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...

Pathway to Discovery:

1. What is mass extinction?

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

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

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

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

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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:

  • Briefly summarize the observations that have been made concerning the K-T boundary and the extinction of dinosaurs.
  • Which extinction hypothesis best describes the observations that have been made about the K-T boundary?
  • Are there any problems with the science that has been done on this topic?
  • What are some possible avenues for future research on this question? Give an example of a project you could do to further our understanding of the K-T boundary.