I am fascinated by the nature of volatiles in magmatic and volcanic systems. This interest is linked to a range of topics including melt generation, magma transport and differentiation, and eruptive dynamics. My primary resource for exploring these fields is melt inclusions. These accidents of imperfect crystal growth provide us with the only means for directly examining pre-eruptive volatile content of magma. Furthermore, they form during various stages of magma ascent and differentiation, providing snapshots of the changing physicochemical conditions of a magma prior to its eruption. Reaching an understanding of the variation of volatiles, which is coupled to elemental and isotopic variations, in melt inclusions gives insight into dynamic processes that govern the behavior of magma before and during volcanic eruption. Recently, I have also gained an interest in the study of nominally anhydrous minerals. Such minerals can act as hygrometers, allowing for further understanding of the distribution of water in magmas.
Since my recent arrival at Columbia as a PhD student, I have begun researching magmas from several volcanoes in the Aleutian arc. I am interested in determining the characteristics of magma entering the crust and the growth and eruption of crustal reservoirs. The former objective can be approached by studying primitive melt inclusions. Essential to pursuing the latter is understanding volatile content of melt inclusions and minerals (e.g., clinopyroxene). The pressure (or depth) of magmatic differentiation can be traced using magmatic volatile content because volatile solubility is controlled by pressure. The timescales of crustal residence and ascent of magmas limit the diffusion of chemical species through minerals and melt. Using models for volatile saturation and diffusion, I will explore the spatial-temporal histories of magma transiting the crust.
My master's research was on the evolution of alkalic magmas at Ross Island, Antarctica. I studied melt inclusions from four volcanic centers on the island. The inclusions record extremely CO2-rich (>0.9 wt.%) magmatism and span a full range of compositions from primitive basanite to phonolite. Thus, they store a record of melt composition during ascent from near-Moho depths and differentiation from near-primary compositions. The primary goal of the study was to determine the controls on the volatile contents of pre-eruptive magmas, which also involved exploring magma ascent, differentiation, and storage. I found that diffusive reequilibration of H+ plays an important role in H2O and CO2 recorded in some melt inclusions, while others require a more complex history involving magma mixing to explain H2O and CO2 variations.
As an undergraduate at University of Oregon, I investigated magma generation processes by evaluating volatile and major element compositions of primitive arc magmas erupted at cinder cones in the Lassen Region of the Cascade volcanic arc. This is a particularly interesting arc to study magma generation because it is a near global end-member in hot slab subduction, which has led several investigators to question the importance of slab-derived fluids in generating magmas at this arc. I studied basaltic melt inclusions representing calc-alkaline and low-K tholeiitic magma types, which have been suggested to represent melt generation by fluid-fluxing and dry-decompressing, respectively. I found that the studied calc-alkaline basalt contains the signature of slab-derived fluid, but the origin of the low-K tholeiitic magma is a bit more ambiguous.
A set of beautiful olivine-hosted melt inclusions. Those outlined in yellow are doubly-intersected.
A doubly-intersected plagioclase-hosted melt inclusion, my first and only!
FTIR at University of Oregon (picture shamelessly borrowed from Paul Wallace's website - but I did take the picture!)
Here is everyone's favorite inclusion plot. This one is from my undergraduate thesis.