Teachers Information and scoring rubric for "Plate Stratigraphy Assessment."

Return to the question.

Context and Use:

This assessment question was developed at Columbia University for use in an introductory level course for majors in Geology and Environmental Sciences, called Earth's Environmental Systems: Solid Earth. The course is one of series of three courses, which collectively cover the Atmosphere/Hydrosphere, the Lithosphere, and the Biosphere.

We used this as one of three question on the midterm (a closed-book, 75 minute in-class exam). The question would also work well as a homework assignment, on a take-home exam or open-book exam, or as an in-class small group discussion activity.

Prerequisite Knowledge:

This question is supposed to stimulate the student to pull together a lot of previously-unconnected information and concepts developed in lecture, reading, labs and the class field trip. To answer the question completely, the student needs to know and understand the following:

Reference:

The idea for this assessment question came from a classic paper:

Berger, W. H. and E. L. Winterer (1974). Plate Stratigraphy and the Fluctuating Carbonate Line. Pelagic Sediments: On Land and Under the Sea. K. J. Hsu and H. C. Jenkyns. Oxford, International Association of Sedimentologists: 11-98.

Scoring:

We gave 33 points maximum for this question.

Part A (maximum 27 points): "Develop a hypothesis…."

A well-documented hypothesis would have the following aspects or attributes:

This part of the question was scored to give 4 points for each of the bullet points above, up to a maximum of 27 points. Note that you didn't need to get every aspect of every bullet point correct to get full credit (the 8 bullet points could in theory have yielded 32 points of credit, but that level of interpretation was beyond what we were looking for. )

Other variants were possible, other than the exact story above. Credit was given for other sequences of events, provided that the events suggested were connected by a plausible and well-articulated process to the sediment types observed.

Part B (maximum 6 points): Design an experiment to test this hypothesis.

Whenever you see "design an experiment to test a hypothesis," a productive way to think about an answer is in three parts:

  1. what predictions are made by this hypothesis?

  2. what observations can I make that will support or refute one of these predictions?

  3. if the hypothesis is true what should I see when I make those observations, and conversely if the hypothesis is false what might I see when I make those same observations?

The hypothesis from part 1 makes dozens of predictions. You only need to test one prediction in your experiment. Examples:

In scoring this part of the question, 2 points were given for a plausible plan of action, 2 points for detailing what observations you would make when you carried out the plan, and 2 points for explaining how the proposed observations would support or contradict the hypothesis.

DLESE resource created by Kim Kastens, Lamont-Doherty Earth Observatory, Palisades, NY 10964; kastens@ldeo.columbia.edu; October 2000.