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Ch. 4 Vocab

Fossil A trace or the remains of a once-living thing from long ago.
Original Remains A fossil that is the actual body or body parts of an organism.
Ice Core A tubular sample that shows the layers of snow and ice that have built up over the years.
Relative Age The age of an event or object in relation to other events or objects.
Index Fossil A fossil of an organism that was common, lived in many areas, and existed only during a certain span of time. Index fossils are used to help determine the age of rock layers.
Absolute Age The actual age in years of an event or object.
Half-Life The length of time it takes for half of the atoms in a sample of radioactive element to change from an unstable form into another form.
Uniformitarianism A theory stating that the processes shaping Earth today, such as erosion and deposition, also shaped Earth in the past, and that these processes cause large changes over geologic time.
Geological Time Scale The summary of Earth's history, divided into intervals of time defined by major events or changes on Earth.
Created by: Tee-Ball Champ