I am a field geologist interested in the evolution of Earth's surficial environments and biosphere. My research addresses the chemical development of the early oceans and atmosphere, the environmental context of early animal evolution, and the geologic factors that regulate sedimentary basins. In my studies, I try to create the basic geologic framework for sedimentary basins and orogenic belts in northwest Canada, northern Siberia, southern Africa, and the western United States. These field mapping studies are the starting point for more topical laboratory-based studies involving geochemical, paleontological, and geochronological techniques. Because Mars and Earth are thought to have had similar early climates and geologic conditions, my work on the early Earth may help guide the analysis of early environments on Mars.