Question

what geologic period lasted for almost 7/8 of earth’s history?

Answer 1

The geological division that lasted for just over 7/8ths of the Earth's history is the Precambrian Super-Eon. It started 4576.2 million years ago with the formation of Earth and ended 542 million years ago at the start of the Cambrian Period. It is made up of the Hadean, Archean and Proterozoic Eons. Although the super-eon is widely recognised as a time division this is only an unofficial term. The ICS prefer to use the Eon when describing the time before the Cambrian.