Participating Faculty, UW Astrobiology Program
Fax: 206-543-0489 (shared)
Interests: Precambrian Life and Environments, Astrobiology
Research Groups: Isotope Geochemistry, Astrobiology, Paleontology, Geomicrobiology, Sedimentology/Stratigraphy/Sedimentary Petrology
I am interested in the origin and earliest evolution of life on Earth and how that can be used as an analogue for life elsewhere in the Universe. My research techniques lie at the intersection of geology, biology and chemistry, examining the oldest and best-preserved rocks available. This involves fieldwork in the Australian outback, on the Greenland ice-cap and in the Canadian woods, amongst other places.
Examples of current projects include:
Early evolution of bacterialmetabolism - palaeontology and stable-isotope geochemistry of Archaean sedimentary rocks, with the aim of determining when the main forms of microbial metabolism first arose and whether this caused environmental change in the atmosphere and oceans.
Early Archaean atmospheric composition - detrital heavy minerals in Archaean fluvial sandstones, with the aim of determining whether their alteration patterns indicate primordial atmospheric greenhouse effect modulated by carbon dioxide or some other gas in order to counteract the weaker solar luminosity during Earth's early history.
Secular trends in marine nutrient fluxes and their ecological impact - phosphorus and nitrogen geochemistry in sedimentary rocks through time, with the aim of betterquantifying oceanic fluxes and budgets for these elements, identifying temporal trends in their sources and sinks, and determining whether these reflect or influenced ecosystem evolution.
Early evolution of continental crust - trace-element and radiogenic-isotope geochemistry of basalts ~3.5 billion years old across an ancient unconformity in the PilbaraCraton, Australia, with the aim of contraining the primordial growth rate of continental crust, the tectonic environments of the early Earth and the biological impacts of crustal differentiation.
Molecular fossils from early Precambrian rocks - organic geochemistry of well-preserved Archaean and Palaeoproterozoic hydrocarbons and kerogen, with the aim of discovering organic geochemical biomarkers that constrain the phylogenetic history of microbial ecosystems.