Petrology: Igneous, Metamorphic and Volcanic Studies
Department of Earth Sciences
University of Cambridge
2009 - 2013: MSci Earth Sciences, University of Cambridge
2013 - Present: PhD Student, 'Petrological constraints on the structure of Icelandic volcanic systems', University of Cambridge
My research is focussed on using igneous petrology to place constraints on the structure of Icelandic volcanic systems (i.e. magma storage depths and mineral crystallisation pressures). Iceland is an excellent natural laboratory for investigating igneous processes due to the presence of both mid-ocean ridge and mantle plume magmatism at one setting.
Melt heterogeneity in Iceland has long been observed between melts of different volcanic systems, and within single eruptions through the entrapment of melt within crystallising phases. Kistufell (Northern Volcanic Zone) and Midfell (Western Volcanic Zone) are both picritic eruptions in Iceland that have been the focus of many studies in the past, measuring major and trace elements, and isotopes. I have measured major, trace and volatile elements in olivine-hosted melt inclusions from pillow glasses collected at these localities to look into the volatile signature of melts entering these two volcanic systems. Olivine is the first phase to crystallise from melts entering the system, so highly forsteritic olivine has the potential to trap melts low in the crustal system before the diversity of melts is lost by mixing and crystallisation at shallower depths in the crust. We hope to be able to better constrain the volatile characteristics of the mantle beneath Iceland by looking at these melt inclusions.
In collaboration with Dr Glenn Gaetani at Wood's Hole Oceanographic Institution, I have conducted some melting-crystallisation experiments on Icelandic basaltic glass using a piston cylinder apparatus and a gas-mixing furnace. The aim of this part of the project is to gain more insight into the role pressure has on controlling the crystallisation and composition of igneous phases. We have conducted experiments at a range of pressures and temperatures covering conditions in the Icelandic crust in order to predict liquidus-phase relationships for our bulk basaltic glass composition (Midfell, Western Volcanic Zone, Iceland). Using the compositions of our experimental phases we hope to be able to test how well existing igneous liquid barometers can reproduce the known pressures of our experiments.
Supervisors: Dr John Maclennan and Dr Glenn Gaetani