Campanian Ignimbrite volcanism and the final decline of the Neanderthals

The eruption of the Campanian Ignimbrite 40,000 years ago coincided approximately with the final decline of the Neanderthals and a technological and cultural transition from the Middle to Upper Paleolithic. I use three-dimensional models of aerosol microphysics and climate to predict the distribution of environmental stresses generated by the eruption and compare the results to archaeologic and ice core records.

Siberian flood volcanism and the end-Permian mass extinction

The Siberian Traps are one of the largest known continental flood basalts, and have been invoked as a trigger for the catastrophic end-Permian mass extinction. Understanding the environmental consequences of volcanism requires quantitative constraints on volatile degassing, the extent of explosive volcanism, and the climatic effects of volcanic emissions in the atmosphere. I approach these problems through a combination of field, laboratory, and modeling techniques.

Volcanism and climate on Mars

How has Mars sustained volcanism throughout its 4.5 billion year history? How has that volcanism modulated Martian climate? Simple one-dimensional models illuminate the coupled magmatic-climatic evolution of Mars.

Ash dispersal from modern and ancient eruptions

Ash represents one of the primary records of ancient explosive eruptions, and one of the primary hazards of modern eruptions. How can models of ash dispersal help us to interpret ancient ash deposits on Earth--and perhaps even on Mars?

Erosion on Titan

Titan, Saturn's largest moon, has a dominantly water ice crust and a methane-rich atmosphere. Methane precipitation and runoff appear to have carved river networks on Titan much like those on Earth. I use theoretical predictions of the evolution of drainage networks and measurements of the shapes of drainages on Titan in order to estimate the erosional history of Titan's surface.