Definition, Meaning & Synonyms

index-fossil

noun

/ˈɪndɛks ˈfɒsəl/

Definition

An index fossil is a fossil that is used to define and identify a particular time period in the geological timescale.

Examples

The trilobite is a classic example of an index fossil used in the Cambrian period.
In geology, finding an index fossil can help determine the relative age of a rock layer.
Some index fossils are widely distributed and existed for a short duration, making them perfect for dating rock layers.

Meaning

Index fossils are significant because they help geologists and paleontologists to correlate the age of the rocks in which they are found, allowing scientists to date other fossils and rock layers.