History of Earth Flashcard

Front

Index fossil

Back

A fossil used to determine the relative age of rock layers.

Front

Law of Superposition

Back

The principle that younger rock layers are deposited on top of older ones.

Front

What is radioactive decay used for?

Back

To determine the absolute age of rocks.

Front

What is the geologic time scale?

Back

A record of geologic events and the evolution of life.

Front

What is the difference between an era and a period?

Back

An era is longer than a period.

Front

What is a fossil?

Back

The remains or impression of a prehistoric organism preserved in rock.

Front

Half-life

Back

The time it takes for half of a radioactive substance to decay.

Front

Which era comes after the Paleozoic Era?

Back

Mesozoic Era

Front

What is an unconformity in geology?

Back

A gap in the geological record.

Front

What is folding in geology?

Back

The bending of rock layers due to stress.