Nominally hydrous magmatism on the Moon
Nominally hydrous magmatism on the Moon
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DOI：
10.1073/pnas.1006677107
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发表时间：
2010-06-22
影响因子：
11.1
通讯作者：
Hemley, Russell J.
中科院分区：
文献类型：
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作者：
McCubbin, Francis M.;Steele, Andrew;Hemley, Russell J.
在过去的 40 年里，月球被描述为几乎没有本土水。然而，最近出现的月球表面和月球内部存在水的证据，使人们对这一长期存在的月球教条产生了质疑。在本研究中，通过二次离子质谱分析了来自三个不同月球样品的磷灰石 [Ca-5(PO4)(3)(F,Cl,OH)] 中的羟基（以及氟化物和氯化物），以获得月球内部水丰度的定量限制。这项工作证实，来自月球的磷灰石中存在数百至数千 ppm 的水（结构形式为羟基）。此外，所研究的两个样本可能含有岩浆过程中保存下来的水，这表明这些水是月球固有的。许多不同类型的月球岩石中的磷灰石中存在羟基，这表明水可能在月球内部无处不在，可能早在月球形成时就存在。对月球磷灰石的水含量分析表明，其月球来源区域的最低水含量范围为 64 ppb 至 5 ppm H2O。这个含水量下限范围比之前报道的月球整体含水量至少大两个数量级，而实际源区含水量可能要高得多。
For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca-5(PO4)(3)(F,Cl,OH)] from three different lunar samples in order to obtain quantitative constraints on the abundance of water in the lunar interior. This work confirms that hundreds to thousands of ppm water (of the structural form hydroxyl) is present in apatite from the Moon. Moreover, two of the studied samples likely had water preserved from magmatic processes, which would qualify the water as being indigenous to the Moon. The presence of hydroxyl in apatite from a number of different types of lunar rocks indicates that water may be ubiquitous within the lunar interior, potentially as early as the time of lunar formation. The water contents analyzed for the lunar apatite indicate minimum water contents of their lunar source region to range from 64 ppb to 5 ppm H2O. This lower limit range of water contents is at least two orders of magnitude greater than the previously reported value for the bulk Moon, and the actual source region water contents could be significantly higher.