Relative Dating
Absolute Dating
Fossils
Disturbances
Miscellaneous
100
Determining whether an object or event is older or younger than other objects or events is called....
Relative Dating
100
Determining the approximate age of a rock, fossil, or event.
Absolute Dating
100
A fossil that appears for a short period of time in specific areas.
An Index Fossil
100
This rock diagram has a line running through with arrows pointing in the direction of rock movement. What does the line represent?
A Fault
100
What kind of rock is formed in layers?
Sedimentary
200
Younger rock is found ________ older rock.
Above
200
Which method would result in an absolute date for a rock that formed billions of years ago?
Radioactive Dating
200
The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock
Fossil
200
When pressure pushes rocks together, this process begins to disturb rock.
Folding
200
A break or crack in the Earth's crust where rock can move. Rock "slips" down and disrupts the layers
A Fault
300
A missing layer from the geologic record is called...
An Unconformity
300
The time needed for half of a sample of a radioactive substance to undergo.
What is Half Life
300
If a fossil is found in a particular rock layer, what can we say about both the fossil and the rock layer?
The formed at the same time.
300
An intrusion or fault must be ______________ that the rock that it cuts through.
Younger
300
Rock layers used to learn about Earth's history
This is called a Geologic column
400
The Law that states that younger rock is found above older rock as long as the rock layers have not been disturbed.
The Law of Superposition
400
Process that occurs when the an atom goes through a half life and a new element is formed, giving off energy and an alpha particle.
Radioactive Decay
400
Helps them determine the date of the rock and the fossil
How does index fossils help geologist
400
Why might there be a horizontal gap in the layers of sedimentary rock?
Because of weathering and erosion. Over a very long period of time, water flowing across the surface of the rock can break the rock down into sediment and carry it away, leaving a gap.
400
When igneous rock that forms when magma is injected into rock and then cools and becomes hard, it is called...
An intrusion (keyword: Magma = inside Earth)
500
In this rock layer diagram there are two unconformities, a fault at E and an intrusion at D. Which unconformity occurred first? How do you know?
Intrusion D occurred first because the instrusion has been moved by the fault.
500
Why are isotopes with short half-lives not useful for dating very old rocks?
Not enough of the parent isotope remains to measure accurately
500
Many mass extinctions took place in the Permian and the Cretaceous periods. Scientists use different methods to determine the causes of the mass extinctions and to find out about the species that died. What is one method scientists use to learn about mass extinctions?
Studying rock layers and the fossil record
500
What are the five ways that rocks are disturbed?
Folding, Faulting, Tilting, Intrusion, Unconformities
500
Explain the difference between absolute and relative dating? Why might Scientist need to use both methods to determine the age of a rock?
Relative dating is used to determine the age of a rock layer compared to the layers around it. It gives the sequence in which events occurred in Earth’s history. Absolute dating is used to determine the age of a rock or event in years.
Scientists may not be able to determine the absolute age of some rocks.