Investigation of pre-Eruptive Volatile Contents of the TaupoIgnimbrite: Implications for Plainian-Ignimbrite Transitions

新西兰的陶波火山爆发（Taupo）。（186）A. 从普理安岩到熔结凝灰岩转变的壮观例子 喷发活动 这种变化可能是由于 减少熔体中的挥发物含量， 火山爆发时的大小 岩浆中的挥发物 其产生了前体普宁火山岩是众所周知的。 这 项目将确定挥发分含量和挥发 通过分析熔结凝灰岩产生的岩浆内的分布 斑晶中的熔融包裹体，以评估 易挥发成分的变化。 计划利用离子和电子探针技术， 在整个过程中测定熔融包裹体中的H2O、f和Cl 熔结凝灰岩 主要元素的电子探针分析将 帮助评估夹杂物是否发生了变化。 最后， 不同地层块状岩石微量元素分析 层位将显示挥发性和微量元素是否耦合， 在这个岩浆系统中分离。

The Taupo eruption of New Zealand (ca. A.D. 186) contains a spectacular example of transition from plinian to ignimbrite eruptive activity. This change is probably due to a combination of decrease in volatile content of the melt and increase in vent size at the time of eruption. The volatile content of the magma which produced the precursor plinian tephras is well known. This project will determine the volatile content and volatile distribution within the ignimbrite-producing magma by analyzing melt inclusions in phenocrysts, in order to assess the influence of the volatile component in a plinian-ignimbrite transition. Using ion and electron microprobe techniques it is planned to determine H2O, f, and Cl in melt inclusions throughout the ignimbrite. Electron microprobe analyses of major elements will help assess if inclusions have undergone alteration. Finally, trace element analyses of bulk rock from different stratigraphic horizons will show if volatile and trace elements were coupled or decoupled in this magmatic system.