ENVISIONING LARGE GEOLOGIC STRUCTURES FROM FIELD OBSERVATIONS: AN EXPERIMENTAL STUDY

Thinking about a structure in three dimensions, based on limited observations in the field, is an important skill required for field geologists, but many students have difficulty with it. To examine how people develop this skill, we are conducting an experimental study using "artificial outcrops." We are particularly interested in (a) how people mentally visualize large geologic structures from isolated small pieces of information; (b) how students who have trouble with this task differ from successful students and expert geoscientists, in terms of underlying spatial abilities, learning styles, and problem-solving strategies; and (c) how such a skill or strategy can be trained.

The "outcrops" are made out of plywood, and installed on grassy and wooded areas of our campus. A set of eight outcrops indicates the shape of a realistically scaled "geologic structure" that has been partly eroded and partly buried. The structures are an elongate basin and an anticline. Participants are expert geoscientists and novice learners (non-science majors at a local undergraduate college). An experimenter guides participants individually around a set of outcrops at their own pace, and they are allowed to take notes. When they finish observing the outcrops, they are asked to choose among an array of scale models the one that they think best represents the shape of the "buried structure." While they are still within sight of two outcrops, they are then asked to orient the model so that it is aligned with the actual structure in the real world. The scale models from which the participants choose are systematically varied on important properties, such as the ratio of the two axes, convexity/concavity, symmetry, and dip of the "rock" surfaces, so that we can identify the nature of the participants' mental images in detail based on which model they choose. They are asked to "think aloud" while choosing and orienting the model. This process is videotaped so that we can analyze their thought processes and develop strategy-training methods. They also take standard spatial tests and a questionnaire assessing their learning style (verbal vs. spatial).

Our poster will show early results from the study and discuss their potential implications for instruction. We hope to have feedback from both teaching practitioners and geoscience researchers.