Our tool of choice, the isotope ratio mass spectrometer (right), hooked up to a home-built, computer-controlled sample preparation system for gases (left and center)

Our tool of choice, the isotope ratio mass spectrometer (right), hooked up to a home-built, computer-controlled sample preparation system for gases (left and center)

What excites us


Isotopic ordering a.k.a. "clumping"

Justin operating the laser-fluorination line (Cin-Ty looking on) to extract oxygen from minerals for isotopic analysis. Justin uses the oxygen to learn about ancient environments.

Justin operating the laser-fluorination line (Cin-Ty looking on) to extract oxygen from minerals for isotopic analysis. Justin uses the oxygen to learn about ancient environments.

The extent to which rare isotopes are bound together (or, rather, "clumped") in nature tells us a great deal about how natural materials were formed. While much of the work in the past decade has focused on determining mineral formation temperatures, we are finding that formation pathways can also be recorded. We are using isotopic ordering in O2 and other small molecules as tracers of these processes in nature. We also hope to understand more generally how isotopic "clumps" behave when not at equilibrium so we have a framework in which to interpret their natural variations.

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Atmospheric chemistry and physics

Simulating upper-atmospheric chemistry to determine its effects on isotopic composition.

Simulating upper-atmospheric chemistry to determine its effects on isotopic composition.

Atmospheric chemistry manifests itself on the global scale through the general circulation. Air is transported between continents and into the upper atmosphere; it moves from hot to cold regions and back again; it undergoes vigorous photochemistry in one place but not another. The resulting imprint is complex, and many of the species involved are not preserved in records of ancient air. Consequently, there is little information about how the atmosphere as a whole evolved through time. We are using isotopic ordering in ice cores to trace atmospheric chemistry and general circulation on decadal to millennial timescales. We also have an interest in the long-term evolution of the atmosphere in deep time.

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Biogeochemical cycling

Huanting sampling seawater so she can analyze the isotopic variants of the dissolved gases. They tell us about how life (mostly microbes) use their nutrients, as well as how other aspects of the ocean can affect that.

Huanting sampling seawater so she can analyze the isotopic variants of the dissolved gases. They tell us about how life (mostly microbes) use their nutrients, as well as how other aspects of the ocean can affect that.

On a global scale, the relationship between the climate and the biosphere is still poorly known for timescales longer than a century. We want to understand this relationship, and in particular, the biosphere’s response to climate change and human activity. We are therefore working to characterize the mechanisms that govern biogeochemical cycles, and the evolution of those cycles through time. Our current projects involve laboratory and field studies of biological activity in the ocean, and we are developing tools to understand biological nutrient cycling on land.

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Tools of the trade