GENERAL GEOLOGY

Detailed explanation-1: -An era is made up of periods, and several eras make up an eon. The Phanerozoic eon started about 541 million years ago (mya). It is made up of the Paleozoic era (from the Greek for “oldest life"), the Mesozoic era ("middle life") and the Cainozoic era ("latest life").

Detailed explanation-2: -One Era is hundreds of millions of years in duration. Period: This is the basic unit of geologic time. A Period lasts tens of millions of years, which is the time it takes to form one type of rock system.

Detailed explanation-3: -era = A unit of time shorter than an eon but longer than a period. period = A unit of time shorter than an era but longer than epoch. epoch = A unit of time shorter than a period but longer than an age.

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. It is the geochronologic equivalent of a chronostratigraphic system.