Our Changing Planet

Front

What is radioactive dating?

Back

A method used to determine the absolute age of igneous and metamorphic rocks by measuring the decay of radioactive isotopes.

Front

Why do continents float at a higher elevation than the ocean floor?

Back

Because continental crust is less dense than oceanic crust.

Front

What is an index fossil?

Back

A fossil that is used to define and identify a particular time period in the geologic time scale.

Front

What does the Mesozoic represent in the geologic time scale?

Back

An era that is known for the age of dinosaurs.

Front

What type of crust is less dense and thicker?

Back

Continental crust.

Front

What is the significance of trilobite fossils?

Back

They can be used to determine the age of the rock layer in which they are found.

Front

What is the difference between oceanic and continental crust?

Back

Oceanic crust is denser and thinner, while continental crust is less dense and thicker.

Front

What is the geologic time scale?

Back

A system of chronological dating that relates geological strata to time.

Front

What are the main types of rocks?

Back

Igneous, sedimentary, and metamorphic.

Front

What is the process of fossilization?

Back

The process by which organic material is preserved in sedimentary rock.