Cutting Edge > Structural Geology > Structure, Geophysics, and Tectonics 2012 > Teaching Activities > Sidewalk Fold-and-Thrust Belts

Sidewalk Fold-and-Thrust Belts

Martha Growdon, SUNY Oneonta

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Summary

Students work in small groups to re-create sidewalk-scale fault bend folds and fault propagation folds from textbook images.

Context

Audience

This activity is for a senior-level structural geology class required of geology majors.

Skills and concepts that students must have mastered

Students should be at the very beginning of the class segment on fold-and-thrust belts. They may or may not have yet read the textbook chapter on fault-related folds.

How the activity is situated in the course

This is an exercise that introduces the segment of the course of ramp-flat geometries in fold-and-thrust belts.

Goals

Content/concepts goals for this activity

Students will mimic through re-creation the geometric relationships among hangingwall and footwall layers in fault bend and fault propagation folds.

Higher order thinking skills goals for this activity

Students will develop a set of rules that governs geometries for fault-related folds in fold and thrust belts.
Students will think critically about geometries of layers in the hangingwall and footwall with respect to fault ramps and flats.

Other skills goals for this activity

Collaborative group work

Description and Teaching Materials

Materials necessary:
- sidewalk chalk
- meter sticks
- large protractors (can do with small ones too, but if you have a ginormous one, that's super!)
- textbook diagram of fault bend fold and fault propagation fold

Instructions to instructor:
Separate the class in to small groups (4-5 students in each. This activity actually works better with larger groups (rather than pairs/threes) because a core of students will take the initiative and start the recreation. The more hesitant students will watch closely and will pipe up when they see the go-getters missing a critical component. It's so neat to watch the group dynamics in this exercise!)

Instruct each group to recreate their assigned diagram (just do 1 per group!) on a sidewalk-scale. Tell them to pay particular attention to the geometries of lines and angles during the exercise. Once they have completed the scaled drawing in sidewalk chalk, you can choose to have them study the geometries and come up with a set of rules for these geometries, or you can lead that discussion (depending on the time you have for this).

Fault bend fold image
fault propagation fold development image


Teaching Notes and Tips

This is a very easy, outdoor, exercise that the students enjoy, especially in the first few warm days of spring. They learn more than they think they will, and they wind up with a better feeling for ramp-flat geometries than they would from lecture! I was pleasantly surprised when I did this on a whim, because I thought at the time it was a total cop-out! How wrong I was!

Assessment

Students use their observations to develop a set of rules that govern the geometries of fault-related folds in fold and thrust belts. They apply these rules to future assignments/activities.

References and Resources

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