The origin of water in the primitive Moon as revealed by the lunar highlands samples
The origin of water in the primitive Moon as revealed by the lunar highlands samples
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DOI：
10.1016/j.epsl.2014.01.015
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发表时间：
2014-03-15
影响因子：
5.3
通讯作者：
Russell, Sara S.
中科院分区：
文献类型：
--
作者：
Barnes, Jessica J.;Tartese, Romain;Russell, Sara S.
最近在月球表面和来自月球内部的样本中发现了含氢（H）的物种，这使得我们对月球水存量的理解有必要进行范式转变，月球以前被认为是一个“非常干燥”的行星体。大多数基于样本的研究都集中在评估年轻月海玄武岩和火山碎屑玻璃的含水量，这些都是月球地幔部分熔融的产物。相比之下，很少有人注意到月球高地岩石中的水的库存和来源，这些岩石是实验室研究中最古老和最原始的材料，并且有可能揭示地球-月球系统中水的原始历史。在这里，我们报告原位测量的羟基（OH）含量和氢同位素组成的矿物磷灰石从四个月球高地样本（两个诺利特，troctolite，花岗岩碎屑）收集在阿波罗任务。除了磷灰石中测得的OH含量接近我们的分析检测极限且其H同位素组成似乎受到二次过程的严重损害的troctolite之外，我们在花岗岩碎屑中测得了高达2200 ppm的OH，加权平均Δ D类似于-105 +/-130 ppm，在两种诺丽石（77215和78235）中高达3400 ppm的OH，加权平均Δ D值分别为-281 +/-49ppm和-27 +/-98ppm。磷灰石在花岗岩碎屑和norites的特点是更高的OH含量比迄今为止已报道的高地样品，并具有H同位素组成类似的陆地材料和一些碳质方解石，提供了一个最有力的证据，但在地球-月球系统的水的共同起源。此外，在一些最早形成的月球地壳样本中存在着与陆地有密切关系的水，这表明要么原始陆地水在月球撞击后幸存下来，要么水是在月球吸积后立即通过一个共同的来源添加到地月系统中的。(C)2014作者由Elsevier出版。这是CC BY许可下的开放获取文章（http：//creativecommons.org/licenses/by/3.0/）。
The recent discoveries of hydrogen (H) bearing species on the lunar surface and in samples derived from the lunar interior have necessitated a paradigm shift in our understanding of the water inventory of the Moon, which was previously considered to be a 'bone-dry' planetary body. Most sample-based studies have focused on assessing the water contents of the younger mare basalts and pyroclastic glasses, which are partial-melting products of the lunar mantle. In contrast, little attention has been paid to the inventory and source(s) of water in the lunar highlands rocks which are some of the oldest and most pristine materials available for laboratory investigations, and that have the potential to reveal the original history of water in the Earth-Moon system. Here, we report in-situ measurements of hydroxyl (OH) content and H isotopic composition of the mineral apatite from four lunar highlands samples (two norites, a troctolite, and a granite clast) collected during the Apollo missions. Apart from troctolite in which the measured OH contents in apatite are close to our analytical detection limit and its H isotopic composition appears to be severely compromised by secondary processes, we have measured up to similar to 2200 ppm OH in the granite clast with a weighted average delta D of similar to-105 +/- 130 parts per thousand, and up to similar to 3400 ppm OH in the two norites (77215 and 78235) with weighted average delta D values of -281 +/- 49 parts per thousand and -27 +/- 98 parts per thousand, respectively. The apatites in the granite clast and the norites are characterised by higher OH contents than have been reported so far for highlands samples, and have H isotopic compositions similar to those of terrestrial materials and some carbonaceous chondrites, providing one of the strongest pieces of evidence yet for a common origin for water in the Earth-Moon system. In addition, the presence of water, of terrestrial affinity, in some samples of the earliest-formed lunar crust suggests that either primordial terrestrial water survived the aftermath of the putative impact-origin of the Moon or water was added to the Earth-Moon system by a common source immediately after the accretion of the Moon. (C) 2014 The Authors. Published by Elsevier By. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).