Postdoctoral Associate Jonathan O’Neil arrived at DTM following the receipt of his Ph.D. in geochemistry at McGill University. His research interests focus on the early evolution of the Earth. He is interested in the crust-mantle system, and he studies the Lu-Hf, Re-Os, and Nd-Sm radiogenic isotopic systems including the short-lived 142Nd  isotopic tracer to determine the timing and extent of early differentiation.  Most of O’Neil’s work is concentrated on the 4.28-billion-year-old Nuvvuagittuq greenstone belt located in the Northeastern Superior Province, Quebec, Canada. He makes use of geochronology, petrology, and geochemistry to constrain the geological history of this Hadean terrain and the composition of Earth’s early crust.