Geologic Time

Question 1

Eon

Answer 1

The largest division of geologic time, lasting 500 million years or more.

Question 2

Era

Answer 2

The second largest division of geologic time, lasting at least 65 million years or more. They describe when important life evolved or major extinction events occurred and are divisions of eons.

Question 3

Period

Answer 3

The third largest division of geologic time, lasting from 2.6 million years to 100 million years. They describe more specific events like mountain building and plate movements and are subdivisions of eras.

Question 4

Epoch

Answer 4

Detailed segments of time that are subdivisions of periods. They represent specific events relative to a much shorter time frame.

Question 5

Age

Answer 5

Represents the shortest geologic time frame and are subdivisions of epochs.

Question 6

Which eras are in the Phanerozoic Eon?

Answer 6

Cenozoic, Mesozoic, and Paleozoic

Question 7

Which eras are in the Precambrian Eon?

Answer 7

Proterozoic, Archean, and Hadean

Question 8

How old is the Earth?

Answer 8

4.56 billion years

Question 9

What periods are in the Cenozoic Era?

Answer 9

Quarternary, Neogene, and Paleogene

Question 10

What periods are in the Mesozoic Era?

Answer 10

Cretaceous, Jurassic, Triassic

Question 11

What periods are in the Paleozoic Era?

Answer 11

Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian