This activity was selected for the On the Cutting Edge Reviewed Teaching Collection
This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are
- Scientific Accuracy
- Alignment of Learning Goals, Activities, and Assessments
- Pedagogic Effectiveness
- Robustness (usability and dependability of all components)
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This page first made public: Jun 1, 2012
Structural geology laboratory on strain analysis. Emphasizes basic methods for determining strain from points, lines, ellipses, and polygons. Introduces two-dimensional strain using hyperboloidal geometry and projections. Students use the computer program EllipseFit to digitize and analyze images. Higher level material on hyperboloidal contouring, pre-strain fabrics, and three-dimensional analysis may be included.
Junior or senior level geology majors in structural geology laboratory.
Skills and concepts that students must have mastered
Students will have completed lectures on stress and finite strain theory. The topic of strain analysis should, ideally, have also been discussed in the lecture.
How the activity is situated in the course
Stand-alone lab activity, but can be incorporated into field exercise. This is a good introduction for students who may do a research project.
Content/concepts goals for this activity
Understanding strain analysis in two and three dimensions, determination of strain from points, lines, ellipses, and polygons.
Higher order thinking skills goals for this activity
Conceptualization of three-dimensional geometry and basic finite strain theory.
Other skills goals for this activity
Computer skills, download and install software from web, import diagrams into Adobe Illustrator, MS Word, LibreOffice and other programs for presentation.
Description and Teaching Materials
Strain Analysis Lab (Acrobat (PDF) 1.6MB May14 12)
Teaching Notes and Tips
The lab exercise requires digital images of deformed materials (conglomerates, sandstones, brachiopods, etc.) that can be scanned from the structural geology text or lab manual (e.g., Ragan, 2009; Ramsay and Huber, 1983; see references), taken from photographs of outcrops or thin sections, or found using web searches. For a short, in-lab, activity have students digitize brachiopod hinges (Wellman), and center points (Fry). Digitizing particles as polygons will take more time.
The students hand in reports on their analyses for grading.
References and Resources