Our best hypothesis about the formation of the Moon is that chunks of the Earth's mantle broke off during a collision in the early days of the solar system and coalesced into a satellite in orbit around their former home.

At the moment of the Moon's formation, the rocks on Earth and the rocks on the Moon would have been of exactly the same age.

Since then, both the Earth and the Moon have undergone geological processes (such as volcanism) that have created new rocks and altered surface features. The newest rocks on Earth and the Moon, presently, are therefore those most recently created by volcanic activity. In fact, because the Earth has had such a tumultuous history of surface evolution, its entire surface layer has been periodically renewed and reformed.

Is volcanic activity ongoing on Earth, or has it ceased?

Is volcanic activity ongoing on the Moon, or has it ceased?