Creaser’s research in the Earth Sciences is focused on isotope geochemistry and geochronology, but is applied to topics as diverse as Earth’s history of oxygen evolution and biotic evolution, sedimentary basin evolution and geological timescale calibration, and crustal fluid flow and ore deposit origins. His research in the geochronology of sulfide minerals has been directed at developing, testing and applying the Re-Os system to a wide range of minerals in varied ore deposit settings, in order to directly constrain the timing of ore deposition and hydrothermal fluid flow.