Guide Fossil (Noun)
Meaning
A fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found.
Classification
Nouns denoting natural objects (not man-made).
Examples
- The trilobite fossil found in the rock layer is a reliable guide fossil for the Cambrian period.
- Ammonites are often used as guide fossils for determining the age of rocks from the Jurassic and Cretaceous periods.
- The presence of a specific species of brachiopod in the rock sample serves as a guide fossil for the Devonian period.
- Fossilized coral is a useful guide fossil for dating rocks from the Paleozoic and Mesozoic eras.
- The discovery of a guide fossil like Archaeopteryx can help paleontologists determine the age of the surrounding rock layer.