Dr. Pamela Gore Georgia Perimeter College Objectives Reproduce the geological time scale with eras and periods. Identify the time frame of the Precambrian, Paleozoic, Mesozoic, and Cenozoic Eras. The scientifically-accepted age of the Earth is about 4.6 billion years old. In order to describe the events of Earth history, the time is divided into various time invervals called Eons, Eras, Periods and Epochs.
Eons are the largest divisions of the time scale.
No rock record. This is the time of the origin of the Earth. Earth was mostly hot molten rock at that time. The Hadean, Archean, and Proterozoic are part of what is informally called the Precambrian , a name given to the age of all of the rocks that are older than the Cambrian Period. Phanerozoic Eon - from about 544 million years to the present.