Relative Age
Fossils
Absolute Age
Geologic Time Scale
More Geologic Time Scale
100
This is the age of a rock as compared to another rock.
What is Relative Age?
100
These are any remains, trace, or imprint of a living thing that has been preserved in Earth's crust.
What are fossils?
100
The assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in the pas
What is uniformitarianism?
100
Which formed first: rock layers or faults?
What are rock layers?
100
This is how the Dinosaurs became extinct.
What are asteroid impacts and volcanic eruptions?
200
This idea states that lower layers of rocks in a series are older and upper layers of rocks are younger.
What is superposition?
200
Most often, fossils are formed in this.
What is sedimentary rock?
200
You can infer that these are younger than any rocks they cut across.
What are faults?
200
This is how long ago the Earth was formed.
What is 4.6 Billion Years ago?
200
In the illustration, why is this place in Utah and Arizona called the Grand Staircase?
What are rocks that form a step-like pattern similar to a gigantic staircase?
300
This is when magma hardens in rock layers.
What is an intrusion?
300
Specific fossils are the remains of living things that were widespread but only lived for a short period in Earth's history.
What are index fossils?
300
What causes an organism to appear then disappear in the fossil reocrd?
What is environmental or climate change?
300
These are the first living organisms.
What is bacteria?
300
How is unconformity different from other types of disconformity?
Nonconformities occur between older igneous or metamorphic rock and a younger sedimentary rock layer deposited above it?
400
Sometimes telling the relative age of rocks is not as simple as looking at the layers because the crust can do this over the course of time.
What is move, tilt, fold, crack, overturn? (any of these answers works)
400
Based on the model, what must have occurred between layers A and B? 
What is erosion?
400
Based on the illustration, Dinosaurs in the top layer, are considered this.
What are complex organisms?
400
Their shells indicate whether the climate was cooler or warmer when the shells formed.
What are foraminiferans?
400
A series of colorful cliffs stretching between Bryce Canyon and the Grand Canyon.
What is the Grand Staircase?
500
Most fossils form in this type of rock.
What is sedimentary rock?
500
To determine the relative order of geologic events based on patterns of rock layering in built-up rock sediments.
What is interpreted as the ages of the layers in comparison to others?
500
This is the other method of determining an age of a fossil that is not exact.
What is relative age?
500
The law of superposition helps geologists to determine what?
What is the relative age of rock layers?
500
A gap in the sequence of sedimentary rock layers caused by erosion..
What is unconformity?