MARGINS Post-doctoral fellowship - Jeremy Boyce: Exploring the Record of Magmatic Volatiles in a Volcanic Arc via H, C, F, S, and Cl in Apatite

摘要测定岩浆挥发物的一种尚未开发的方法是测定含挥发物的火成岩矿物的化学性质。具体来说，磷灰石(名义上是Ca5（PO4)3(OH，F,Cl)）包含关键元素H， C， F，Cl和S，以前被用来限制古岩浆中Cl， F和S的浓度。在这笔资金的支持下，pi建议开发和应用二次离子质谱仪（SIMS，或离子微探针）来测量哥斯达黎加弧喷出岩石中磷灰石中挥发性元素浓度的变化（与REE和其他微量元素一起），在过去的60Ma中，已知物质的类型被俯冲。SIMS结合了定量测量上述所有元素的能力，具有无与伦比的空间分辨率（深度剖面模式为1um，点分析模式为2um）。晶内挥发物的分带可能代表一个特定岩浆体的演化，而磷灰石挥发物在整个特定火山环境历史中的变化可能表明来源的变化，这是边缘项目的重要目标。更广泛的影响包括博伊斯是博士后，将探索一项新技术，将创建一个博物馆展览，以及将执行SIMS的工作，帮助SIMS社区基础设施。

AbstractAn underexploited tool for determining magmatic volatiles lies in measuring the chemistry of volatile-bearing igneous minerals. Specifically, apatite (nominally Ca5(PO4)3(OH,F,Cl)) incorporates the key elements H, C, F, Cl, and S and has previously been used to constrain Cl, F, and S concentrations in ancient magmas. Under this funding, the PIs propose to develop and apply the secondary ion mass spectrometer (SIMS, or ion microprobe) to measure variations in volatile element concentrations (in conjunction with REE and other trace elements) in apatites from extrusive rocks from the Costa Rica arc, where the type of material being subducted has been known to change over the past 60Ma. SIMS combines the ability to quantitatively measure all of the above-mentioned elements with unmatched spatial resolution (1um in depth profiling mode, 2um in point analysis mode). Intracrystalline zoning of volatiles may represent the evolution of one particular magma body while variations in apatite volatiles throughout the history of a particular volcanic setting may indicate changes in the source, important goals of the MARGINS program.Broader impacts include the fact that Boyce is a post-doc, that a new technique will be explored, that a museum exhibit will be created, and that SIMS work will be performed, helping with SIMS community infrastructure.