Abstract

Melt inclusions from 25 eruptions of Kilauea Volcano over the last 600 years highlight the important processes of fractionation, mixing and degassing prior to eruption. The sampled eruptions span a large range of styles, ranging from effusive through to transient explosive and fountaining. The data show that there is a statistical difference in the geochemistry between the different styles, and through different time periods at Kilauea, suggesting that the explosivity of melts might be “set” right from the point of separation from the mantle source. We look at one fountaining eruption in detail (the 1959 Kilauea Iki eruption) to investigate how fountains are triggered. Inputs of hot, primitive, gas-rich melts mix with cooler, stored melts, causing rapid vesiculation, leading to fountains. Along the way, we see how melt inclusions are dramatically altered by processes such as post-entrapment crystallization and the development of a shrinkage bubble, illustrating some of the pitfalls of melt inclusion work.