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Cretaceous-Tertiary Boundary: A Great Enigma

This page was written by Jen Aschoff as part of the DLESE Community Services Project: Integrating Research in Education.

The Z-coal at the top of the Hell Creek Formation marking K-T boundary in Montana.
The Z-coal at the top of the Hell Creek Formation marking K-T boundary in Montana. Details

What is the nature of the K-T boundary and how is it related to the extinction of the Dinosaurs?

There are numerous suitable thought pathways by which to explore such a question. Below, we have suggested one such pathway.


Read more about this pathway to discovery here...

In this pathway, we begin with the most basic questions, provide resources to help answer these questions, and progress to more complex questions. The end result is not an answer, but a better understanding of contemporary arguments and supporting data concerned with the "big question". Students and instructors are encouraged to discuss favored hypotheses and provide data and reasoning to support a particular "favored" hypothesis.

  1. What is mass extinction?
  2. What criteria must be present to infer a mass extinction? And, which of these criteria exist for the Cretaceous-Tertiary extinction?
  3. Why do certain groups of organisms survive while others diminish?
  4. What groups of organisms were affected by the K-T "event"? What does this tell us about possible causes of the extinction?
  5. What ideas have been proposed to explain the Cretaceous-Tertiary mass extinction?
  6. What geologic problems or limitations exist that make the K-T boundary and extinction question inherently difficult questions to answer?


Pathway to Discovery:

1. What is mass extinction?

Helpful Resources:

2. What criteria must be present to infer a mass extinction? And, which of these criteria exist for the Cretaceous-Tertiary extinction?

Helpful Resources:

3. Why do certain groups of organisms survive while others diminish?

Helpful Resources:

4. What groups of organisms were affected by the K-T "event"? What does this tell us about possible causes of the extinction?

Helpful Resources:

5. What ideas have been proposed to explain the Cretaceous-Tertiary mass extinction?

Helpful Resources:

6. What geologic problems or limitations exist that make the K-T boundary and extinction question inherently difficult questions to answer?

Suggested Post-exercise Group Discussion Questions:





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