Correlation
Summary
Rocks from different regions can be correlated by fossils, by rock type, and by absolute dates. This exercise is meant to illustrate to students that many different parts of a rock record can be correlated, but do not necessarily correlate the same thing.
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Context
Audience
The course is "Principles of Paleontology" and is typically taken by sophomore or junior geology majors. Prerequisites for the class are Physical Geology and/or Historical Geology.
Skills and concepts that students must have mastered
By this point in the course, students have been introduced to the geologic time scale. They should understand the relationship between rock facies (lithology) and environment. Students have already been introduced to biostratigraphy. Students also already have been taught about absolute dating techniques. Additionally, it is helpful if students already know a bit about microfossils and the difference between benthic and planktic foraminifera.
How the activity is situated in the course
This exercise usually occurs near mid-semester, after I've covered microfossils and have lectured on various types of stratigraphy. This is an in-class exercise (though I usually allow students to take it home until the next class if they wish).
Goals
Content/concepts goals for this activity
To goal is to understand different types of correlation in the rock record. Students need to understand that no single type of correlation can provide a complete picture of the earth in the past.
Higher order thinking skills goals for this activity
In the end, I ask students to attempt to interpret the complete story based upon the various correlations made. Students formulate a hypothesis and explain it.
Other skills goals for this activity
Description of the activity/assignment
Three hypothetical rock sections along an East-West transect are provided. Students correlate the three sections using the biostratigraphy of planktic forams (as a proxy for age), benthic forams (as a proxy of depth), and lithology (as a proxy of environment). Students are asked to provide an interpretation of the history of this depositional basin. An ash bed of known age is added and students are asked to determine if this new information affects their interpretation. Finally, an interesting lithologic feature is added, and students are asked to provide a geological explanation.
Determining whether students have met the goals
As with all exercises in this class, I do not assign a 'grade,' but rather mark the exercise completed or not-turned-in. I discuss the exercise in class the following period. Most students make a mistake in the lithologic correlation, which I explain. I read through their interpretations and explain what my interpretation is and also how theirs may or may not work.
More information about assessment tools and techniques.Teaching materials and tips
- Activity Description/Assignment:Exercise in Correlation (Microsoft Word 4.3MB Aug2 09)
- Instructors Notes: Two complications arise in this assignment. 1) There is some mixing of foraminifera where benthic forams may roll down hill, resulting in the appearance of shallower depths and there may be bioturbation such that older forams are mixed with younger. 2) some of the units pinch out landward, a topic which may be worth touching on during lecture.
- Solution Set:Key for correlation exercise (Microsoft Word 5.6MB May28 09)
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