltic diversity at the Apollo 12 landing site and implications for classification of small-sized lunar samples
An analysis of Apollo lunar soil samples 12070,889, 12030,187, and 12070,891: Basaltic diversity at the Apollo 12 landing site and implications for classification of small-sized lunar samples
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阿波罗月球土壤样本 12070,889、12030,187 和 12070,891 的分析：阿波罗 12 号着陆点的玄武岩多样性及其对小型月球样本分类的影响
DOI：
10.1111/maps.12689
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发表时间：
2016
影响因子：
2.2
通讯作者：
Alexander L
中科院分区：
文献类型：
--
作者：
Alexander L
月海玄武岩提供了对月球内部成分多样性的见解。来自月球风化层的玄武岩碎片可能会从以前没有访问过的月球地区采样熔岩流，从而增加我们对月球地质演化的了解。作为阿波罗12号着陆点玄武岩多样性研究的一部分，这里提供了13个玄武岩芯片的详细岩石学和地球化学数据。除了散装化学，我们已经分析了主要的，次要的，微量元素化学的矿物相突出玄武岩群体之间的差异。在样品含有橄榄石的情况下，可以计算平衡母体熔体镁数（Mg#;原子Mg/[Mg + Fe]）以估计母体熔体组成。钛铁矿和斜长石的化学成分也可以决定玄武岩组之间的差异。我们的结论是，大约1-2毫米大小的样品可以被分类，提供适当的矿物相（橄榄石，斜长石，钛铁矿）的存在。当样品是细粒的（粒度<0.3 mm）时，“配对样本检验”可以提供特定样品和已知月球玄武岩之间的统计比较。在这里分析的碎片中，发现三个属于以前确定的橄榄石和钛铁矿玄武岩套件，四个属于褐变玄武岩套件，一个是橄榄石堆晶岩，两个不能归类，因为它们的粗粒度和缺乏适当的矿物相。我们的方法引入了可用于调查小样本量的方法（即，细粒），以调查熔岩流多样性和岩石学意义。
Lunar mare basalts provide insights into the compositional diversity of the Moon's interior. Basalt fragments from the lunar regolith can potentially sample lava flows from regions of the Moon not previously visited, thus, increasing our understanding of lunar geological evolution. As part of a study of basaltic diversity at the Apollo 12 landing site, detailed petrological and geochemical data are provided here for 13 basaltic chips. In addition to bulk chemistry, we have analyzed the major, minor, and trace element chemistry of mineral phases which highlight differences between basalt groups. Where samples contain olivine, the equilibrium parent melt magnesium number (Mg#; atomic Mg/[Mg + Fe]) can be calculated to estimate parent melt composition. Ilmenite and plagioclase chemistry can also determine differences between basalt groups. We conclude that samples of approximately 1–2 mm in size can be categorized provided that appropriate mineral phases (olivine, plagioclase, and ilmenite) are present. Where samples are fine‐grained (grain size <0.3 mm), a “paired samplest‐test” can provide a statistical comparison between a particular sample and known lunar basalts. Of the fragments analyzed here, three are found to belong to each of the previously identified olivine and ilmenite basalt suites, four to the pigeonite basalt suite, one is an olivine cumulate, and two could not be categorized because of their coarse grain sizes and lack of appropriate mineral phases. Our approach introduces methods that can be used to investigate small sample sizes (i.e., fines) from future sample return missions to investigate lava flow diversity and petrological significance.