Our research group applies continuum mechanics to understanding the interaction of the earth and atmosphere at many different time scales. We link individuals with research interests ranging from short term climatic variation to mantle:crust interaction. We have been investigating the influence of atmospheric processes on the development of mountain ranges from the scales of the entire mountain range to that of single large river catchments like that of the Indus or the Tsangpo. We employ geodetic, seismic, geomorphic, and petrological techniques to develop an integrated image of a developing mountain system. To produce some understanding of the behavior of the deeper parts of the earth, often not exposed during the active phase of mountain building, we work closely with petrologists and structural geologists looking at the exposed roots of the mountains. The image assembled from these observations then provides many of the constraints for constructing a comprehensive numerical model that allows us to examine the dynamics of the mountain building processes across many scales.
The analog modeling lab in the Department of Earth Sciences has been designed as a resource for teaching and research. Analog modeling can give us qualitative and quantitative insights into boundary conditions and material behavior. The experiments allow us to investigate the individual effects of different parameters or geological processes. Analog materials are weak enough to deform rapidly under laboratory conditions and they have rheologies which are scalable to Earth systems. Several analog materials and model approaches exist. Brittle behavior in rocks is modeled by granular materials (such as sand), which deforms in a way described by a pressure-dependent, elastic-plastic constitutive relationship. The viscous behavior of rocks is simulated by viscous materials such as silicone putty, honey and glucose syrup. The rheology of these materials is commonly temperature dependent and can be described by a power law constitutive relationship. Plastic material, such as plasticine and wax are also used to model rock deformation. Please go to the Projects link above to see examples of how we are using this facility in research and teaching.
Microstructures and microstructural processes profoundly influence the rheological evolution of Earth’s lithosphere. Our research group seeks to better understand microscale physical and chemical processes, and the interrelations between microstructural and mechanical evolution, by combining: (1) deformation experiments on rock analogs, (2) numerical modeling of grain-scale structural and metamorphic processes, and (3) observations of natural microstructures using modern optical and analytical methods. An important goal is to address questions of relevance to larger-scale problems in geodynamics, such as the relationship between microstructure evolution and strain localization, bridging the microscopic and macroscopic scales. The education component of the lab focuses on bringing both an intuitive and quantitative understanding of the microscale processes associated with Earth deformation to a wide audience, from high school students and teachers, to college students and professors. Please visit the Projects link for examples of our research and outreach efforts.