Differential Taphonomy of Shells
Summary
This is a several week activity in which students evaluate the differential taphonomy of shells tumbled in carbonate sand as compared to silica sand.
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Context
Audience
This is a 10 week lab activity in an introductory course on historical geology (Earth and Life through Time).
Skills and concepts that students must have mastered
Students need basic knowledge of minerals and hardness and fossilization. They need basic knowledge of types of organisms that fossilize as compared to those that rarell fossilize.
How the activity is situated in the course
This is the culminating project in the lab course.
Goals
Content/concepts goals for this activity
Students learn how differently shaped shells respond to weeks of tumbling in two different sand media. They learn to evaluate the likelihood of fossilization of various types of organisms.
Higher order thinking skills goals for this activity
Students develop hypotheses about the outcome of the experiment in the first week. They test their hypotheses against the final results,
Other skills goals for this activity
Students write the results of the experiment as answers to a series of questions. They are asked to apply the results to other possible situations. Students either write the answers in class or as a short paper.
Description and Teaching Materials
Five different mollusc shells are tumbled for 3 to 4 days per week, over 10 weeks. Shells are separately tumbled in silica versus carbonate sand. Students compare the effect of the tumbling on different shell shapes and in different sediments.
Shell Taphonomy (Microsoft Word 65kB Apr12 17)
Shell Taphonomy (Microsoft Word 65kB Apr12 17)
Teaching Notes and Tips
A variety of shell types and shapes works best. Have a set of 5 untumbled shells for comparison.
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Assessment
Students describe the results and propose explanations. Students apply what they have learned to other hypothetical situations.