My research lab is driven by several fundamental questions:

• What processes, either physical or chemical, initiate regolith formation by rock weathering, and how do these processes interact to set the depth and structure of the critical zone?
• How do modern and historic variations in climate affect the distribution of weathering products (e.g., talus, soil, ground and surface water solutes) in the landscape?
• How do tectonic processes affect the generation of nutrients in terrestrial landscapes by regulating the supply of minerals available for weathering and soil production?
• How do human activities impact the sustainability of soil and groundwater resources?

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Active Projects

Tectonic controls on chemical erosion in Northern California

Variable uplift rates across the Mendocino Triple Junction provide an ideal natural laboratory to test the influence of mineral supply rates on the balance between physical and chemical weathering in mountainous landscapes. To this end, along with collaborators from University of Wisconsin, I am combining measurements of bulk regolith and bedrock geochemistry with cosmogenically produced radioisotopes to understand the balance between weathering and erosion.

Climatic controls on evolution of the Central Appalachians

Landscapes respond to climate perturbations over geologic time. Evidence of Pleistocene glaciations exists throughout the Appalachian Mountains. Together with collaborators from Oregon State University and University of Vermont, we are working to understand how we can “read” the landscape to infer information about the evolution of the Appalachians.

Chemo-mechanical fracturing in the deep critical zone

Regolith formation and deep critical zone evolution respond to the dynamic feedbacks between physical and chemical processes occurring in the subsurface. Primary among these processes are fracture propagation in bedrock and dissolution of bedrock minerals. My collaborators and I combine field, lab, and modeling studies to understand the complexities of these processes.

Structural controls on chemical and physical erosion in Costa Rica

Subducting seamounts under the Nicoya Peninsula of Costa Rica are thought to drive geologically recent and highly variable uplift rates across a small and rapidly weathering system. Along with collaborators at UC-Santa Barbara, I am working to test the relationships between chemical and physical erosion in a tropical environment, where climatic and lithologic conditions conspire to drive rapid bedrock weathering rates.