Our group studies the geochemical and climatic evolution of Earth using a combination of experimental and theoretical (modeling) approaches. His previous work has focused on measuring and modeling small variations in isotope ratios of a range of elements (e.g. 13C/12C, 18O/16O, 15N/14N, 26Mg/24Mg, 40ArATM) in marine sediments, pore-fluids, and ice cores. At Princeton, Higgins has set up a new analytical laboratory capable of state-of-the-art measurements of isotope ratios of Mg, Ca, Li, Sr, Si, and B in a range of natural samples. The Higgins group pursues questions ranging from the geochemistry of hydrothermal water-rock interactions and carbonate sediments to the processes that drive variations in atmospheric CO2 on million year timescales and regulate the oxygen content of Earth’s atmosphere and determine the chemistry of its oceans.