GENERAL GEOLOGY

Detailed explanation-1: -Eon: Two or more eras compose an Eon. This is the largest division of time, lasting hundreds of millions of years.

Detailed explanation-2: -Classifying time To make geologic time easier to comprehend, geologists divided the 4.6 billion years of Earth’s history into units of time called eons. Then they further divided the eons into two or more eras, eras into two or more periods, periods into two or more epochs, and epochs into two or more ages.

Detailed explanation-3: -Nowadays, and speaking very generally, geological time is divided first into four great chunks known as eras: Precambrian, Paleozoic (from the Greek meaning old life), Mesozoic (middle life), and Cenozoic (recent life).

Detailed explanation-4: -An era is the second largest geochronologic time unit and is the equivalent of a chronostratigraphic erathem. As of April 2022 there are currently ten defined eras/erathems. A period is a major rank below an era and above an epoch.

Detailed explanation-5: -Geologists recognize two different kinds of time: relative time and absolute age. Relative time concerns the sequence of geologic events, and absolute age measurements concern the actual age of a rock or mineral.