Principles
What is the correct order of geologic time units?
What is Eon, Era, Period, Epoch?
Older rocks contained within newer rocks are called....
What are inclusions?
Enables scientists to determine numerical age.
Absolute-age dating.
Rock or sediment layer that serves as a time marker.
What is a key bed?
Preserved remains or traces of ancient life
Fossils
Older layers of rock are found below younger layers.
What is the Law of Superposition?
Which eon covers the greatest span of Earth's history?
What is the Precambrian?
Used to determine absolute age.
Radioactive isotopes.
Forms when titled or slanted sedimentary rock is later covered by more sediment.
What is angular unconformity?
_______ fossils can provide information about how organisms moved, rested, burrowed, etc.
Trace
Layers of sediment are originally deposited flat and horizontal.
What is the Law of Original Horizontality?
What are three types of unconformities?
What are angular unconformities, nonconformities, and disconformities?
Amount of time it takes for one half the amount of the original isotope to decay.
Half-life
Allows scientists to place rock layers and events in order using no numbers.
What is relative-age dating?
Name an example of a trace fossil
footprint, worm trail, burrows
Rock layers extend outward until something stops them.
What is the Law of Lateral Continuity?
A graphical representation of Earth's history from its origin is?
What is geological time scale?
Technique by which scientists use the ratio of parent atoms to daughter atoms to determine absolute age.
Radiometric dating.
States that geologic processes happening today have happened since the beginning of time.
Uniformitarianism
Name an example of an index fossil
Trilobite
A fault or intrusion is younger than the layers it cuts through.
What is the Law of Cross-cutting?
Name three Eras.
Paleozoic, Mesozoic, Cenozoic
The science of using tree rings to determine age.
Dendrochronology.
There are 5 of these.
Principles of Relative-age dating.
The remains of plants and animals that have been altered very little.
Original preservation