"Follow the Water": Controls on the Distribution and Preservation of Habitability from Water-Rock Interactions in the Earth's Deep Crust

“追随水流”：地壳深处水-岩相互作用对宜居性分布和保存的控制

• 批准号: RGPIN-2018-06149
• 负责人: SherwoodLollar, Barbara
• 金额: $ 6.85万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=692494
• 关键词: Follow; Water; Controls; Distribution; Preservation

Summary of Proposal ***Our understanding of the Earth, as scientists, engineers, policy makers and public citizens, can inadvertently be constrained by the fact that human life is just a thin veneer on the surface of the Blue Planet. Fundamental challenges remain concerning the complexities of chemical, physical (and biological) interactions in the Earth's subsurface - in particular the nature of subsurface water the Earth's Deep Hydrosphere. For instance, geochemists have long relied on fluid inclusions - microscopic time capsules of fluid and gas encased in host rocks and fracture minerals - to access preserved samples of ore-forming fluids, metamorphic fluids, and remnants of the ancient atmosphere and hydrosphere. Until recently, macroscopic (flowing) groundwaters were thought to reflect only much younger periods of water-rock reaction and Earth history, due to dilution with large volumes of younger fluids recharging from surface. Over the past 6 years we have explored and expanded our understanding of the depth, distribution, storage and residence time of groundwaters in the Precambrian crust that constitutes > 70% of the Earth's continental lithosphere accessed by our team via working mines, and underground research laboratories worldwide. Our discovery of groundwaters that preserve components that are millions and even > a billion of years old provides the opportunity for new suites of samples for understanding the evolution of the Earth's hydrosphere and atmosphere, challenges our understanding of the habitability of Earth, and informs our thinking about possible groundwater and habitability beneath Mars, and on the icy planets and moons elsewhere in the solar system. As an isotope geochemist and hydrogeologist, my leadership and core contributions to this program are to provide insight, interpretation and critical constraints from the geochemistry and isotopic signatures (using both reactive CHO elements that record the history of chemical and biologically-mediated reactions; and conservative noble gases that identify origin and mixing of components of different provenance) for the fluids and gases that define the hydrogeology and habitability of the deep Earth. In addition to advancing fundamental understanding for NSE, and capturing public imagination about the deep Earth, this research has important practical implications - potentially providing information about ore-forming processes, providing new technology transfer re understanding the degree of isolation of deep subsurface fluids (pertinent to proposed nuclear waste disposal, and carbon capture and storage projects); and providing novel detailed information about the nature of highly saline deep subsurface fluids and gases that will be encountered as humans explore and investigate the deep continental lithosphere. Such a program is well suited to the GeoSciences EG 1506's broad expertise.**

提案摘要***作为科学家、工程师、政策制定者和公众公民，我们对地球的理解可能会无意中受到这样一个事实的限制：人类生命只是蓝色星球表面的一层薄薄的饰面。地球地下化学、物理（和生物）相互作用的复杂性仍然存在基本挑战，特别是地球深层水圈地下水的性质。例如，地球化学家长期以来一直依靠流体包裹体（包裹在主岩和裂缝矿物中的流体和气体的微观时间胶囊）来获取保存的成矿流体、变质流体以及古代大气和水圈残留物的样本。直到最近，宏观（流动的）地下水被认为只反映了水-岩石反应和地球历史的更年轻时期，这是由于大量从地表补给的较年轻的流体引起的稀释。在过去的 6 年里，我们探索并扩大了对前寒武纪地壳地下水的深度、分布、储存和停留时间的了解，我们的团队通过世界各地的工作矿山和地下研究实验室访问了前寒武纪地壳地下水，占地球大陆岩石圈的 70% 以上。我们发现的地下水保存了数百万年甚至超过10亿年的成分，为获取新样本提供了机会，以了解地球水圈和大气的演化，挑战了我们对地球宜居性的理解，并为我们思考火星下方以及太阳系其他地方的冰冷行星和卫星上可能存在的地下水和宜居性提供了信息。作为一名同位素地球化学家和水文地质学家，我对这个项目的领导和核心贡献是为定义水文地质和可居住性的流体和气体提供来自地球化学和同位素特征的见解、解释和关键约束（使用记录化学和生物介导反应历史的反应性 CHO 元素；以及识别不同来源成分的来源和混合的保守惰性气体） 地球深处。除了增进对 NSE 的基本了解并激发公众对地球深处的想象力之外，这项研究还具有重要的实际意义 - 可能提供有关成矿过程的信息，提供新技术转让以重新了解深层地下流体的隔离程度（与拟议的核废料处理以及碳捕获和储存项目相关）；并提供有关人类探索和调查深层大陆岩石圈时将遇到的高盐度深层地下流体和气体性质的新颖详细信息。这样的程序非常适合地球科学 EG 1506 广泛的专业知识。**