Metamorphic Rocks Lab

This page authored by Hannah Scherer, Stanford University.
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Summary

Photo of schist in Death Valley
Garnet-bearing schist in Monarch Canyon, Death Valley. Details
In this introductory geology lab, students are introduced to the processes involved in metamorphism through hands-on study of rock samples. They first examine three suites of rocks (regional metamorphism of mudstone, high-P/low-T metamorphism of basalt, and high-P/high-T metamorphism of basalt). Students then describe rocks with different metamorphic textures and other protoliths. They also examine key metamorphic minerals and infer the metamorphic conditions under which they are stable based on their observations of the rocks. Students answer summary questions at the end of the lab.

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Learning Goals

By the end of this lab, students should be able to:
  1. Define metamorphic rocks, describe how they are classified, and give several examples;
  2. Describe the factors that influence the composition and appearance of metamorphic rocks, and how those factors vary within the earth's crust;
  3. Describe how metamorphism and tectonics are related;
  4. Make observations using a hand lens and document their observations through writing and sketching;
  5. Use what they have learned about igneous and sedimentary rocks in order to make statements about how these rocks change during metamorphism.

Context for Use

This activity was designed for use in an activity-based undergraduate introductory geology course at a large research university. The class size can vary, but is usually 40-50 students working in groups of 2-3 people. At least 2 hours are needed for the activity. Including the mineral identification part, it will take about 2.5-3 hours. Each student has a handout and their own hand lens. Dilute HCl is available for them to test for calcite.

This activity was designed as the main metamorphic rock lesson. It follows igneous and sedimentary rock classification and identification. In the class preceding this activity, students learn about regional deformation (folds and faults) by looking at geologic maps.

Pieces of this activity may be used on their own in a different setting, but access to appropriate rock and mineral samples is essential.

Description and Teaching Materials

Student Handout (Microsoft Word 55kB Jul9 08)
Student Handout (KEY) (Microsoft Word 60kB Jul9 08)
Choreography for class (Microsoft Word 45kB Jul9 08)
Metamorphic Mineral Data Sheet (Microsoft Word 39kB Jul9 08)
Metamorphic Rocks Terms and Concepts (before class) (Microsoft Word 26kB Jul9 08)
Students are assigned a reading on metamorphic rocks to be completed before class. They are given a list of terms to pay attention to while reading.

The in-class activity is described for the students in the Student Handout. They are also given a mineral data sheet to record their observations. An example of the "choreography" for a 1 hr and 50 min class is provided with suggestions for background material to cover during the activity.

Assessment

This is not a graded activity; students have access to the answer key once they have completed the lab so they can check their work and ask questions during the next class meeting.

Students identify metamorphic rocks and answer questions about them on an exam.

References and Resources

Reading assigned to students prior to doing the activity:
Metamorphism and Metamorphic Rocks by Stephen A. Nelson, Tulane University