Law of Superposition
This principle states that younger rock layers lie above older layers.
What is the Law of Superposition?
Scientists use this method to find the actual age of certain rocks using decay of unstable elements.
What is radioactive dating?
These preserved remains help show how life and Earth changed over time.
What are fossils?
Scientists divide Earth’s history into large sections of time called this.
What is the geologic time scale?
This type of rock is most likely used in law of superposition studies because it forms in layers.
What is sedimentary rock?
This is a commonly used radioactive element for dating ancient rocks.
What is uranium?
These layered rocks help show Earth’s long history.
What are sedimentary rock layers?
Billions of years of Earth’s history are recorded in these rocks.
What are rock strata?
If a fault cuts through several layers, this tells scientists the fault is ________ than the layers.
What is younger?
The measurable breakdown of atoms over time helps geologists find this kind of age.
What is absolute age?
This principle explains that the present is key to the past — processes we see now acted the same in the past.
What is uniformitarianism?
This physical evidence shows environments of the past (like ancient oceans on mountains).
What are marine fossils on mountains?
The law of superposition helps scientists determine this type of age of rock.
What is relative age?
This law/phenomenon makes radioactive dating possible by measuring the “half life.”
What is radioactive decay?
Matching similar fossils on different continents supports this idea about Earth’s history.
What is continental drift?
Comparing rock layers from different places to find their order is called this.
What is correlation?