Microstructural controls on the physical and chemical processes which occur during solidification of magma.
Research Area
I am interested in the processes which occur during magma solidification, such as convection and the physical behaviour of crystal mushes. I use the microstructures preserved in fully solidified rocks to work out the details of the solidification history: this can be thought of as an inverse approach to that of materials scientists, who carefully control the solidification conditions to ensure the microstructure in the finished product results in the required physical properties of the material.
My research is mainly focussed on mafic systems such as layered intrusions, with a particular interest in the physical and chemical complexities involved in systems in which the liquid splits into two immiscible liquids. I also have an interest in more silicic magmas, as well as the solid-state processes that occur in metamorphic rocks.
Project Interests
I am interested in developing experimental studies to explore the physical behaviour of magma bodies in which the liquid has unmixed into two silicate liquids (one Fe-rich and the other Si-rich). The two liquids have different affinities for the various mineral phases on the liquidus, leading to changes in crystal settling velocities in the bulk magma once it has split to form an emulsion, and complex changes in the physical behaviour of crystal mush developing on the margin of magma bodies, such as the rate of liquid percolation and compaction. The results of such experimental studies can be used to decode the microstructural and geochemical record in natural examples known to have undergone such liquid unmixing during fractionation, such as the Skaergaard Intrusion of East Greenland, and will help in developing our understanding of the formation of economically important concentrations of PGEs and other metals.
