GENERAL GEOLOGY

Detailed explanation-1: -Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

Detailed explanation-2: -The fossil forms that occur in the rocks, however, provide the chief means of establishing a geologic time scale, with the timing of the emergence and disappearance of widespread species from the fossil record being used to delineate the beginnings and endings of ages, epochs, periods, and other intervals.

Detailed explanation-3: -Divisions of geologic time As of April 2022 there are three formally defined eons/eonothems: the Archean, Proterozoic, and Phanerozoic. The Hadean is an informal eon/eonothem, but is commonly used. An era is the second largest geochronologic time unit and is the equivalent of a chronostratigraphic erathem.

Detailed explanation-4: -Relative time ("chronostratic")–subdivisions of the Earth’s geology in a specific order based upon relative age relationships (most commonly, vertical/stratigraphic position). Absolute time ("chronometric")–numerical ages in “millions of years” or some other measurement.