Origin of Anomalous Sulfur in Volcanic Eruptions: A Study Utilizing the SHRIMP Ion Microprobe

提出了硫同位素的微观研究方法 硫化物和硬石膏晶体的变异性 最近富SO2火山喷发的喷发产物（El 希雄山Pinatubo）。 硬石膏现在 被认为是火山喷发产物中的一个重要阶段， 许多富含二氧化硫的岩浆，但问题仍然存在， 硬石膏的幼年与捕虏晶性质 以及SO2从熔体中释放的机理。 的 这些问题的答案需要硫的数据 硬石膏和硫化物晶体的同位素组成 喷发产物。 SHRIMP是一个理想的工具， 解决这些问题。 初步的SHRIMP结果排除了 全硬石膏形成于单期岩浆 结晶过程 SHRIMP将用于评估 硬石膏是否通常是混合来源于这些 爆发。 这项研究将有助于限制喷发前的岩浆 S化学和脱气行为，以及解决 是否偶然地重新激活了先前存在的 外来硫是过去的关键组分， 现在的火山喷发注入了大量的 大量改变气候的二氧化硫进入大气。

A study is proposed of the microscopic sulfur isotopic variability of sulfide and anhydrite crystals in the eruption products of recent SO2-rich volcanic eruptions (El Chichon, Nevado del Ruiz, Mt. Pinatubo). Anhydrite is now recognized as an important phase in the eruption products of many SO2-rich silicic magmas, but questions still remain about the juvenile vs. xenocrystic nature of the anhydrite and the mechanism of SO2 release from the melt. The answers to these questions require data on the sulfur isotopic composition of anhydrite and sulfide crystals in the eruption products. The SHRIMP is an ideal tool to apply to these problems. Preliminary SHRIMP results rule out formation of all anhydrite in a single-stage magmatic crystallization process. The SHRIMP will be used to assess whether anhydrite is generally of mixed origins in these eruptions. The study will help constrain pre-eruptive magma S chemistry and degassing behavior, as well as resolve whether fortuitous remobilization of pre-existing extraneous sulfur is a critical component of past and present volcanic eruptions which injected significant amounts of climate-altering SO2 into the atmosphere.