GEOLOGY

Detailed explanation-1: -The Precambrian consists of Earth’s first three eons, extending from approximately 4.6 billion to 635 million years ago. The Precambrian eons are the Proterozoic (the last eon), the Archean, and the Hadean (the earliest point of Earth’s history). The Precambrian covers 88% of Earth’s history.

Detailed explanation-2: -Precambrian (Informal-4.6 billion years ago to 541 million years ago) Precambrian is the informal name for the first 4 billion years, or 88 percent, of Earth’s history. It includes the Proterozoic and Archeon Eons.

Detailed explanation-3: -The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth’s history, set before the current Phanerozoic Eon.

Detailed explanation-4: -The Precambrian represents more than 80 percent of the total geologic record. All life-forms were long assumed to have originated in the Cambrian, and therefore all earlier rocks were grouped together into the Precambrian.

Detailed explanation-5: -Hadean Eon, informal division of Precambrian time occurring between about 4.6 billion and about 4.0 billion years ago.