My research interests cover the entire range of Earth’s geologic history. I have proposed a model for Earth’s early surface environment and atmosphere that contrasts sharply with the currently accepted view, but which resolves several unanswered questions concerning the Earth’s (and Mars’) early climate, the origin of life, and the transition to an oxygen-rich atmosphere. I have studied the trace element geochemistry of minute phenocrysts in altered volcanic ash layers as a means of distinguishing layers from one another and correlating them over large distances. My work on the groundwater hydrogeology (and especially karst hydrology) of the Town of Wright in New York provided the town with information for use in planning. I am currently working on three additional projects: characterization of newly discovered mantle xenoliths from a locality in eastern Australia, a numerical model simulating the development of drainage networks (including stream capture), and a potentially practical method for the capture of carbon dioxide from Earth’s atmosphere.