SUPERHEATING

Heating a rock above its liquidus temperature has significant effects on the morphology and composition of crystals formed upon cooling.

 

 

Working with Julia Hammer and Tanis Leonhardi (former undergrad in the lab, now PhD candidate at Berkeley), we explored the effects of superheating on a silica-undersaturated rock with olivine on the liquidus. Based on previous work (e.g., Colin Donaldson’s papers) we expected to see morphological differences with different degrees and durations of superheating, but quantification of these differences, via the surface area per unit volume of the olivine crystals, had not yet been applied to other superheating experiments. Another exciting development was the discovery of minor-element (Ni, Ca) compositional changes in olivine that correlate with superheating magnitude.

TtLdNiO

Relationships between superheating magnitude (y axis), crystal morphology (SvP), and NiO partition coefficients.

Publication: First, E., Leonhardi, T., Hammer, J. (2018) Effects of superheating magnitude on olivine composition and growth morphology. Contributions to Mineralogy and Petrology, in review.