Cutting Edge > Courses > Structural Geology > Structure, Geophysics, and Tectonics 2012 > Teaching Activities > Crust-Busting Faults

Crust-Busting Faults

George Davis, University of Arizona

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Summary

Students independently research a major ancient or active regional fault, and cogently describe map and cross sectional characteristics, kinematics, mechanics, and plate tectonic significance. They present results to classmates, teaching assistants, and instructors.

FAULTING, REGIONAL TECTONICS, PLATE TECTONICS

Context

Audience

Undergraduate structural geology

Skills and concepts that students must have mastered

This exercise comes at the very end of the course, following introduction to all of the major structures, and kinematics/mechanics that pertain.

How the activity is situated in the course

Culminating project that ultimately occupies 2 four-hour lab blocks, the second of which is the presentation.

Goals

Content/concepts goals for this activity

Understanding faulting, in all aspects, from subregional to plate tectonic, and from geometry through mechanics.

Higher order thinking skills goals for this activity

To apply knowledge of the physical, kinematic, dynamic, mechanical nature of faults; to see faults in a regional or active tectonic context; to make solid judgments in summarizing key material; to communicate results orally.

Other skills goals for this activity

Students will learn that regional-scale faults and shear zones are THE major structures in the upper and middle continental crust. From the standpoint of pedagogy, almost all of the main topics in structural geology can be connected with this framework: geometry, kinematics, deformation mechanisms, fracturing, folding, tectonites, shear zone theory, and tectonics. Furthermore, during presentations students come to grasp that each major class of faults has its own coherent array of distinguishing properties. It is the repetition of these distinguishing properties, for strike-slip versus normal versus thrust faults that becomes so apparent in the class presentations.

Description and Teaching Materials

Provide to the students a list of major regional faults (ancient and active) that the students may choose from. List includes all classes of faults. Students take full advantage (in best sense) of instructors and teaching assistants to gain guidance in locating a few key journal articles that form the backbone of the analysis. Provide handouts of one or two excellent examples from past semesters, which become templates of sorts. The following attachment contains the specific wording of the assignment as well as a list of choices of faults. The list is continuously updated.

Crust-Busting Faults (Microsoft Word 47kB Apr30 12)



Teaching Notes and Tips

I don't recommend falling into the 'trap' of power points in this exercise. Not only does power point create inefficiencies in moving through a large number of brief student presentation, but it also from the beginning sets a tone that implicitly 'invites' students to cut and paste beautiful published maps and sections from the journal literature, or from web sites. As soon as this begins to happen, control is lost in regard to whose work this really is. By having the students create 'by their own hand' derivative figures we have the chance to avoid concerns about 'cheating' and, more importantly, gain a clear sense for the decisions students made in determining what (of importance) to include. This past semester I found it helpful to devote an entire lab to a 'prep session.' Students brought in materials (maps, sections, etc) from the literature, and the teaching assistants 'walked' students through creating derivative diagrams.

Assessment

This is a graded exercise, with half the grade related to the write up and figures, and the other half related to the effectiveness of the oral presentation.

References and Resources

I am attaching here examples of student products. Both are ACTIVE crust-busting faults. Arthur Wickam chose the Wasatch fault, and gave me permission to share the scans. Sean Wright chose the Hayward fault, and he as well gave me permission to share the scans. Exemplars such as these should be handed out to the class at the time the assignment is made, so that everyone in the class gains and immediate understanding of what is expected. For each of the attachments, p.1=map, p.2=section, p.3=descriptive, p.4=kinematics & mechanics, p.5=tectonics, and p.6=references. Hayward Fault example (Microsoft Word 357kB May23 12) Wasatch Fault example ( 305kB May23 12)


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