The Pet Rock Project - Developing Professional Communication in a Petrology Course

Darrell Henry, Professor of Geology and Geophysics, Louisiana State University

This material is replicated on a number of sites as part of the SERC Pedagogic Service Project


The pet rock project is an almost semester-long project in which students randomly select a rock and follows all of the steps a petrologist would take to interpret a rock from a known area (Beartooth Mountains, MT and WY). After preliminary input from the instructor, each student presents the revised results of this study in a written form comparable to a professional journal article, and in an oral format comparable a presentation at professional meeting.

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Learning Goals

GEOL 3041\\2009-PetrologyLabStudents

Petrology students will (1) obtain research experience within the context of the Igneous and Metamorphic petrology class and (2) learn to effectively communicate the results of their research in a written and oral form.

A student should be able to define, interpret, apply and analyze information and concepts related to the following topics:

  • identification and classification of igneous and metamorphic rocks in hand sample and thin section
  • textural evolution and its relation to formation history of igneous and metamorphic rocks
  • geochemical evidence for sources and evolution of igneous and metamorphic rocks
  • development of igneous and metamorphic rocks under a variety of tectonic environments

In addition, because this is a communications-intensive course, a student should be able to:

  • effectively communicate petrologic concepts and research in both oral and written forms

Context for Use

These projects (notice of intent, project proposal, project report, project review roundtable) are best suited for upper-level, capstone courses. Students should be well-versed in their discipline's content-knowledge and research-techniques, so that the emphasis can be placed on the professional communication of the content and research.

Description and Teaching Materials

The Pet Rock Project is designed to give petrology students experience in the petrographic and analytical methods and in the approaches taken by petrologists to solve a petrologic problem. Students will gather their own data and integrate that information into a geological framework to address broader-scale petrology questions.

The petrology students will use the results of the data that they acquired together with the background literature for the area to communicate their findings. These results will be presented in written form as if it were intended for a professional petrology journal and in an oral form comparable to one that could be given at a professional geology meeting.

This project runs in the background of the petrology class during the initial part of the semester while each student acquires the petrologic skills to make more sophisticated interpretations. However, during the semester each student must make continuous progress and follow a series of steps to be able to produce a robust petrologic study. The steps include:

  • hand sample description and rock preparation
  • petrographic description of the thin section as it relates to the genesis of the rock sample
  • acquisition of images (petrographic or cathodoluminescent) used for interpretation and further analytical studies
  • micro-analytical studies of the thin section in which students spend several hours with the instructor using the electron microprobe and/or SEM to identify more difficult minerals with certainty, to attain high quality digital backscattered images and to obtain electron microprobe analyses of selected minerals that will aid in the interpretation of the rock sample
  • background literature research on the geologic, tectonic and petrologic setting of the sample
  • preparation of preliminary 10-page written report and 10-12 minute oral presentation that will be evaluated by the instructor and the Communications Across the Curriculum staff, and then revised by each student
  • presentation of the final oral report to the class and completion of the revised written report.

Teaching Notes and Tips

The professional communication assignments are inherently imbedded within a professional scientific research project. A comprehensive description of the major research project with associated communication deliverables is linked below.

GEOL 3041 Pet Rock Project Timeline and Logistics (Acrobat (PDF) 208kB Nov2 09)


The grades are based on performance on a combination of lab and homework exercises, the two lecture exams, oral presentations and written project reports. While the 2 major exams are significantly weighted, the majority of the graded work is on the professional communication projects (Lab reports; Research papers; Oral Presentations), because it is only through true acquisition of the scientific content that these projects can be executed significantly.

The breakdown of weighting of scores is:

  • Igneous lecture exam - 20%
  • Metamorphic (igneous) lecture exam - 20%
  • Igneous Project Report - 10%
  • Pet Rock Presentation and Report - 20%
  • Volcano presentations - 5%
  • Group lab reports and individual homework - 25%

The assessment of the oral presentations and project report includes an additional facet to ensure a high level of professionalism on the part of students. They are each responsible for evaluating their peers using the same rubrics (linked below) I use to assess their work. Thoughtful completion of the evaluation rubric is emphasized by incorporating this exercise into the final grades of both the presenter and the evaluator.

GEOL 3041 Oral Presentation Grading Rubric (Acrobat (PDF) 31kB Nov2 09)

GEOL 3041 Writing Assignment Grading Rubric (Microsoft Word 64kB Nov5 09)

References and Resources

Identify campus, community, and virtual resources available to students at your institution. Many colleges and universities have Writing across the Curriculum programs, writing labs, speech tutors, and other support centers for academic excellence.