Abstract During the Hadean, Earth recovered from the Moon-forming giant impact, became covered with liquid water oceans, and witnessed the onset of plate tectonics and life. Quantifying the abundances, distribution, and chemical states of water in the atmosphere, on the surface, and in the interior of the early Earth is essential to constrain the early evolution of System Earth. Assessing these parameters is hampered by the general dearth of early Earth samples, the difficulty of distinguishing primary signatures from later alteration processes in such samples, leading to large uncertainties on the influx and outflux of water to and from the early Earth. Given the close proximity of Earth and Moon, constraints on the early hydrogen cycle in the Moon may reflect coeval aspects of the water cycle on early Earth. Here, we assess constraints on the lunar water cycle from the time the Moon formed until the end of late accretion at ~3.8 Ga, and implications of these constraints for the early Earth water budget. Dynamic accretion models suggest the Moon initially contained ~455 ppm of water. Recent experimental studies of lunar magma ocean crystallization suggest similarly substantial initial lunar water contents. Hydrogen concentration measurements in lunar plagioclase crystals derived from the magma ocean illustrate that the Moon experienced significant degassing during the solidification of the lunar magma ocean (thought to have occurred between 4.5 and ~ 4.3 Ga). Hydrogen and chlorine systematics in lunar magmatic apatite grains formed between ~4.1 Ga and ~ 3 Ga indicate that lunar hydrogen reservoirs were replenished by volatile delivery during late accretion (~4.1–3.8 Ga), after which the water abundance of the Moon stabilized. Using this knowledge of the lunar water cycle to model Earth's early water budget leads to two scenarios that are consistent with the observed present-day terrestrial water content of 1000–3000 ppm: (1) Earth contained significantly more water than the Moon-forming material immediately after the giant impact, suggesting hydrogen heterogeneity in the initial Earth-Moon system; (2) Earth did not experience significant degassing in the aftermath of the giant impact, and the late accretion mass added to Earth was large and water-rich

中文翻译：

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月球氢循环演化对早期地球水收支的限制

摘要 在冥界时期，地球从月球形成的巨大撞击中恢复，被液态水海洋覆盖，见证了板块构造和生命的开始。量化早期地球大气、地表和内部水的丰度、分布和化学状态对于限制地球系统的早期演化至关重要。评估这些参数受到早期地球样本普遍缺乏的阻碍，很难区分这些样本中的主要特征与后期的蚀变过程，导致进出早期地球的水流入和流出存在很大的不确定性。鉴于地球和月球非常接近，月球早期氢循环的限制可能反映了早期地球上水循环的同期方面。这里，我们评估了从月球形成到晚期吸积结束（约 3.8 Ga）对月球水循环的限制，以及这些限制对早期地球水收支的影响。动态吸积模型表明月球最初含有约 455 ppm 的水。最近对月球岩浆海洋结晶的实验研究表明，月球初始含水量也同样很大。来自岩浆海洋的月球斜长石晶体中的氢浓度测量表明，月球在月球岩浆海洋的凝固过程中经历了显着的脱气（据认为发生在 4.5 和 ~ 4.3 Ga 之间）。月球岩浆磷灰石颗粒中的氢和氯系统学形成于~4. 1 Ga 和~3 Ga 表明月球氢库在晚期吸积过程中（~4.1-3.8 Ga）通过挥发物输送得到补充，此后月球的水丰度趋于稳定。使用月球水循环的这些知识来模拟地球早期的水收支平衡会导致两种情景，这两种情景与目前观测到的 1000-3000 ppm 的地球含水量一致：(1) 地球含有的水明显多于形成月球的物质紧接在巨大撞击之后，表明初始地月系统中的氢异质性；(2) 地球在大撞击之后没有经历明显的脱气，后期添加到地球的吸积质量大且富含水 使用月球水循环的这些知识来模拟地球早期的水收支平衡会导致两种情景，这两种情景与目前观测到的 1000-3000 ppm 的地球含水量一致：(1) 地球含有的水明显多于形成月球的物质紧接在巨大撞击之后，表明初始地月系统中的氢异质性；(2) 地球在大撞击之后没有经历明显的脱气，后期添加到地球的吸积质量大且富含水 使用月球水循环的这些知识来模拟地球早期的水收支平衡会导致两种情景，这两种情景与目前观测到的 1000-3000 ppm 的地球含水量一致：(1) 地球含有的水明显多于形成月球的物质紧接在巨大撞击之后，表明初始地月系统中的氢异质性；(2) 地球在大撞击之后没有经历明显的脱气，后期添加到地球的吸积质量大且富含水