Teaching with analog experiments – Millions of years in minutes
Jacqueline Reber, Iowa State University
,
,
,
,
One of the biggest challenges in teaching structural geology and tectonics is the temporal and spatial variability of processes. We need to link observations at the micro-scale to observations at lithospheric scale and we see deformation resulting from processes spanning a few seconds to millions of years. Having limited access to outcrops and being only able to see a snapshot in time makes it hard for students to grasp the dynamics and heterogeneity of deformation processes. I am using analog experiments in class to bridge this gap and help students develop intuition for deformation processes. Here I present a teaching laboratory that has been developed at Iowa State and is used for introductory structural geology classes at Iowa State and Macalester College, MN, in collaboration with Alan Chapman. This laboratory exercise takes place in weeks 6-8 of a 15 week semester after the students have learned the basics of brittle and ductile deformation. During the analog modeling laboratory exercise students experiment with brittle, ductile, and semi-brittle deformation and investigate the governing role of rheology on deformation. The exercise makes use of two simple shear machines and a Hele-Shaw cell where students report force-displacement-time data. Student teams working on different materials compare their findings and discuss limitations and advantages of the different materials and boundary conditions. After the completion of the experiments the students make the leap from the experimental results to real rocks and seismic events.