Earth History Review

Front

What is the oldest rock layer in a geological diagram?

Back

The oldest rock layer is typically found at the bottom of the diagram.

Front

How many half-lives does it take for a radioactive sample to decay to 25% of its original amount?

Back

2 half-lives.

Front

How do scientists obtain ice cores?

Back

They drill them out of the ground of cold areas.

Front

What is a fault in geology?

Back

A fault is a fracture in the Earth's crust along which movement has occurred.

Front

What does the theory of continental drift state?

Back

The continents were once joined in a super-continent and have moved over time.

Front

What is an intrusion in geology?

Back

An intrusion is a body of igneous rock that forms when magma cools and solidifies within the Earth's crust.

Front

What is an unconformity?

Back

An unconformity is a surface that represents a gap in the geological record, where rock layers are missing.

Front

What is the principle of superposition?

Back

In undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest are at the top.

Front

What is radiometric dating?

Back

Radiometric dating is a method used to date materials by comparing the abundance of a radioactive isotope to its decay products.

Front

What are ice cores used for?

Back

Ice cores are used to study past climate conditions and atmospheric composition.