Unit Six - Geologic Time - Relative Dating

Question 1

What is Uniformitarianism?

Answer 1

The idea that forces working on our earth NOW worked on our planet in the PAST

Question 2

What is Relative Dating?

Answer 2

Determination of the age of a rock or event in relation to ages of other rocks and events

Question 3

What is the Principle of Superposition?

Answer 3

Idea that the bottom layer is the oldest, and the layers above are younger.

Question 4

What is Original Horizontality?

Answer 4

Rocks are deposited in parallel layers

Question 5

What are extrusions?

Answer 5

Molten rock flows onto the surface

Question 6

What are intrusions? (3)

Answer 6

1. An exception to the principle of superposition
2. Molten rock squeezes into preexisting rock layers
3. It is younger

Question 7

What is contact metamorphism?

Answer 7

Preexisting rocks change due to an intrusion

Question 8

What are faults?

Answer 8

A crack in the bedrock where movement has occured

(Younger than the rocks that they crosscut)

Question 9

What are folds?

Answer 9

Thrusting rock layers cause preexisting rock layers to overturn.

Question 10

Definition of Index Fossils (3)

Answer 10

1. Remains or evidence
2. Of former living things
3. Used to identify geological periods

Question 11

What are the two factors needed for fossils to be considered index fossils?

Answer 11

1. The organism has to exist over a large geographic area
2. The organism existed over a short time

Question 12

Definition of Geologic Time Markers

Answer 12

Large deposits that represent a specific date