Learning Geologic Time in the Field

Abstract

The lecture format for teaching the geologic time scale in introductory geology courses can result in memorization and regurgitation of nomenclature and dates. The professor may attempt to provide a historical context through lecture and laboratory exercises, but the relatively large number of students often prohibits going into the field. In order to provide a field-based context for understanding the geologic time scale, students can do an inquiry-based field project that includes a service-learning component. Over the course of the semester, each student collects an igneous, sedimentary, and metamorphic rock from outcrop exposures in the region. They construct a report from their samples that includes: (1) a complete description; (2) an analysis of the processes by which each sample forms; and (3) a geologic history that explains how each sample fits into the regional geology. The geologic history provides the context and incentive for learning the nomenclature and dates of the geologic time scale. A review of course evaluations suggests that students learn the nomenclature and dates of the geologic time scale better by using this approach than through lecture and lab. Anecdotal statements from the evaluations show that the students gain confidence from the project because they apply concepts learned in lecture. Students also comment that the service-learning component provides a sense of ownership in the project.