Earth Scientist interested in the early history of life and the co-evolution of Earth and life. Particular interests are in the application of advanced analytical techniques to major questions in microbial palaeontology, biogeochemistry, early surface environments and ecosystems, the search for life on Mars, and Mars Sample Return. I am interested in the development and application of novel approaches to criteria for determining the biogenicity and metabolic affinities of Precambrian fossils.