Nitrogen isotope data has also been used to measure the amount of exchange of air between the stratosphere and troposphere using data from the greenhouse gas Isotope | isotope | Isotope analysis | geochemistry | Kinetic isotope effect | Isotope separation | isotope geochemistry | Isotope effect | Geochemistry | Similar
Craig studied geology and chemistry at the University of Chicago, where he earned a Ph.D. under Nobel Laureate Harold Urey with a thesis on carbon isotope geochemistry in 1951.