History and Evolution of Volatiles in the Earth-Moon System

最近对月球样本的研究证实，月球上存在大量水和其他挥发物(例如，Hauri等人，2017年)。这些发现被用来修正月球形成模型，改变我们对太阳系历史早期(Barnes等人，2016a)挥发物来源和输送到地月系统的时间的理解。许多月球挥发物的研究都是在原位进行的，研究对象是熔体包裹体、名义上的无水矿物以及晶体结构中含有水的矿物磷灰石(如羟基)和其他挥发性元素(如F、Cl、S)。其中，磷灰石是各种月球岩石中最常见的挥发分相。月球磷灰石的氢和氯同位素特征揭示了行星过程(例如岩浆脱气、宇宙射线散裂、撞击诱导的交代作用)之间的复杂相互作用，需要更好地了解这些过程，以便识别和量化地月系统的不同挥发物来源(图1)。目前，缺乏将岩石学与行星样品中挥发分的现场地球化学测量相结合的深入研究。这一方法对于解释现有的和任何新的数据集，以限制各种太阳系进程并评估小行星和彗星在向地月系统输送水方面的作用至关重要(例如，Marty，2012)。

Recent research on lunar samples has confirmed significant presence of water and other volatiles in the Moon (e.g., Hauri et al., 2017). These findings are being used to revise Moon formation models and transform our understanding of the sources and timing of delivery of volatiles to the Earth-Moon system during earliest periods of the Solar System history (Barnes et al., 2016a).Much of the lunar volatiles research has been carried out in-situ on melt inclusions, nominally anhydrous minerals and the mineral apatite that contains water (as hydroxyl) and other volatile elements (e.g., F, Cl, S) in its crystal structure. Of these, apatite is the most common volatile-bearing phase across a wide variety of lunar rocks. The H and Cl isotope signatures of lunar apatite reveal complex interplay between planetary processes (e.g., magma degassing, cosmic ray spallation, impact-induced metasomatism) that need to be better understood in order to identify and quantify different sources of volatiles to the Earth-Moon system (Fig. 1). Currently, an in-depth study linking petrography with in-situ geochemical measurements for volatiles in planetary samples is lacking. This approach is key to interpreting existing and any new dataset for constraining various solar system processes and evaluate the role asteroids and comets in delivering water to the Earth-Moon system (e.g., Marty, 2012).