THE I-70 ROADCUT (COLORADO), A VIRTUAL GATEWAY TO INTRODUCTORY GEOLOGY

I-70 slices through tilted Permian to Cretaceous-aged sedimentary rocks of the Dakota Hogback and provides an extraordinary roadcut west of Denver where the principles of stratigraphy, depositional environments, sedimentary structures, and the vastness of geologic time can be observed in a natural setting. The roadcut is so extraordinary that it has its own highway sign dubbing it a “Point of Geological Interest”. Unfortunately, many geology instructors do not have the means to transport a large introductory geology class to this field site. However, the I-70 roadcut (and sites like it) can be readily and effectively adapted for use in a large introductory geology course.

On the first day of class, the “Point of Geological Interest” sign was projected and students were asked to consider to what geologic feature it might refer. Students offered many suggestions before they were shown a photo of the I-70 roadcut. This exercise got students involved in the course at the outset and provided students with a gateway to the course leading to further discussion on how geologists make observations.

Students were each assigned the task of obtaining a photograph of their own favorite “Point of Geological Interest” for presentation. Each class began with the “Point of Geological Interest” sign and was followed by a student’s photograph that related to the topic of that day’s lecture. Class discussion often returned to the photo throughout the lecture offering an opportunity for the students to practice their observational skills.

As a result of this simple exercise, each student had a stake in what was being taught and took ownership for some part of the class. Ultimately, the students came to class more frequently to avoid missing the occasion when their photo was included in the lecture.