The canonical water cycle assumes that all water entering the subsurface to form groundwater eventually reenters the surface water cycle by discharge to lakes, streams, and oceans. Recent discoveries in groundwater dating have challenged that understanding. Here we introduce a new conceptual framework that includes the large volume of water that is estimated to account for 30–46% of the planet's groundwater but that is not yet incorporated in the traditional water cycle. This immense hidden hydrogeosphere has been overlooked to date largely because it is stored deeper in the crust, on long timescales ranging from tens of thousands to more than one billion years. Here we demonstrate why understanding of this deep, old groundwater is critical to society's energy, resource, and climate challenges as the deep hydrogeosphere is an important target for exploration for new resources of helium, hydrogen, and other elements critical to the green energy transition; is under investigation for geologic repositories for nuclear waste and for carbon sequestration; and is the biome for a deep subsurface biosphere estimated to account for a significant proportion of Earth's biomass. ▪ We provide a new conceptual framework for the hidden hydrogeosphere, the 30–46% of groundwater previously unrecognized in canonical water cycles. ▪ Geochemico-statistical modeling groundwater age distributions allows deconvolution of timing, rates, and magnitudes of key crustal processes. ▪ Understanding and modeling this deep, old groundwater is critical to addressing society's energy, resource, and climate challenges.Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 52 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

中文翻译：

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隐藏的水文地质圈：深层地下水对行星水循环的贡献

规范水循环假设所有进入地下形成地下水的水最终通过排放到湖泊、溪流和海洋而重新进入地表水循环。最近地下水测年的发现挑战了这种认识。在此，我们介绍一个新的概念框架，其中包括估计占地球地下水 30-46% 但尚未纳入传统水循环的大量水。这个巨大的隐藏水气圈迄今为止一直被忽视，很大程度上是因为它储存在地壳深处，时间尺度从数万年到超过10亿年不等。在这里，我们展示了为什么了解这种古老的深层地下水对于社会的能源、资源和气候挑战至关重要，因为深层水地质圈是勘探氦、氢和其他对绿色能源转型至关重要的新资源的重要目标；正在调查核废料和碳封存地质处置库；是深层地下生物圈的生物群落，估计占地球生物量的很大一部分。 ▪ 我们为隐藏的水圈提供了一个新的概念框架，即以前在规范水循环中未被识别的地下水的 30-46%。 ▪ 地下水年龄分布的地球化学统计建模允许对关键地壳过程的时间、速率和幅度进行反卷积。 ▪ 了解并模拟这种古老的深层地下水对于解决社会的能源、资源和气候挑战至关重要。《地球与行星科学年度评论》第 52 卷的预计最终在线发布日期为 2024 年 5 月。请参见 http://www .annualreviews.org/page/journal/pubdates 了解修订后的估计。