Mudcracks - What's It Good For?

Scott Brande, University of Alabama at Birmingham
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Summary

Many terrestrial sedimentary processes are not difficult to observe, describe, and interpret. Yet many of these dynamic processes are not limited to the Earth. One example is the formation of mudcracks that provide critical evidence of the presence of liquid water saturating a fine-grained sediment and then evaporating. The documentation and analysis of this process can provide insight into geologic and environmental conditions on other planets (Mars?). Images and video snips are used to engage students who must attend to careful observation, description, and interpretation (qualitative and quantitative) from laboratory and field examples.

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Context

Audience

Undergraduate introductory physical geology for non-majors and majors. Sedimentary geology for geoscience majors.

Skills and concepts that students must have mastered

A brief introduction to fine-grained sediment. Estimate of angle at intersection of two straight non-parallel lines.

How the activity is situated in the course

A short exercise as part of a lecture on sedimentary rock.

Goals

Content/concepts goals for this activity

Attention during observation of dynamic development of mudcrack, and description of its geometry and shape. Accurate description of mechanical responses of saturated mud to conditions of water evaporation. Eyeball (quantitative) measurement of angle between two intersecting straight lines.

Higher order thinking skills goals for this activity

Observation and eyeball estimation of angles. Transferring understanding of mudcrack formation in a laboratory setting to an interpretation of mudcrack formation in a field setting.

This exercise is what I call a "multimodal" response exercise, because it requires observation of images and video, attention to detail, the writing
of descriptions and explanations in words, the sketching of a mudcrack shapes, the discussing of ideas with nearby peers, and the transfer of understanding of the terrestrial process of mudcrack formation to another planet. This extrapolation opens a further avenue for discussion about the fundamental nature of terrestrial processes that should be universal wherever the appropriate physical conditions are found.

Other skills goals for this activity

Careful observation of images and video snip. Writing descriptions, making sketches, discussing observations and interpretations with peers.

Description and Teaching Materials

Simple handout of video tutorial document individually to each student. Instructor clicks links that automatically play the selected video snips, streamed from Youtube under EZSnips control.
'Student handout for Mudcracks - All Cracked Up!' (Microsoft Word 2007 (.docx) 973kB Jun6 17)
'Student handout for Mudcracks' (Acrobat (PDF) 298kB Jun6 17)


Teaching Notes and Tips

See above.

Assessment

Student handouts are collected for assessment. Evaluation of handouts dependent upon the local instructor's objectives (e.g., degree of detail required, amount and level of description and interpretation, etc.). Instructor may modify content as needed.

References and Resources

Document files contain hyperlinks to online resources.
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