Bruce J Douglas
Senior Lecturer, Department of Earth and Atmospheric Sciences
Senior Lecturer and Director, IU Judson Mead Geologic Field Station Structural Geology, IUB
Phone: (812) 855-3848
My research is divided between investigations that concentrate on geologic problems and investigations into the learning processes of undergraduate students. For the geologic projects, there is an underlying theme that involves identification and quantification of the deformation mechanisms that result in permanent strain accumulation in a rock, which includes both brittle and ductile deformation mechanisms. These studies make use of natural and laboratory samples with applications in the upper and lower crust and upper mantle. The latter involve identification of the active deformation mechanisms responsible for controlling mantle rheology which in turn can be seen to control the seismic properties and lithosphere-asthenosphere coupling. I am also interested in the initiation and development of both thrust and normal faults with an emphasis on the initiation stages and the importance of preexisting fabrics or faults in the evolution of fault systems over time. The projects that address student learning involve those aspects of learning unique to the geologic sciences such as rock identification, geologic time/4D thinking, and learning in the field.
Ongoing geologic projects include:
- Fault development and fault reactivation based on kinematic models involving field data and analog model experiments. Field areas include southwestern Montana, central Oregon, and Greenland. These studies make use of excellent exposures of fault geometries that provide tight control on mechanical properties of these faults;
- Subduction zone coupling across an oceanic-continental boundary using a natural experiment created by the subduction of the Chile Rise. This project includes an investigation into the rheology of the mantle lithosphere beneath southern South America and the influence of the subduction of a spreading center on the overriding plate. This project includes petrographic and geochemical analysis of xenoliths with quantitative analysis of the stress levels, fabric development, and activation energies associated with dislocation creep within olivine;
- Development of Tertiary extensional basins in Oregon and Montana. These projects include normal fault geometries and the resulting development of extensional basins, in both pristine (Oregon) and previously deformed (Montana) rock sequences. These studies will lead to insights into the relative importance of the various geologic components including rock mechanics in extensional basin development. The role of fracture development as a means of creating ground water flow paths in terrains with inherently low permeable rocks is one important byproduct of this research;
- Residual stress release and the development of joints and fractures in metamorphic gneiss in SW Greenland with implications for nuclear waste storage in hard rock locations. This study takes advantage of pristine outcrops of bedrock recently exposed from beneath ice sheets.
Ongoing educational projects include:
- An extension of a broad area of research in cognition in real-time decision making scenarios applied to problem solving in field geology. Most field learning situations place an emphasis on problem-solving, which in the geologic context means purposeful mapping and investigation in a setting where students are unaware of the final “answer” and must make decisions in real time as their mental models of potential solutions evolve in response to ongoing data collection during the unfolding field problem.
- The development of curriculum that includes newly emerging geodetic data sets that include time series which can be analyzed to document near and real-time changes in the response of the Earth’s surface to various geological processes which impact humans such as earthquake hazards, water availability, and sea level changes.
- An investigation into how non-science majors incorporate new scientific material into their pre-existing framework of knowledge. Given the foreign nature of the material they are being asked to learn and the lack of experience in determining what is important to learn results in these students constantly being placed in learning situations where they being challenged to distinguish what key observations need to be made at any given time.