Copper is found in all geologic periods. It's a very abundant element in the Earth's crust and has been forming in various geological processes for billions of years.

Here's a more detailed explanation:

* Formation: Copper is formed in the Earth's core and mantle through various processes, including volcanic eruptions, hydrothermal activity, and the weathering of rocks.

* Deposition: Copper deposits are formed over time, as these processes deposit copper-rich minerals in specific geological environments.

* Occurrence: Copper can be found in a wide variety of rock types, including igneous, sedimentary, and metamorphic rocks.

Therefore, while copper can be found in specific geological formations associated with particular periods, it's not limited to any one period. It exists throughout Earth's history.