EaGER: Inclusions of fluid-related minerals in diamonds from the transition zone or lower mantle

虽然地球表面可以很容易地在许多尺度上观察到，但地球内部是不透明的，无法进入。只有少数矿物和岩石样品来自100公里以上的深度。 天然钻石不仅是我们所知的最坚硬的天然材料，也是我们直接探索地球内部更深处的最宝贵资源。 这项探索性研究早期资助（EaGER）将支持对一些富含含流体矿物（如冰和方解石）的珍贵钻石包裹体的研究。该项目将利用最先进的光谱工具，探索研究不寻常金刚石包裹体的新方法。EaGER的目的是扩大最近的研究，这些研究报告了来自非洲和中国的钻石中存在冰-VII的包裹体。其他流体相关的结晶沉淀物，如镁方解石和岩盐的包裹体已被确定，并预计有5 - 12 GPa和高达25 GPa的残余压力。其他高余压矿物包裹体，如钛铁矿和钽铁矿，也被认为是可能在过渡带和下地幔中形成的包裹体。EaGER将扩展初步研究，通过使用同步加速器微XRD和XRF，光谱学和随后的EPMA（如适用）分析大量金刚石包裹体，来限制过渡区流体的压力和温度状态。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标准进行评估，被认为值得支持。

Although the surface of the Earth can be easily observed at many scales, the interior of the Earth is opaque and not accessible. There are only a small number of samples of minerals and rocks that derive from depths greater than 100 km. Natural diamonds are not only the hardest natural materials we know but also our most valuable resources for direct interrogation of greater depths in the Earth's interior. This Early Grant for Exploratory Research (EaGER) will support the study of a few precious diamond inclusions that are rich in fluid-bearing minerals, such as ice and calcite. The project will explore new methods in the study of unusual diamond inclusion, using state-of-the-art spectroscopic tools. The purpose of this EaGER is to expand on recent studies that have reported the occurrence of inclusions of ice-VII in diamonds from locations in Africa and China. Other inclusions of fluid-related crystalline precipitates such as magnesian calcite and halite have been identified and are expected to have residual pressures of 5-12 GPa and up to 25 GPa. Other inclusions of minerals of high residual pressure such as ilmenite and taenite have also been identified as inclusions that might have formed within the Transition Zone and lower mantle. This EaGER will extend the preliminary study to constrain pressure- and temperature regimes of fluid occurrences in the Transition Zone by analyzing a larger number of diamond inclusions using synchrotron micro-XRD and-XRF, optical spectroscopy, and subsequent EPMA wherever applicable. The results should contribute to to our understanding of the global water- and carbon budget by using an entirely combination of methods.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.