Geologic Time

Front

What is Geologic Time?

Back

Geologic Time is the timeline of Earth's history, divided into eons, eras, periods, and epochs, used to understand the age and development of the Earth and its life forms.

Front

What is the Law of Superposition?

Back

The Law of Superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

Front

What is a half-life?

Back

A half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

What are intrusive rocks?

Back

Intrusive rocks are formed from magma that cools and solidifies beneath the Earth's surface.

Front

What is sedimentation?

Back

Sedimentation is the process by which particles settle out of a fluid, forming layers of sediment.

Front

What is the significance of fossils in geology?

Back

Fossils provide evidence of past life and can help determine the relative ages of rock layers.

Front

What is an eon?

Back

An eon is the largest division of geologic time, lasting hundreds of millions to billions of years.

Front

What is an era?

Back

An era is a subdivision of an eon, lasting tens to hundreds of millions of years, characterized by significant geological or biological events.

Front

What is a period in geologic time?

Back

A period is a subdivision of an era, lasting millions of years, marked by specific events in Earth's history.

Front

What is the difference between relative age and absolute age?

Back

Relative age is the age of a rock or fossil in comparison to other rocks or fossils, while absolute age is the actual age in years.