GEOLOGY

Detailed explanation-1: -The primarily defined divisions of time are eons, the Hadean, the Archean, the Proterozoic and the Phanerozoic . The first three of these can be referred to collectively as the Precambrian supereon. Each eon is subsequently divided into eras, which in turn are divided into periods, which are further divided into epochs.

Detailed explanation-2: -The geologic time scale is divided into (from longest to shortest): eons, eras, periods, epochs and ages.

Detailed explanation-3: -The geologic time scale was developed after scientists observed changes in the fossils going from oldest to youngest sedimentary rocks. They used relative dating to divide Earth’s past in several chunks of time when similar organisms were on Earth.

Detailed explanation-4: -The scale is further broken down into time periods which are explained below. Eon: Two or more eras compose an Eon. This is the largest division of time, lasting hundreds of millions of years.

Detailed explanation-5: -The geological time scale is based on the the geological rock record, which includes erosion, mountain building and other geological events.