A Field-Based, Writing Intensive Undergraduate Course on Pacific Northwest Geology

Journal of Geoscience Education, Nov 2006 by Buddington, Andrew M

To culminate the term, a final group project is required where the students create a virtual geologic field trip. Individual groups visit a site of their choosing, document their field observations, and with the help of the instructor and the campus webmaster, create a virtual field trip that is included in the class web site for a period of one year.

LABORATORY FIELD EXERCISES

The six required laboratory field trips offered during the term are two hours in length and consist of two igneous rock sites (one volcanic, one plutonic), two metamorphic sites, one fossiliferous sedimentary site, and one Quaternary glacial sediment site. At the outcrop, students are assigned to work in pairs and are provided with a topographic map and field equipment such as hammers, goggles, hand lens, and compass (with inclinometer). The objectives of the field visit are provided to the student along with a field method primer that summarizes the basics of making outcrop observations and how to write rock descriptions. To attend a field trip, each student is required to have a field notebook (which is for sale in the college bookstore). The objectives of the site visit are for students to learn how to: (1) locate field sites on a topographic map, (2) designate and record site numbers, (3) make rudimentary field observations including mineral and rock identification, rock texture and outcrop structure recognition, and the interpretation of relative age relationships, (4) effectively document field observations, including detailed note taking and the creation of outcrop sketches (or photographs) and, (5) collect and label a sample. During the first site visit, the instructor walks the students through an outcrop point-by-point emphasizing the importance of comprehensive documentation. For the remainder of the lab field trips, students are required to work in pairs without the direct guidance of the instructor. Using the Socratic Method, the instructor circulates among the groups to address specific questions, but emphasis is placed on self-discovery. Field notebooks are handed in following each field trip and are graded based on the observations documented and sketches created.

Each site is picked for a set of specific field relationships. For example, one field trip visits an outcrop of Columbia River basalt (CRB) that exhibits multiple lava flows. Prior to the visit, students are given a slide lecture on the Columbia River flood basalt province and they are provided with a handout of an idealized CRB flow stratigraphy. At the outcrop, students are directed to document the basalt and flow relations and ultimately to determine how many flows are exposed. The students are required to sketch the relationships they have observed. Because the students have been presented a slide lecture on CRB geology in advance of the site visit, this exercise becomes relevant and, in fact, exciting. Another laboratory field trip visits a Tertiary-aged granite roadcut that exhibits significant structure (e.g., small faults) that presented geotechnical engineering challenges to the road builders. Students make basic rock observations as well as measure fracture and fault sets that occur throughout the roadcut. Students are directed to the relationships of outcrop structure and weathering with respect to slope stability and geotechnical engineering techniques such as rock bolting and slope grading.