Research Experiences in a Mineralogy Class

Dave Mogk, Montana State University

Summary

Related Links

Geochemical Instrumentation and Techniques - from Integrating Research and Education

One of the goals of my Mineralogy class is to demonstrate how the principles and content covered in class can be applied to questions of geologic interest or that have practical applications to society or industry. This is an early step towards introducing students to authentic research projects. The general theme of these projects is characterization of Earth materials, and typically involves collection of samples in the field (if possible), hand sample observation, petrographic analysis, and further analysis using X-ray powder diffraction and electron beam techniques such as scanning electron microscopy (SEM) and back-scattered electron (BSE) imaging and elemental analysis using energy dispersive spectroscopy (EDS).

Context

Students working on XRD
My Mineralogy course is the first course for geology majors in our curriculum, is taught at the sophomore level, and has a year of introductory chemistry as a prerequisite. This course also has a university "Core Curriculum" designation as a research-intensive course.

These projects have been done in a number of different contexts.

  • We have worked with local mines (Stillwater Mining, Golden Sunlight Mine) to collect samples that will address questions of immediate interest to these operations. Students have looked at primary igneous, ore, and alteration mineralogy of these deposits. Samples were collected from areas of interest from these mines in consultation with mine geologists, and formal reports were submitted with the results of the students' analyses.
  • Within our department, mineralogy students have been paired with other faculty and graduate students to work on mineralogic problems related to ongoing research. The faculty/graduate student mentors provide the samples, help students define the nature of the problem or question, and provide the geologic context for interpreting the results. Students design a research project that will characterize the identity, morphology, structure state, and composition of the minerals of interest, and then write a consulting report to their sponsors with the results. We have analyzed samples of dinosaur bones and egg fragments, sediments from turbidite deposits, ore minerals, alteration in fault zones, saline seep evaporites and much more.
  • This has been a great way to initiate our incoming majors into the scholarly life of the department. In many cases, the mineralogy students did feasibility studies for graduate students that led to new or continued lines of research. In some cases definitive results contributed to interpretations for ongoing research projects.

Audience

This is the first "for-majors" course offered in the second year in our curriculum. The Introductory Physical Geology course and a year of introductory chemistry are pre-requisites.

Class size

Enrollments in this class have been steady at 30 +/-2 for numerous years.

How the activity is situated in the course

The research experience is conducted during the latter part of the course, and accounts for ~20% of the total course grade. The research project is done after students have had an introduction to the physical properties of minerals, and have been introduced to hand sample identification of minerals. The research project is continuously addressed in stages (sample selection, sample preparation, analysis), while regular course work in crystal chemistry, crystallography, and mineral optics are being taught in lecture and lab. In some cases, a field trip is conducted early in the semester to collect the samples that will be analyzed. In other cases, students will identify their particular interests (e.g. paleontology, igneous petrology, structural geology) and we will pair the students with faculty or graduate student mentors early in the term. This gives the students a chance to identify samples that they will work on, read some of the background literature for context, and work with their mentors to understand the larger context of their work. Mid-way through the semester students undertake appropriate sample preparation (cutting thin sections, preparing powders for XRD, making SEM mounts). XRD and SEM analysis by students takes about a month to finish, and the final week of the term is used for data representation and report writing.

Students working on SEM

Goals

In developing their research project to characterize their sample(s), students are expected to:

  • Define their research question about a given type of Earth material
  • Select appropriate samples to address the question
  • Do the required sample preparation for analytical procedures
  • Follow analytical protocols on instruments (XRD, SEM/BSE/EDS) (done under the supervision of the instructor) to collect data and images
  • Integrate data from two or more independent sets of analyses to write a comprehensive report on the nature of their Earth materials.

Description

Students work independently or in small groups to identify minerals, and characterize their morphology, texture and composition to address a problem of geologic, economic, or societal significance. Students either collect their own samples (if possible) or work with samples provided by mentors to: a) conduct petrographic analysis, b) use powder XRD methods to identify samples, and c) use SEM/BSE/EDS and possibly CL methods to characterize the size, distribution, morphology and composition of minerals of interest. The results of these analyses are then presented in a written report to the mentors to provide information that contributes to understanding of geologic process, geologic history, environmental, or economic applications.

Notes, Tips, and Logistical Considerations

Benefits

  • Students are quite excited about contributing to authentic research results
  • Students are also quite excited about the opportunity to use modern analytical instruments (powder XRD and SEM/BSE/EDS/CL).
  • Students gain a sense of ownership in their projects, and they also gain self-confidence that they CAN DO science!
  • Students are inaugurated into the community of practice of professional scientists, and
  • Students develop close interpersonal ties with faculty in the department (whom they have not yet met or had a course from), graduate students, and other students in the class working on similar or related projects.
  • Students get a sense that all the "book learning" in class (crystallography, crystal chemistry) is indeed useful, and that the occurrence, distribution, composition of minerals in aggregate tell a story about physical conditions, geologic history, or have practical applications to geologic and societal problems.

Caveats

  • Cost of beam time: we do have to cover costs to operate the instruments, and also for expendables. We have charged an extra lab fee to partially offset these real costs, and we have periodically received an infusion of funds from the VP Academic Affairs office to help offset these costs.
  • TIME: this takes an inordinate amount of faculty time to supervise students on these modern instruments (in small groups or individually--you can't just turn them loose on an X-ray or electron beam instrument)! I do have some TA help, and the lab staff is very good about helping. But the bottom line is that I schedule a large amount of out-of-class time to meet with students (according to their schedules) so that everyone gets a chance to operate the instruments during the last month of class.

BUT, IT'S WORTH IT! THE REWARDS ARE GREAT AS THE STUDENTS TAKE THEIR FIRST STEPS TOWARDS BECOMING CONTRIBUTING SCIENTISTS.

Assessment

  • Formative assessments are used throughout the project to make sure that students are on track towards a successful completion of their projects. These include a) a two-page research proposal, based on their conversations with mentors and background reading, about what the central research question is and why it is important; b) routine checks to make sure that sample preparation has been completed on time, instrument time has been scheduled, etc. c) oral interviews with students to review analytical results--they must be able to articulate what they did, why, and what the results mean.
  • Final research report that includes the statement of the problem, sample selection and preparation, analytical methods, key results (text written to images and spectra obtained), and final interpretation that presents these data in a meaningful context. The reports are scored against a rubric, and feedback is also solicited from the mentors who provided the samples.

Teaching Materials