Experimental Study of Noble Gas Behavior in the Mantle

地球内部的运动控制和组织了许多在地表发生的事情。从地震和火山，到石油和矿产，甚至生命本身的进化；人类生活的世界在很大程度上是地球内部深层过程的产物。因为人们不能直接对地球深处进行采样，所以人们必须使用间接的物理和化学测量来了解我们脚下发生的事情。这项拟议的研究旨在利用熔岩中惰性气体(He、Ne、Ar、Kr、Xe)及其同位素的浓度作为探测对我们生活产生如此大影响的高压过程的探针，以加深我们对地球内部运动和组成的理解。由于它们缺乏电荷，通常认为惰性气体是惰性的，不被保留在地幔矿物中。许多关于地球的范例将这作为一个关键假设：从理解地幔对流的结构到量化地球的挥发性成分。然而，最近的高压实验研究表明，事实上惰性气体在地幔中的溶解度高得令人惊讶，这可能需要一系列理论来修正。事实上，极少有实验测量稀有气体在地幔条件下的行为。利用新的分析和实验进展，这项研究将测量惰性气体在一系列地幔矿物中的分配和扩散系数，其中许多是首次测量，包括斜方辉石、石榴石、斜方辉石、环状辉石和辉石。将使用一系列高压设备(活塞-气缸、多个砧座、内部加热气体压力)来产生20 Gpa以上的压力和高达2000摄氏度的温度，以模拟上地幔和下地幔的条件。样品将用新一代激光烧蚀质谱仪进行测量。这一史无前例的数据集将被用来重新评估目前关于地球结构和组成的想法。

The motions of the Earth's interior control and organize much of what goes on at the surface. From earthquakes and volcanoes, to oil and mineral deposits, even the evolution of life itself; the world humans live in is largely the product of the deep processes within our planet's interior. Because one cannot directly sample the deep Earth, one has to use indirect physical and chemical measurements to understand what is happening below our feet. The proposed study seeks to further our understanding of the inner motions and composition of the Earth's interior using the concentrations of noble gases (He, Ne, Ar, Kr, Xe) and their isotopes in lavas as probes of the high pressure processes that have such a large effect on our lives.Due to their lack of charge, it has generally been assumed that noble gases are inert and are not retained in mantle minerals. A number of paradigms about the Earth use this as a key assumption: from the understanding structure of mantle convection to quantifying the volatile content of the planet. However, recent high-pressure experimental studies suggest that in fact noble gases have surprisingly high solubilities in the mantle, potentially requiring a wide range of theories to be revamped. In fact, there are few experimental measurements of noble gas behavior at mantle conditions. Utilizing new analytical and experimental advances, this study will measure the partitioning and diffusivities of noble gases in a range of mantle minerals, many for the first time, including orthopyroxene, garnet, wadsleyite, ringwoodite and majorite. A range of high-pressure devices (piston-cylinder, multi-anvil, internally-heated gas pressure) will be employed to produce pressures over 20 GPa and temperatures up to 2000 oC, simulating conditions in the upper and lower mantle. Samples will be measured by new generation laser-ablation mass spectrometry. The unprecedented data set will be used to reevaluate current ideas about the structure and composition of the Earth.