EVERYDAY SCIENCE

Detailed explanation-1: -A Period lasts tens of millions of years, which is the time it takes to form one type of rock system. Epoch: This is the smallest unit of geologic time. An Epoch lasts several million years.

Detailed explanation-2: -An epoch is the second smallest geochronologic unit, between a period and an age. It is the equivalent of a chronostratigraphic series. As of April 2022 there are currently 37 defined and one informal epochs/series.

Detailed explanation-3: -The eras are the four major divisions of the geological time scale: Precambrian, Paleozoic, Mesozoic, and Cenozoic.

Detailed explanation-4: -The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called-in descending order of duration-eons, eras, periods, epochs, and ages.

Detailed explanation-5: -Epochs and Ages Periods of geological time are subdivided into epochs. In turn, epochs are divided into even narrower units of time called ages. For the sake of simplicity, only the epochs of the Paleogene, Neogene, and Quaternary periods are shown on the time scale at the top of this page.