Geologic Time Line

This is the model of Earth's history from its origin 4.6 billion years ago to the present.

• geologic time scale

• key beds

• index fossils

• major geologic events

Tags

NGSS.MS-ESS1-4

These are the longest units of geologic time.

• eons

• era

• period

• epoch

Tags

NGSS.MS-ESS1-4

This is the present eon. It began about 541 million years ago.

• Phanerozoic

• Cenozoic

• Quarternary

• Holocene

Tags

NGSS.MS-ESS1-4

These are the second longest units of geologic time. Eons are divided up into these.

• eras

• periods

• epochs

• unconformities

Tags

NGSS.MS-ESS1-4

This is the present era. It began about 66 million years ago.

• Cenozoic

• Phanerozoic

• Quarternary

• Holocene

Tags

NGSS.MS-ESS1-4

These are the third longest units of geologic time. Eras are divided up into these.

• periods

• eons

• epochs

• unconformities

Tags

NGSS.MS-ESS1-4

This is the present period. It began about 2.6 million years ago.

• Quarternary

• Phanerozoic

• Cenozoic

• Holocene

Tags

NGSS.MS-ESS1-4

These are the smallest main unit of geologic time. Periods are broken up into these.

• epochs

• eons

• eras

• unconformities

This is the present epoch. It began about 11,600 years ago.

• Holocene

• Phanerozoic

• Cenozoic

• Quarternary

This is a surface where the rock has eroded away, producing a break, or gap, in the rock record.

• unfonformity

• inconsistancy

• uniformity

• correlation