Evaluating the lines of evidence for plate tectonics
In this in-class exercise, students compare several lines of evidence that support the ideas of continental drift and plate tectonics. Before the class meeting, each student is given a preparation assignment in which he/she studies one "continental drift" and one "ocean floor data" map. In class, students divide into teams of 3, with each team member having prepared different specialties. They discuss their respective maps and look for spatial patterns among the data.
- Students will identify patterns related to continental shapes, till distribution, and fossil distribution.
- Students will identify several physiographic features on the ocean floor.
- Students will determine age distribution of the oceanic crust.
- Students will determine marine sediment thickness distribution.
- Students will observe patterns between these physiographic features, oceanic crust ages, and marine sediment thickness.
- Goals and skills include map reading and interpretation, synthesis of multiple data sets, pattern identification, and oral communication in the context of group work.
Methods of GeoscienceThe overarching geoscience methods inherent in this activity are analyzing maps and identifying patterns among multiple datasets. In addition, some instructors may choose to intersperse short discussions throughout the activity about how the data were obtained that highlight geoscience methods. This could include identification of glacial features and deposits in the field; sampling and dating techniques to determine absolute ages of rocks; sediment sampling procedures; and instruments used to characterize the physiography of the ocean floor.
Context for Use
Description and Teaching Materials
During the next class meeting, students will divide into teams, each with one A, one B, and one C representative. Each student receives a handout, a map illustrating locations of mid-ocean ridges, and a map illustrating locations of deep-sea trenches. In teams, students first discuss the lines of evidence for continental drift. Then, they look at their ocean floor data and the ridge and trench maps to look for patterns among the maps. Finally, they come up with hypotheses for why the patterns exist. This activity sets the stage for subsequent discussions about plate tectonics, as well as the difference between continental drift and plate tectonics. I have included some example maps, but you may already have your own maps of oceanic crust ages, marine sediment thicknesses, and ocean physiography that would be equally suitable for this exercise.
- student handout and color maps for "evaluating the lines of evidence for plate tectonics" assignment (Acrobat (PDF) 1.3MB May14 12)
- preparation exercises for continental drift and plate tectonics activity (Microsoft Word 2007 (.docx) 103kB May14 12)