Geologic History Vocab

Front

Process that puts an actual time or date on an object or event.

Back

absolute dating

Front

The matching of rock units in one area to rock units in another area.

Back

correlation

Front

The time it takes for 50% of the original radioactive isotope to decay.

Back

half-life

Front

a fossil that can be used to correlate rock units

Back

index fossil

Front

The process of putting events into a sequence such as youngest to oldest.

Back

relative dating

Front

A missing rock unit in a geological sequence that represents a period of erosion.

Back

unconformity

Front

The present is the key to the past

Back

uniformitarianism

Front

A summary of geologic events preserved in the fossil record

Back

geologic time scale