Not that weâd expect less after the cliffhanger last season. If you havenât yet watched the September 23rd premiere of Chicago Fire, and somehow have managed not to find out who died, donât keep reading. If you have, please join me in my misery.
The Precambrian Super-Eon lasted from the formation of Earth 4,567 million years ago until the start of the Pharerozoic Eon 542 million years ago. It lasted 4.025 billion years. 90% of Earth's history.
First, a few words about the Precambrian, an informal name for the vast expanse of time prior to the Phanerozoic Eon (which includes the Paleozoic, Mesozoic, and Cenozoic Eras). The Earth formed. It then took nearly four thousand million years before the first animals would leave their traces on the planet.