Eric D KellyPostdoctoral Fellow, Jackson School of Geosciences
Eric is a petrologist and geochemist interested in thermodynamic and kinetic problems from lower crustal to atmospheric environments. Most of his research is fundamental to the mechanisms and processes governing chemical reactions in geological systems used to investigate tectonic history. Data collection and analysis typically includes mapping and sample collection, petrography, electron-beam techniques (e.g., electron microprobe analysis), mass spectrometry (e.g., laser-ablation ICPMS), and numerical modeling.
Lower and Middle Crust:
During metamorphism, slow kinetics lead to thermal overstepping of reactions and short length-scales of chemical equilibration among phases, causing disequilibrium and potentially erroneous interpretations of metamorphic conditions. Evidence of these effects are commonly hidden in the textural features of rocks and must be revealed using sophisticated techniques like high-resolution X-ray computed tomography and spatial statistical analysis. Eric has quantified these effects in a wide range of metamorphic rocks and is working toward incorporating estimates of disequilibrium effects into models of crystallization to more accurately describe metamorphic conditions in the lower and middle crust.
Improved estimates of departures from equilibrium will expand our understanding of crystallization in a wider range of metamorphic systems. Toward this effort, Eric is improving application of Classical Nucleation Theory to metamorphic rocks and determining rates of intergranular and intracrystalline diffusion in these systems.
Slow kinetics also enhance our ability to determine tectonic history. Preserved chemical zoning in crystals can be exploited to quantify changes in pressure and temperature and even rates of heating and cooling during prograde and retrograde metamorphism. Combining textural analysis, crystal chemical zoning, thermodynamics, numerical simulations of crystallization, geochronology, and thermochronology, Eric produces P-T-t-D paths used to interpret lower and middle crustal processes and reconstructions of tectonic history.
Eric is also interested in thermodynamic and kinetic controls on porosity and permeability in sedimentary rocks. Fluid chemistry and substrate characteristics can enhance or retard nucleation and growth of pore-filling crystals in hydrocarbon reservoir materials. The controls on methane bubble nucleation and growth during diagenesis are also poorly understood but dependent on kinetic limitations to thermodynamic transformation.
Other pursuits include prediction and modeling of nucleation and precipitation (e.g., H2O-ice and water) in the atmosphere and investigation of mineral aerosols that affect atmospheric nucleation and precipitation.
Areas of Expertise
Structural, microtextural, and chemical investigations of metamorphism using field, analytical, and numerical techniques: Petrogenesis of metamorphic rocks including pressure-temperature-time-deformation paths that reveal crustal processes; thermodynamic and kinetic investigations of nucleation and diffusion, including impacts of slow kinetics on metamorphic crystallization that cause disequilibrium.
Good rocks, bad assumptions! Unrecognized limitations to equilibrium models in metamorphic petrology, Bates College, Lewiston, ME (2014)
Disequilibrium during regional metamorphism: challenges to interpretations of metamorphism, Boston University, Boston, MA (2013)
Abandoning the equilibrium assumption: Effects of disequilibrium on metamorphic interpretations, Baylor University, Waco, Texas (2012)
Implications of garnet resorption for the Lu-Hf garnet geochronometer: An example from the contact aureole of the Makhavinekh Lake Pluton, Labrador, Colby College, Waterville, Maine (2011)