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Describe and Interpret Images: Folded Strata

This material is replicated on a number of sites as part of the SERC Pedagogic Service Project
Initial Publication Date: September 7, 2006 | Reviewed: June 13, 2012


Have students describe and interpret images rather than doing the description and interpretation for them. In class, have students make a simple sketch of an outcrop shown in a slide (or computer projection) then discuss possible interpretations. For example, show them a picture of the Dent de Morcles, with its convoluted strata, ask them to do a rough drawing and to summarize the probable history of the rock exposed in that mountainside.

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Learning Goals

During this exercise, students will:
  • Develop their observation and interpretation skills
  • Apply prior knowledge to a problem
  • Connect abstract geological concepts to the real world

Context for Use

One of these exercises might take 5-20 minutes within a lecture. The example described below would work for an introductory lecture on faulting, following a lecture on the laws of original horizontality and superposition.

Teaching Materials

The instructor will need a slide projector and slides of appropriate images, or an overhead projector and the wherewithal to print the appropriate overheads, or a computer projector.

Show the students the image linked to the thumbnail on the left, the Dent de Morcles from Switzerland. Ask them to sketch it, and then ask a series of questions. For each question, have the student turn to their neighbor and work out an answer. Have the students report their answers before asking the next question. Possible questions for students in entry-level geoscience courses could include:

  • Based on what we did last class, how do you explain the lines on the cliff face?
  • How would you expect the lines to be oriented according to what we learned last class?
  • What kind of topography is Switzerland known for?
  • How do you explain the shapes of the strata in the Dent de Morcles?

Teaching Notes and Tips

Doing this exercise regularly will help the students develop their observation and interpretive skills. The instructor could institute a "slide of the week" policy, in which the students interpret a slide dealing with the week's topic on the first day of class for each week.


After doing this exercise for a few weeks, you could then have an image interpretation exercise on the midterm or final. Alternatively, one week the image description could be a pop quiz. Instead of reporting answers verbally, each pair must write their names on a sheet of paper and turn them in. The pop quiz option may be necessary if the students are not taking the exercise (or their reading) seriously.

References and Resources

This kind of activity is described in Reynolds and Peacock (1988) .

Steve Reynolds, a geology professor at Arizona State University, also has a website (more info) , How to Observe Landscapes, that gives photograph of Monument Valley and a link to a "Geologist's Observations', which lists many observations with links to a page with questions and possible explanations.

For the original photo and more Dent De Morcles Information (more info) at USRA's Earth Science Picture of the Day (includes several useful links).

Sources for images: