What occurs first?

Answer 1

The first geological era is called the Eoarchean, and it began approximately 4000 million years ago (or 4000 Ma) and lasted 400 million years until 3600 Ma. The date of its inception is subject to some scientific debate. The name comes from Greek words meaning "ancient dawn."

It is the first era of the first eon, a broader time frame called the Archean. The Eoarchean occurred early in Precambrian times but began about 500-600 million years after the formation of planet earth. During the Eoarchean era rocks were formed that are still to be found on earth today. The first oceans likely already existed, and some evidence exists for the first supercontintent. The heaviest of the meteorite bombardment ended during the Eoarchean, and the era may have seen the rise of the earliest life forms, though this is the subject of ongoing research

The Precambrian is a period of time called a supereon. It lasted for most of the history of the earth and is divided into several geological eras, the first of which is the Eoarchean.