Replication Data for: Controls on determining the bulk water content of the Moon.

The Moon is much wetter than previously thought. The estimated bulk H2O concentrations based on the analyses of H2O in lunar materials show a wide range from 5 to 1650 ppm. To better constrain bulk H2O in the lunar magma ocean (LMO), we model LMO crystallization and vary DH (concentration of H2O in LMO mineral/concentration of H2O in melt), interstitial melt fraction, and initial LMO depth. We take the highest and lowest values of DH reported in the literature for the LMO minerals. We assess the bulk H2O content required in the initial magma ocean to satisfy two observational constraints: (1) H2O measured in plagioclase grains from ferroan anorthosites and (2) crustal mass from GRAIL. We find that the initial bulk LMO H2O that best explains the H2O content in crustal plagioclase is strongly dependent on DH rather than interstitial melt fractions or initial LMO depths, with a drier magma ocean (10 ppm H2O) being favored with higher DH and a wetter magma ocean (100–1000 ppm H2O) with lower DH. This underscores the importance of constraining DH specific to lunar conditions in future studies. We also demonstrate that crustal mass is not an effective hygrometer.

月球的含水量远高于此前的认知。基于月球物质中水（H₂O）分析得出的整体水浓度估算值范围较广，介于5至1650 ppm之间。为了更准确地限定月球岩浆洋（lunar magma ocean, LMO）中的整体水含量，我们对LMO的结晶过程进行建模，并调整分配系数DH（LMO矿物中的水浓度与熔体中的水浓度之比）、间隙熔体分数以及初始LMO深度。我们采用文献中报道的LMO矿物DH值的最高与最低范围。我们评估了初始岩浆洋中满足两项观测约束所需的整体水含量：（1）从铁镁质斜长岩中的斜长石颗粒测得的水含量；（2）由GRAIL获得的地壳质量。我们发现，能最佳解释地壳斜长石中水含量的初始LMO整体水含量，强烈依赖于DH而非间隙熔体分数或初始LMO深度：当DH较高时，更支持较干燥的岩浆洋（水含量为10 ppm）；而DH较低时，则对应较湿润的岩浆洋（水含量为100–1000 ppm）。这凸显了在未来研究中限定月球特定条件下DH值的重要性。我们还证明，地壳质量并非有效的湿度计。