"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.**

建议摘要*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在不经意间受到这样一个事实的限制，即人类的生命只是蓝色星球表面的一层薄薄的外表。基本的挑战仍然涉及地球次表层化学、物理(和生物)相互作用的复杂性--特别是地下水资源的性质--地球深层水圈。例如，地球化学家长期以来一直依靠流体包裹体--包裹在主岩和裂隙矿物中的流体和气体的微观时间胶囊--来获取成矿流体、变质流体和古代大气和水圈的残留物的保存样本。直到最近，宏观的(流动的)地下水被认为只反映了水-岩反应和地球历史的年轻得多的时期，这是因为大量年轻的流体从地表回流而被稀释。在过去的6年里，我们探索并扩大了我们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正在开采的矿山和地下研究实验室进入了地球大陆岩石圈的70%。我们发现的地下水保存了数百万年甚至10亿年前的成分，这为理解地球水圈和大气的演化提供了新的样本，挑战了我们对地球宜居性的理解，并启发了我们对火星下可能的地下水和宜居性的思考，以及太阳系其他地方结冰的行星和卫星上的可能性。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地球深部水文地质和宜居性的流体和气体的地球化学和同位素特征(使用记录化学和生物中介反应历史的反应性CHO元素；以及确定不同来源成分的来源和混合的保守惰性气体)提供洞察、解释和关键限制。除了促进对NSE的基本了解并激发公众对地球深部的想象外，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，提供新的技术转让以帮助人们重新了解深部地下流体的隔离程度(与拟议的核废料处理及碳捕获和储存项目有关)，并提供有关在人类探索和调查大陆岩石圈深部时将遇到的高盐度深部地下流体和气体性质的新的详细信息。这样的程序非常适合地球科学EG1506‘S广博的专业知识。**