NSF-BSF: Composition and evolution of saline fluids in the upper mantle

地球深部与我们生活的地表环境之间的联系对于维持地球的长期可居住性至关重要。例如，地球内部上地幔的盐水可能在连接深部俯冲带和地表火山活动方面发挥重要作用。这是如何发生的仍然是个谜。其中一个原因是，没有实验数据表明这种流体如何与上地幔岩石发生化学反应，尽管盐水流体保存在地球深处的钻石和岩石中。这项拟议中的研究旨在了解氯化物在盐水中的作用。例如，氯化物在上地幔条件下运输金属的潜力是非常有趣的。这个过程有多重要？随着时间的推移，对上地幔的变化、熔体的产生、大陆根的长期稳定性以及地球表面的火山活动类型有什么影响？研究这些问题将有助于揭示地球及其近地表环境的特殊特征的原因，这些特征有助于地球的可居住性，并有助于为预测其他行星的潜在可居住性提供基础。这是一个由国家科学基金会地球科学理事会（NSF-GEO）和以色列两国科学基金会（BSF）共同资助的项目，符合NSF和BSF之间谅解备忘录中的语言雅阁。该协议允许一个单一的合作建议，涉及美国和以色列的调查人员，提交和同行评审的NSF。在成功的结果NSF的优点审查和建议的认可NSF计划的奖励，每个机构的资金比例的预算和调查人员与自己的county.The总体目标的建议是了解的组成和演化的盐水流体在上地幔。一个独特的实验，热力学模拟和观测研究相结合，提出了研究的起源和作用的富氯流体金刚石形成和地幔交代。以色列参与者为该项目带来了两个重要领域的专业知识，即测量地幔岩石在氯化物溶液中溶解度所需的实验专业知识和分析钻石中流体包裹体的专业知识。这两个专业领域得到了高压-温度岩石溶解度实验室和流体包裹体分析实验室提供的资源的支持。实验的溶解度和已公布的单矿物溶解度的理论分析将与来自较低温度和压力的实验和光谱研究的数据相结合，以扩大在深层地球水（DEW）模型中金属氯化物络合物的校准。整合这些研究的结果将使流体的化学传质预测成为可能-岩石相互作用，与天然金刚石中流体和固体包裹体的成分进行比较，以测试上地幔中含盐流体的起源和演化的替代方案。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查进行评估，被认为值得支持的搜索.

Connections between the deep Earth and the surface environment where we live are crucial to maintaining the long-term habitability of the Earth. As an example, saline fluids inside the Earth in the upper mantle may play an important role in connecting subduction zones at depth and volcanism at the surface. How this happens is still mysterious. One reason for this is that there are no experimental data for how such fluids interact chemically with upper mantle rocks, even though saline fluids are preserved in diamonds and rocks from the deep Earth. The proposed research seeks to understand the role of chloride in saline fluids. For example, the potential for chloride to transport metals under upper mantle conditions is highly intriguing. How important is this process? What are the impacts on changing the upper mantle through time, the generation of melts, the long-term stability of continental roots, and the types of volcanism at the surface of Earth? Answering these questions will help unravel the reasons for the special features of Earth and its near-surface environment that contribute to Earth's habitability as well as helping to provide a basis for the prediction of the potential habitability of other planets. This is a project jointly funded by the National Science Foundation’s Directorate of Geosciences (NSF-GEO) and the Israel Binational Science Foundation (BSF) in accord with the language in the Memorandum of Understanding between the NSF and the BSF. This Agreement allows a single collaborative proposal, involving US and Israeli investigators, to be submitted and peer-reviewed by NSF. Upon successful results of the NSF merit review and recommendation by the cognizant NSF Program of an award, each Agency funds the proportion of the budget and the investigators associated with its own country.The overall objective of this proposal is to understand the composition and evolution of saline fluids in the upper mantle. A unique combination of experimental, thermodynamic modeling, and observational studies are proposed to examine the origins and roles of Cl-rich fluids in diamond formation and mantle metasomatism. The Israeli participants bring two vital areas of expertise to the project, namely the experimental expertise needed to measure the solubilities of mantle rocks in chloride solutions and the expertise in analyzing fluid inclusions in diamonds. These two areas of expertise are buttressed by the resources provided in the experimental laboratory for high pressure-temperature rock solubilities and the analytical laboratory for fluid inclusion analysis. Theoretical analysis of the experimental solubilities and published single mineral solubilities will be integrated with data from lower temperature and pressure experimental and spectroscopic studies to expand the calibration of metal-chloride complexes in the Deep Earth Water (DEW) model. Integrating the results of these studies will enable chemical mass transfer predictions of fluid-rock interaction for comparison with the compositions of fluid and solid inclusions in natural diamonds to test alternate scenarios for the origin and evolution of saline fluids in the upper mantle.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.