My research seeks to address questions related to...
- Understanding global climate dynamics and Earth-system processes,
- Reconstructing the physical and environmental conditions of modern and ancient oceans, ecosystems, and atmospheres, and
- Evaluating organismal-environmental interactions on the individual and ecosystem level.
Development and Application of Terrestrial Climate and Environmental Proxies
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Normal-alkanes are a major component of terrestrial higher plant leaf-waxes and their isotope ratios reflect physiological and environmental parameters. They are also highly refractory, and readily preserved in geologic sediments. As a result, they are an ideal class of compounds to explore ancient terrestrial ecosystem dynamics and paleoclimates. |
Carbon and Hydrologic Cycles during Past Climates
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Ancient carbon and water cycles are investigated through the examination of the organic materials preserved in geological archives. These records are used to elucidate the mechanisms driving hydroclimate variation associated with climate perturbations and to increase our appreciation of the coupling and feedbacks between these cycles. |
Terrestrial Biologic Responses to Past Climates and Climatic Events
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The relationships between terrestrial ecosystems and climatic states are studied using organic compounds preserved in the sediment record. Research in this area focuses on multiple intervals in Earth history (e.g., near-modern, Holocene, Neogene, Paleogene) and within multiple sedimentary settings (e.g., soils, lakes, marine) to assess the terrestrial ecosystem’s response to climate. |
Forensic Applications of Stable Isotopes
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This work is focused on developing and applying isotopic technique to determine the geographic origin of materials. The scope of this research is broad and utilizes a variety different organic and inorganic phases and different isotope systems. A major recent emphasis under this theme has been the development and translation of these methods to human systems and environments. |
Social and Environmental Geochemistry
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The spatiotemporal patterns of isotope ratios are analyzed and plotted using geographical information system (GIS) software to reveal the underlying processes that govern isotope variation across space and time. These isotopic landscapes, also known as isoscapes, have great utility to elucidate, quantify, and model fundamental processes shaping isotope ratios of natural and produced materials. In this area, my recent focus has been on understanding the linkages between climate, hydrology, geology, economics, and society.
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