Do sandbox models help students to visualise geologic structures and deformation?

We investigate the effects of incorporating sandbox deformation experiments on the geologic understanding of students in an upper level geology class, Tectonics and Orogeny. Scaled analogue modelling allows plate boundary processes, such as the development of a mountain belt, to be observed in real time in a classroom setting. The potential benefits of incorporating such activities into courses focussed on tectonics and structural geology seem obvious, but does exposure to such activities measurably improve spatial reasoning, and the ability to visualise realistic geologic structures?

The class consisted of 17 students with a range of previous experience in structural geology and field mapping, 13 of whom agreed to participate in this study. Deformation experiments were performed on a sandbox model designed for side-by-side experiments, allowing the effects of rheology on the same input deformation to be directly compared. Two sets of experiments were performed, focussing on extensional deformation and then convergence. For each set, the students engaged in a cycle of predicting the behaviour of models with different combinations of weak, intermediate and strong layers, and then evaluating and revising these predictions in the light of their experimental observations. Predictive sketches and reflections were collected before and after each set of experiments.

From responses to a post-course survey, the students not only enjoyed using the sandbox model, but felt that the experiments had a positive impact on their ability to visualise 3D geological structures. Pre- and post-testing, performed using a shortened (10-question) version of the Geologic Block Cross-Sectioning Test, indicated an improvement in the students' spatial reasoning skills, although the effect is somewhat muted by the more experienced students performing well on the pre-test. The students' sketches also suggested an increased understanding of expected deformation patterns (e.g., depiction of brittle/localised structures rather than ductile/distributed deformation) over the course of the experiments. Based on these results, use of sandbox models in the classroom not only increases student engagement, but also has a measurable effect on core spatial reasoning skills and geologic understanding.