1
Many species die off during these.
What happens during a Mass Extinction event?
An example of this kind of dating is: A geologist determines that a sample of rock on a lakebed is 37 million years old.
What is absolute dating?
These are qualities of this kind of fossil:
It is easily identifiable.
It is found abundantly.
It is geographically widespread.
What are index fossils?
This is what a scientist would most likely be trying to determine when he performs a correlation study on several rock samples from a large area.
Which rocks are the same age?
This is the era of geologic time we are currently living in.
What is the Cenozoic era?
climate change, volcanic eruptions, meteorite impacts, and movement of continents
What are some of the events that scientists believe may have been responsible for a mass extinction on earth?
Scientists generally assume that a layer of sedimentary rock that lies at an angle has been shifted by this in the past.
What are tectonic forces?
This is what scientists call an interrupting boundary between layers of sedimentary rock.
What is an unconformity in rock?
This is what happens to unstable radioactive isotopes over time.
What is decay to form more stable isotopes at a predictable rate?
This word describes the shortest period of geologic time.
What is an age.