Chemostratigraphy can also be the basis for defining a member, bed or subdivision of a geologic unit.

The Caloris group is a set of geologic units on Mercury.

The polar layered deposits are some of the youngest geologic units on Mars.

Yardangs on Mars demonstrate that much of the eolian erosion is recent since they are sculpted in young geologic units.

Some important concepts: A formation is a formally named and defined geologic unit with unique characteristics.

The geologic unit is notorious as a source of radon gas related to its high uranium content, released by radioactive decay.

It occurs in masses within the third geologic unit of the kuroko type deposits within the mine.

The Apache Group in descending order from youngest to oldest geologic units:

On the other hand, large regions of the western hemisphere are taken up by dark geologic units thought to be surface basalts.

At least two geologic units compose the edifice.