Welcome! Among other pursuits, I am a geologist. I study modern and ancient mountain belts using field, analytical, and modelling work. My expertise is in hard-rock geochemistry, geochronology, and petrology, which I use to probe the history of Earth's lithosphere. For example: how does the chemical evolution of continental crust reflect planet-scale changes? Why and how do new subduction zones break? What is the composition of modern lower crust, and how does it keep continents stable over the long term?

One research direction I am most excited about is "geochemical signal processing": using statistical tools (PCA, ICA, cluster analysis) to isolate distinct trends from large geochemical datasets, including those I collect (e.g., by LA-ICPMS) or from compiled literature data (e.g., GEOROC). These types of analyses are applicable to a wide range of geologic data. I also use novel, high-resolution laser-ablation techniques to understand rock thermal and chemical histories from single crystals. Recently, I have combined these approaches with geophysical data to understand the composition and thermal state of cratonic mantle lithosphere.

I am currently an Assistant Research Professor at Penn State, which primarily involves running the "LionChron" LA-ICPMS laboratory and includes working closely with Drs. Jesse Reimink, Andy Smye, and Maureen Feineman. Pennsylvania has a rich natural and cultural history, and in my spare time, I investigate local geology, hikes, birds, and mushrooms.

Please feel free to reach out and discuss anything you see here at jmgarber [at] psu [dot] edu.