What Do the Numbers Mean? Course Projects and the Evaluation of Trace Element Data Acquired Using a Portable X-Ray Fluorescence Instrument

“Minor things can become moments of great revelation when encountered for the first time.” Margot Fonteyn

Frequently cited goals of an effective science education are enabling students to integrate quantitative reasoning, evaluating data, and the ability to recognize, formulate and test hypotheses; without these skills a student is ill-equipped to undertake and complete research whether during a senior or post-graduate thesis or as a working scientist. To this end, many tout the worth of including a mini-research project in a course, but the time and expense required for data acquisition and analysis may put this beyond the reach of smaller programs. Students can learn to design a field or lab sampling campaign and acquire trace element data using a relatively inexpensive portable X-Ray Fluorescence (PXRF) spectrometer with relatively little time invested in training and the actual measurements. My students tested hypotheses related to emplacement of Columbia River basalts (e.g., evidence of flow inflation) by obtaining trace element transects of individual flows in cross-section. This project required students to use analytical standards to evaluate precision and accuracy of the data. By directly working with data in Excel, students improved their spreadsheet and plotting skills. They also interpreted results within the framework of hypotheses gleaned from reading carefully selected journal articles. Students expressed great satisfaction with the opportunity to learn and use these skills. This project set the stage for my continued research and expanded the research capabilities of students concurrently completing senior theses in our program. Furthermore it is valuable preparation for students who will undertake senior research with me in the coming year. The PXRF itself can readily be used for projects involving compositional analysis whether in traditional Mineralogy, Geochemistry, or Petrology courses or in courses examining soils, metals, or remediation projects.