Earth's History

A principle that geologic processes that occurred in the past can be explained by current geologic processes.

Younger rocks lie above older rocks, if layers are left undisturbed.

Faults or intrusions are younger than any layer of rock they cut through.

The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock.

All fossils discovered on Earth.

The weather conditions in an area over a long period of time.

A long cylinder of ice obtained from drilling through ice caps or ice sheets; used to study past climates.

Any method of determining whether an event or object is older or younger than other events or objects.

Any method of measuring the age of an event or object in years.

A method of determining the absolute age of an object by comparing the amount of parent isotope vs. daughter isotope and using half-life.