The Relative Age of Rocks

The number of years that have passed since the rock formed is the rock's

• relative age
• law of superposition
• absolute age
• index fossil

The age of a rock compared to the ages of other rocks is the rock's

• absolute age
• geologic age
• sedimentary age
• relative age

A formation of igneous rock on Earth's surface is known as 

• a gap
• an intrusion
• a fault
• an extrusion

A break in Earth's crust is called

• an intrusion
• a fault
• a layer
• an index fossil

Geologists use the law of _________ to determine the relative ages of sedimentary rock layers.

• geology
• superposition

A mass of igneous rock below the Earth's surface is called a __________/

• intrusion
• extrusion

Because of ___________, most of the geologic record of sedimentary rock layers has been lost. 

• unconformity
• erosion

A gap in the geologic record is known as a(n)_______________.

• unconformity
• intrusion

The position in which rock layers appear can be changed by gaps in the geologic record and by ______________.

• faults
• folding

According to the law of __________, in horizontal sedimentary rock layers the oldest layer is at the bottom and the youngest layer is at the top. 

• superposition
• index fossil