INSTRUMENTATION-BASED GEOCHEMISTRY ASSIGNMENTS IN UNDERGRADUATE COURSE WORK: A CASE STUDY OF SUCCESS, FAILURE, AND REVISION

The increasing use of geochemical instrumentation throughout the geosciences places added responsibility on undergraduate geology departments to provide instrumentation experiences to students planning post-baccalaureate professional and graduate school careers. The Middle Tennessee State University Department of Geosciences utilizes a sequence of courses (mineralogy, petrology, geochemistry, applied geochemistry) to introduce and train students in the use of on-campus geochemical instrumentation (XRF, ICP-MS, SEM). Students enrolled in required mineralogy and petrology courses are introduced to sample preparation techniques and basic principles of analytical instrumentation through limited hands-on laboratory exercises. Students enrolled in elective geochemistry and applied geochemistry courses participate in extensive sample preparation and analytical training, and are required to carry out semester-long independent or team projects to demonstrate proficiency using one or more analytical instruments. Instrumentation skills and experiences gained by students in geochemistry courses clearly foster student knowledge and enthusiasm. This is evidenced by an increased percentage of MTSU geoscience majors completing geochemistry-based senior research and pursuing graduate degrees in geochemistry-related fields. However, student assessments in mineralogy and petrology show that limited hands-on instrumentation laboratory exercises have little impact on student learning and retention of course concepts requiring interpretation of geochemical data. Newly revised mineralogy and petrology lab exercises require students to first identify and describe type(s) of geochemical data, instrumentation, and sample preparation necessary to solve an assigned problem. After completing the analytical description, students receive a data set needed to perform calculations or construct graphs in order to solve the problem. Preliminary assessments suggest this approach more effectively facilitates student understanding of fundamental differences between types of geochemical data (e.g. major element, trace element, isotope, etc.), and reinforces course concepts dependent upon geochemical data presentation and interpretation.