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.
All life-forms were long assumed to have originated in the Cambrian, and therefore all earlier rocks were grouped together into the Precambrian. Although many varied forms of life evolved and were preserved extensively as fossil remains in Cambrian sedimentary rocks, detailed mapping and examination of Precambrian rocks on most continents have revealed that additional primitive life-forms existed as early as about 3.48 billion years ago.