Rensselaer Polytechnic Institute’s Frank Spear, Ph.D., professor of earth and environmental sciences and Edward Hamilton Distinguished Educator Chair, is the 2024 recipient of the Walter H. Bucher Medal from the American Geophysical Union (AGU). The medal is presented annually to a “senior scientist in recognition of original contributions to the basic knowledge of crust and lithosphere.” It is considered a recognition of lifetime achievement.

“I am both extremely honored and more than a bit humbled to receive the Bucher Medal from the AGU, especially considering the past recipients,” said Spear. “I feel most fortunate that my career in science and education has enabled me to pursue pretty much any scientific directions that I found interesting. My work has enabled me to travel to some extraordinary places to do fieldwork and to work with some fantastic colleagues and students. It is especially rewarding that the AGU has considered my contributions to be worthy of this recognition.”

Spear’s research focuses on two major directions in metamorphic geochemistry: crustal evolution and the thermodynamic modeling of metamorphic processes.

For 30 years, Spear’s research group has developed new techniques for the interpretation of metamorphic petrogenesis, or how metamorphic rock forms. Their studies involve modeling mineral reactions, textures, and chemical zonation in both major and accessory phases. The goal is to construct pressure-temperature-deformation-time histories that can be used to interpret the tectonic evolution of a terrane. Spear and team have applied these techniques to areas in the Alps, New England, southern Chile, the Mojave Desert, British Columbia, the Adirondacks of New York, and the Cyclades Blueschist Belt of Greece. Current field projects are underway in Central New England, the Ruby-Humboldt range of eastern Nevada, Adirondack Mountains of New York, and the Cyclades Blueschist Belt in Greece. Much of their current work utilizes inclusion barometry, especially quartz in garnet or QuiG, to constrain the pressure and temperature conditions of garnet nucleation and growth.

Spear also specializes in the development of software to analyze and model metamorphic processes. These efforts include calculation of pressure and temperature conditions using thermobarometry, plotting of metamorphic phase diagrams, calculation of metamorphic phase equilibria such as petrogenetic grids, isochemical phase diagrams, and models of chemical zoning, application of diffusion theory to constrain metamorphic time scales, and thermal modeling of metamorphic evolution in thrust belts and subduction zones.

Spear earned his bachelor’s degree from Amherst College and his Ph.D. from University of California, Los Angeles. His honors over the years have included fellowships with the Mineralogical Society of America, the Geological Society of America, and the AGU. He is a past recipient of the N.L. Bowen Award, the Dana Medal of the Mineralogical Society of America,  and the Murchison Medal and the Barrow Award from the Geological Society of London. 

Spear will be presented the engraved medal at AGU’s annual meeting in December.