Chapter 4 Geologic Time - Christina Doudakis

Hey guys! Can I join you?

Yeah sure! Come right ahead and join us!

So what are you guys talking about?

Oh, Alex was explaining to me about Geologic Time.

So Geologic Time is the large amount of time taken by the geologic history of Earth? Am I right?

Yes you are right Sammy good job!

Geologic time begin at the start of Archean Eon which it was 2.5 - 4.0 bil. years ago. And it still goes on to this day.

The geologic time is known as a "calendar" for events in Earth's history.

This sounds great! But I have a question. I don't remember the Archean Eon. Can you explain it to me please?

The Archean Eon was 4.6b - 541m years ago. It was when life started forming on Earth!

Awww Via is blushing!

Via the more knowledge you get the cutter you are becoming!

Um . Aghhh, th- thank- thank you?

Now Via you need to understand some other things like "how are fossils use to date the Earth's age"?

Geologists use radiometric dating methods of certain elements like potassium as clocks to date ancient events.

Now fossils that are used to support plate tectonics are glaciers and complimentary coastlines. This fossils help as what kind of plants and animals once existed.

Next up is "Absolute Age" is the age of a geologic phenomenon measured in present Earth years.

Now "Relative Age" is the geologic age of a fossil organism, rock, geologic feature, or event.