Noble Gas Studies of the Pacific Mantle

摘要（0525864）：本研究将扩大在加拉帕戈斯热点西侧费尔南迪诺火山最近回收的海底玻璃中重惰性气体（Ne, Ar, Xe）和CO2的分析数量。这些样品具有不同寻常的He同位素比率，表明费尔南迪诺火山直接位于热点的中心融化区之上。在费尔南迪诺玻璃中观察到的稀有气体同位素比率被认为来自地球深处未脱气的储层。这是有争议的，因为大多数地幔对流模型假设俯冲板块渗透到下地幔，这很难与任何未脱气或“原始”地幔源的保存相协调。这项研究包括通过破碎、加热和捕获释放出的气体来测量加拉帕戈斯群岛海底玻璃中的重惰性气体（Ne、Ar和Xe）和CO2，然后用质谱法对它们进行分析。所得数据将有助于确定脱气对地幔中这些元素绝对丰度的影响，并可用于帮助约束地幔对流和分层的地球动力学模型。更广泛的影响：该项目支持伍兹霍尔海洋研究所的研究人员、技术人员和学生。它还通过加强超高真空萃取线和用于重惰性气体的质谱仪来支持机构基础设施。新的仪器将被开发和安装，它允许快速和同时测量重惰性气体，Ne， Ar和Xe。

ABSTRACT (0525864) KurzIntellectual Merit: This research will expand the number of heavy noble gas analyses (Ne, Ar, Xe) and CO2 in recently recovered submarine glasses from Fernandino volcano on the western flank of the Galapagos hotspot. These samples have unusual He isotope ratios, indicating that Fernandino volcano sits directly over the central melting zone of the hotspot. The noble gas isotopic ratios observed in Fernandino glasses are thought to originate from deep undegassed reservoirs in the earth. This is controversial because most mantle convection models assume that subducted slabs penetrate into the lower mantle, which is difficult to reconcile with the preservation of any undegassed or "primordial" mantle sources. This research involves the measurement of heavy noble gases (Ne, Ar, and Xe) and CO2 in Galapagos submarine glasses through crushing, heating and trapping of evolved gases and then their analysis by mass spectrometry. The resulting data will help determine the effects of degassing on absolute abundances of these elements in the mantle and can be used to help constrain geodynamic models of mantle convection and stratification. Broader impacts: This project supports researchers, technicians, and students at the Woods Hole Oceanographic Institution. It also supports institutional infrastructure by enhancing the ultra-high vacuum extraction line and mass spectrometer dedicated to heavy noble gases. New instrumentation will be developed and installed, which permits the rapid and simultaneous measurement of the heavy noble gases, Ne, Ar, and Xe.