ZT-Geology: Younger Dryas

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Younger Dryas

1.What is the lecture mainly about?

  • A. To illustrate similarities between two periods of climate change
  • B. To examine theories about the extinction of large North American mammals
  • C. To describe how scientists verify occurrences of meteor impacts on Earth
  • D. To present a new explanation for the cause of the end of the last ice age

2. What is the professor’s opinion of the claim that cooling during the Younger Dryas caused a major extinction?

  • A. It will probably be proven correct by future research
  • B. It has been strongly contradicted by recent soil-sample analysis
  • C. It seems unlikely in view of what is known about similar climate changes
  • D. It is based on a misinterpretation of evidence collected in North Americans

3. Why does the professor mention a meteor that struck Earth during the time of the dinosaurs?

  • A. To imply that that meteor impact also affects other large animals in North America
  • B. To point out that Earth was often struck by meteors in the past
  • C. To explain why scientists hypothesize that a similar impact could have caused a later extinction event
  • D. To challenge a commonly accepted claim about dinosaur extinction

4. According to the professor, what is the major significance of the Younger Dryas Boundary?

  • A. It provides proof of a sudden climate change.
  • B. It lines the inside of a 13,000-year-old impact crater.
  • C. It contains valuable information on about the composition of meteors.
  • D. It marks the disappearance of large mammal species.

5.The professor mentions that a new group of researchers collected samples from a Younger Dryas Boundary site. How did those researchers explain the high concentration of magnetic particles in the samples?

  • A. The Younger Dryas Boundary is especially thick at that site.
  • B. The particles were carried to the site by flowing water.
  • C. A meteor caused a high concentration of the particles at the site.
  • D. Old roofing material had been buried at the site.

6.What opinion does the professor express when he discusses nano-diamonds?

  • A. Their presence is not strong proof of a meteor impact
  • B. They indicate that a geological sample has been contaminated
  • C. Researchers should get a better understanding of their origin
  • D. Researchers should focus on magnetic particles instead of nano-diamonds
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