Age of Rock and Geologic Time

The principle which states rock layers become younger as you near the surface is called the

• Law of Conservation

• Law of Superstition

• Law of Superposition

• Law of Sedimentary Rock

Describe relative age

• A rock layer's age compared to those around it

• The number of years since a rock formed

• The number of years since a rock was last weathered

• A rock layer's birthday

Which two conditions describe an index fossil? (choose both that are correct)

• Widely Distributed

• Only lived for short period of time

• Easily seen by geologists

• Widely Studied

Occurs when atoms of an unstable element break down to form atoms of another element

• Erosion

• Index Fossils

• Radioactive Decay

• Law of Superposition

Fossils which help scientists date the rock layers in which they are found are

• Mold and Casts

• Dinosaur Fossils

• Impossible to Find

• Index Fossils

All of the following give clues to Earth's geologic evolution except

• Ice Cores

• Rock Samples

• Water Samples

• Fossils

Radioactive Dating assist in geologists in finding the __________________ age of rocks.

• Relative

• Absolute

Fossils provide what type of evidence?

• Evidence of past organisms activities

• How organisms have changed over time

• How Earth has changed over time

• All are correct

Intrusions and extrusions are formed by what type of rock?

• Igneous

• Sedimentary

• Metamorphic

• All are correct

Describe the difference between an intrusion and an extrusions

• Intrusions occur on the surface, extrusions beneath the surface

• Extrusions occur on the surface, intrusions beneath the surface