STENO’S LAWS
This law states that in undisturbed rock layers, the oldest rocks are on the bottom.
What is the Law of Superposition?
These types of rocks usually contain fossils.
What are sedimentary rocks?
Relative dating tells scientists this, but not the exact age in years.
What is which rock is older or younger?
This term refers to the vast span of Earth’s history.
What is geologic time?
How many major mass extinctions have occurred?
What are five?
This principle explains that sedimentary rocks are originally deposited in flat layers.
What is Original Horizontality?
According to superposition, are top layers older or younger?
What are younger layers?
In relative dating, scientists compare rocks instead of using this.
What is exact age (absolute dating)?
This is the largest division of geologic time.
What is an eon?
This extinction event is known as “The Great Dying.”
What is the Permian–Triassic extinction?
This law states that rock layers extend sideways until they thin out or are cut.
What is Lateral Continuity?
If rock layers are tilted, what does this tell scientists?
What is that something happened after deposition?
Which is older: a rock layer or an intrusion that cuts through it?
What is the rock layer?
The era known as the “Age of Dinosaurs.”
What is the Mesozoic Era?
This event wiped out the dinosaurs.
What is the Cretaceous–Paleogene extinction?
This principle explains why a fault is younger than the rock layers it cuts through.
What is Cross-Cutting Relationships?
What do rock layers act as a record of?
What is Earth’s history?
What does relative dating NOT tell scientists?
What is the exact age in years?
The era in which mammals dominate and humans appear.
What is the Cenozoic Era?
Name one major cause of mass extinctions.
What is climate change / volcanic activity / asteroid impact?
This principle states that rock fragments found inside another rock are older than the surrounding rock.
What is the Principle of Inclusions?
What process often removes parts of rock layers over time?
What is erosion?
Which two things do scientists know and not know with relative dating?
What is which rock is older, but not how old it is?
These divisions of geologic time go from largest to smallest.
What are eon, era, period, epoch?
Mass extinctions reshaped Earth’s ecosystems by doing this.
What is eliminating large numbers of species?