Geologic Time

Question 1

Geologic Time Scale (Eons)

Answer 1

1. ) Archaen
2. ) Proterozoic
3. ) Phanerozoic

Question 2

Geologic Time Scale (Eras)

Answer 2

1. ) Paleozoic
2. ) Mesozoic
3. ) Cenozoic

Question 3

Geologic Time Scale (Period)

BROKEN UP BY ERA

Answer 3

Paleozoic

1. ) Cambrian
2. ) Ordovician
3. ) Silurian
4. ) Devonian
5. ) Carboniferous
6. ) Permian

Mesozoic

7. ) Triassic
8. ) Jurassic
9. ) Cretaceous

Cenozoic

10. ) Paleogene
11. ) Neogene
12. ) Quaternary

Question 4

5 Major Mass Extinctions During the Phanerozoic Eon

Answer 4

1. ) End-Ordovician (first major extinction occurs at the end of the ordovician
2. ) Late Devonian Crisis (losing GIANT reefs resulted in a drop in taxonomic diversity)
3. ) Permo-Triassic Extinction (BIGGEST MASS EXTINCTION IN HISTORY at the end of the Paleozoic era)
4. ) End-Triassic Extinction THE GREAT DYING (big impact on marine animals; lots of land reptiles die out and don’t make it to the jurassic period)
5. ) End-Cretaceous Extinction (asteroid from space kills all the dinosaurs)
   - non-avian dinosaurs? GONE

Question 5

Phanerozoic Eon: Three Evolutionary Faunas of Marine Animals

Answer 5

Cambrian

• “Cambrian Explosion” resulted in an explosion of life (specifically marine)
• trilobites

Paleozoic
- Conoderms and inarticulate braciopods

Modern
- bony fish, mollusks, primitive crinoids

Question 6

What is an isotope?

Answer 6

an element which contains a different number of neutrons

Question 7

Betonite layers (volcanic ashes) as marker beds

Answer 7

can use crosscutting relationships and principle of superposition along with radiometric dating to determine the age of shale

Question 8

Igneous Rocks

Answer 8

zircons

Question 9

Clair Patterson; Why did he have to use meteorites?

Answer 9

• used the concept of half-life to calculate the age of the earth;
• his samples were contaminated with lead
• looked at meteorites because they maintained their unchanged, internal chemistry