Continental and Convergent-Margin Volcanism: Isotopic Studies of Fluids and Rocks

这笔拨款将继续支持对稀有气体和其他稀有气体同位素的研究，这些气体来自火山中心的热点，以及趋同的板块边缘和大陆裂谷。主要的重点是3He作为地幔挥发物的“原始”示踪剂，以及它与甲烷和CH4和CO2中碳的同位素组成的关系。3He在火山熔岩中的宇宙成因性质已被认识到，它在侵蚀研究中作为示踪剂的用途已被证明。与洋中脊玄武岩相比，在8个太平洋热点地区发现了较高的3He/4He比率，这清楚地证明了气体通过上升的羽流从较少枯竭的地幔中输送。这些以及类似类型的利用稀有气体解决地幔化学和动力学问题的研究将在PIs的监督下继续进行。这笔资金将用于对已经收集的许多样品进行分析，并将支持PI实验室再运行一年

This grant will provide continued support of research on rare gasses, and isotopes of other rare gasses, from volcanic centers over hot spots, and along convergent plate margins and continental rifts. Primary emphasis has been on 3He as a "primordial" tracer for mantle volatiles, and its association with methane and the isotopic composition of carbon in CH4 and CO2. The cosmogenic nature of 3He in volcanic lavas has been recognized and its usefulness as a tracer in erosion studies has been demonstrated. High 3He/4He ratios, relative to Mid-Ocean Ridge Basalts, have been identified in eight Pacific hotspot terrains, clear evidence of transport of gases from the less depleted mantle by rising plumes. These and similar types of research using rare gasses to solve problems of mantle chemistry and dynamics will continue under the PIs supervision. This award will provide for the analysis of many samples already collected, and will support the operation of the PI's lab for another year