MAGMA PLUMBING SYSTEM BENEATH HERÐUBREIÐ, NORTHERN RIFT ZONE, ICELAND

Iceland is the most volcanically diverse location on the planet as nearly every type of volcano can be found on this island. Volcanoes are an existential and powerful threat to the modern world on both short and long time scales, and understanding their inner workings is paramount to protecting society from one of nature’s deadliest and most destructive activities. Given that gathering and analyzing information about every type of volcanic activity on Iceland is a daunting task, this study focuses on a specific locality in Iceland’s Northern Volcanic Zone, the volcano known as Herðubreið (Herdubreid). The purpose of this research was to determine the depth of crustal magma bodies that feed Herðubreið. The methods of this project involved using the analyzed weight percent of major oxides in samples of glass collected from the volcano over the last few years to calculate the pressure at which the magmas partially crystalized. From this pressure we established the relative depth of the magma chamber or chambers located in the underlying crust. The results reveal the presence of two main magma bodies located at 11 and 17 km below the surface. These depths were expected as they agree with the results of seismic studies for this area and are consistent with results obtained using identical petrologic methods for other volcanic plumbing systems in Iceland. This work provides part of the bigger picture of Icelandic volcanism, as Herðubreið is only one of about thirty active volcanoes on Iceland. However, while the results of this work constitute a necessary first step for improving warning systems and updating evacuation procedures for people who live or work near similar types of volcanoes, more work is needed to gain a complete picture of the magma plumbing systems in the crust beneath Iceland. Additional research is underway to collect and study samples from these volcanic systems with the objective of understanding how these different types of volcanoes work, how the different plumbing systems interact with each other, and how to place the results obtained for Iceland into a global context.