As part of my 51 Pegasi b Fellowship, I am collecting spectra and analyzing other physical characteristics (grain size, mineralogy, vesicularity) of Earth rocks as a reference library for rocky exoplanet spectra. Below are slides from a recent lightning talk.
The enigmatic “red spots” on the Moon (so-called due to their high absorbance in the ultraviolet) are thought to be areas of silica-rich igneous material. But how silica-rich? What minerals and/or melts might be present? How do variables like water content and pressure of initial equilibration affect the assemblage and its mineralogical and spectral characteristics? … Continue reading MOON
Phase equilibrium experiments establish a depth and temperature for the magma chamber at Volcán Quizapu, Chile. Working in the experimental petrology lab of Julia Hammer at the University of Hawaii, along with field and petrological input from Quizapu expert Philipp Ruprecht, I used the capabilities of the cold-seal pressure line (CSPV) to simulate the magmatic … Continue reading ANDES
Dynamic cooling experiments on a synthetic martian lava reveal a history quite similar to that of pāhoehoe flows on Earth. Experimenting with the 1-atm gas-mixing furnace in the experimental petrology lab of the University of Hawaii, I re-created different cooling scenarios for this martian lava, which is based on the bulk composition of meteorite Yamato … Continue reading MARS
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., … Continue reading SUPERHEATING
The Fe-Ti oxides may not record shifts in magmatic conditions as quickly as we thought. A series of experiments on dacite magma with a large single-step reduction show that even after two weeks, titanomagnetite and hemoilmenite crystals display disequilibrium textures and compositions. Publication: First, E., Hammer, J. Re-equilibration of Fe-Ti oxides: Textural and … Continue reading FE-TI OXIDES
The rate of Mg diffusion in labradorite may be faster under typical arc magmatic conditions than indicated by dry experiments. In collaboration with Julia Hammer and Tom Shea, we discovered that Mg diffusivities display a wide range of values in labradorite, revealing anisotropy never … Continue reading MG DIFFUSION IN PLAGIOCLASE