Rock Layers
Half-Life
Geologic Time
Random Stuff
Vocabulary

100

Intrusions are always (younger/older) than the layers around them.
What is younger?

100

If you start with 500 atoms of an element, how many remain after 1 half-life?
What is 250 atoms?

100

Cenozoic, Paleozoic, and Mesozoic are _________.
What are Eras?

100

A foot print of an animal is an example of a (trace/index) fossil?
What is trace?

100

Hardened remains of once living things.
What is fossil?

200

The oldest layer is found at the _______.
What is the bottom?

200

If you start with 500 atoms of an element, how many remain after 2 half-lives?
What is 125 atoms?

200

The Jurassic Period is during which Era?
What is Mesozoic?

200

Fossils are not found in which type of rock? Sedimentary, metamorphic, or igneous?
What is igneous?

200

The dieing out of a species.
What is extinct?

300

When a fault is found in a rock layer sample, what should you do first to decide which layer is the oldest?
What is line up the layers?

300

After 2 half-lives, you have 1000 atoms. How many did you start with?
What is 4000 atoms? (1000x2)= 2000 (2000x2) = 4000

300

If something died out 310 million years ago, what epoch did it die out during?
What is Pennsylvanian?

300

An element that is able to decay is referred to as?
What is radioactive?

300

The age of something compared to another item.
What is relative age?

400

If you see a rock layer with a sea shell, what can you infer about that area?
What is it was once under water/part of the sea?

400

The half-life of element x is 5000 years. If you start with 60 atoms of element x, how long would it take to end up with 15 atoms?
What is 15000 years?

400

What is the oldest Period?
What is Precambrian?

400

The Law of Superposition states that __________ rock layers are found above _________ ones.
What is younger--older? (must be in that order)

400

A fossil that is used as a comparison to other fossils and helps determine geologic age.
What is index fossil?

500

If rock layer x is below rock layer y, which is older?
What is rock layer x?

500

If the half-life of element Y is 200 years. How long would it take for 4 half-lives?
What is 800 years.

500

What Epoch are we currently in?
What is Holocene?

500

What is older, the first fish or the formation of the Great Lakes?
What is the first fish?

500

Rock layer that forms on the surface and is younger than the layers around it.
What is extrusion?