Geologic time scale
The geologic time scale is a system used by scientists to categorize and study Earth's history based on significant geological and biological events. It organizes Earth's history into distinct intervals of time, each representing an era, period, or epoch.
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It organizes Earth's history into distinct intervals of time, each representing an era, period, or epoch. The time scale is divided into four major eons: the Hadean, Archean, Proterozoic, and Phanerozoic. The Phanerozoic eon is further divided into three eras: Paleozoic, Mesozoic, and Cenozoic. Within these eras, various periods and epochs further delineate Earth's history. The geologic time scale provides a framework for understanding the evolutionary history of life, changes in Earth's climate, and the formation of rock layers. Scientists use various methods, including radiometric dating, fossil records, and stratigraphy, to determine the age and sequence of events in Earth's geological history.