Teach the Earth > Structural Geology > 2004 Workshop > Long demo set #2

Long Demonstrations, Set #2

Session #3 (Tuesday 8:30) , repeated in Session #7 (Thursday 3:30)



L2A: Using the Autocorrelation Function in NIH-Image to Define Shape Preferred Orientations in Rocks and on Mars (Cameron Davidson, Carleton College). Humans are very good at spotting patterns at all scales including subtle variations in foliation at the outcrop and thin section scale to patterned ground on Mars. However, we are not very good at quantifying these variations other than saying a rock is well-foliated or not foliated. In this session we will use the autocorrelation function in NIH-Image to quantify the shape-preferred orientation in foliated tonalities from British Columbia and to define the preferred orientation present in various patterned ground terrain on Mars. NIH-Image is quick and easy to use, is free, and runs on Mac and PC platforms.

L2B: A Primer on the Use of Focal Mechanism Solutions in Analysis of Active Structures (Vince Cronin, Baylor University). The goal is to teach student geologists (at a senior undergraduate level or above) what an earthquake focal-mechanism solution is, something about how it is derived by seismologists, and how to employ them to derive useful information about active structures. This is not a course for seismologists – needed is a general familiarity with plotting lines and planes on a stereonet, but a working knowledge of seismology or facility with higher mathematics is not required.

L2C: Evolution of Normal Fault Systems During Progressive Deformation and Sand Box Experiments on Thrust Belt Development (Robert Burger, Smith College, and Ron Harris, Brigham Young University). This activity is based on QuickTime movies and color digital photographs derived from sandbox experiments that produce normal faults in a variety of boundary conditions following experiments developed by Ken McClay. Students view specially edited movies to gain awareness of the evolution of normal faults systems. They then investigate the formation and evolution of a fault system for a particular structural setting by tracing and labeling individual faults on a set of photographs taken at regular intervals during an experiment. This activity helps students develop an awareness of fault initiation, propagation, rotation, and inactivation during progressive deformation. No description available for Harris' portion of demonstration.

L2D: Problem-Based Learning (PBL): What it is, a Demonstration, and a Discussion on How to Plan and Implement a PBL Project (Dave Mogk, Montana State University). Problem-based learning is an educational approach that organizes curriculum and instruction around carefully crafted "ill-structured" problems. Students gather and apply knowledge from multiple disciplines in their quest for solutions as they develop critical thinking, problem solving, and collaborative skills. This session will present the basic philosophy and guidelines of PBL, an example project will demonstrate a term-long project that integrates structural geology and metamorphic petrology towards an interpretation of the Archean basement of SW Montana, and a group discussion will explore additional opportunities to use PBL in structural geology courses.

L2E: Composite session on the use of analog materials, with the following 6 short presentations:
  • Joints in a Cornstarch Analogue (Juliet Crider, Western Washington University): Joints are very important to problems in applied geology (fluid flow, slope stability), but commonly receive short shrift in undergraduate structural geology courses. Desiccated cornstarch-water mixture makes an excellent analogue for jointed rock, and provides an interactive introduction to some important features of joints and joint sets. In this session you will work in groups to map and examine your own jointed outcrop-in-a-petri-dish. Interpret relative ages through abutting relationships, examine joint intersection angles, use joint surface textures to determine joint propagation direction, and evaluate the role of flaws in joint initiation.
  • What Controls Rheology? (Dyanna Czeck, University of Wisconsin, Milwaukee). A short laboratory exercise, conducted by students, is used to illustrate the multiple factors that contribute to rocks' varied responses to deformation. Analogue materials (play-doh, notebook springs, butter, silly putty, plastic bags, etc.) are used to illustrate many of the controlling factors such as lithology, stress, temperature, confining pressure, strain rate, preexisting weaknesses, and accumulated strain. The analogue experiments are presented in conjunction with parallel data from deformation experiments and field studies. The tandem presentation of analogue experiment and real data requires the students to obtain a natural "feel" for rheologic parameters and more exhaustively analyze the important conclusions obtained from field and deformation experiment data.
  • Play with Your Food (and Other Things Not Allowed in School) (Vicki Hansen, University of Minnesota, Duluth) Short demonstrations involving food, rubber bands, rubber balls and other goodies show students that they know a lot more about rheology-that strange word that they have never heard that is the key to structure-than they think! These demos, which can be used across the curriculum, help students look to their own experiences for understanding (and they provide highlights to refer to again and again and again).
  • Getting to the Third Dimension: Play-doh and Other Aids to 3D Flinn Plots (Carol Ormand, Wittenberg University) No description available.
  • Shear Fracturing of Yogurt (Jaime Toro, West Virginia University). Surprisingly, a cup of yogurt fresh from the grocery store provides an ideal analogue material for quickly illustrating the geometry and kinematics of shear fractures. Students are asked to carefully squeeze with their hands a cup of Brown Cow yogurt. The plan view of the cup is an excellent strain marker: It deforms from a circle to an ellipse which allows them to quantify the strain. Usually one or more sets of conjugate shear fractures develop in the deformed yogurt. The geometry of the fracture sets can be sketched and the sense of shear can be observed by carefully releasing the deformation and imposing it a second time. As a bonus the students can eat their experimental material once they are finished.
  • Using Charleston Chew Candy Bars as an Analog for Rock Rheology (Arlo Weil, Bryn Mawr College) As a proactive learning exercise before my structure class gets into the nitty gritty of rheology, we spend a lecture undertaking qualitative strain rate, temperature, and confining pressure experiments on Charleston Chew candy bars. These experiments, along with several given assumptions, allow the students to accurately predict the deformation response of natural materials in the Earth to external stresses under different conditions. This session will provide the basic structure, necessary tools, and goals of my exercise, which can then be modified and incorporated into any undergraduate structural geology curriculum.
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