Geologic Time

The age of a rock given as the number of years since the rock formed.

• relative age
• half-life
• absolute age
• radioactive decay

The age of a rock compared to the ages of other rocks.

• relative age
• half-life
• absolute age
• radioactive decay

A record of the geologic events and life forms in Earth's history.

• index fossil
• half-life
• radioactive dating
• geologic time scale

Fossils of widely distributed organisms that lived during a geologically short period.

• index fossil
• half-life
• radioactive dating
• geologic time scale

One of the units of geologic time into which geologists divide eras.

• era
• geologic time scale
• period
• uncomformity

A gap in the geologic record that shows where rock layers have been lost due to erosion.

• extrusion
• unconformity
• intrusion
• law of superposition

Which of the following represents the longest time period

• Precambrian
• Paleozoic
• Mesozoic
• Cenozoic

The _________ was an era dominated by the dinosaurs

• Precambrian
• Paleozoic
• Mesozoic
• Cenozoic

Identify the Era:
called the "Age of Mammals"

• Precambrian
• Paleozoic
• Mesozoic
• Cenozoic

Identify the Era:
First forms of life appeared in this era.

• Precambrian
• Paleozoic
• Mesozoic
• Cenozoic