Geological time
Geological time refers to the vast timeline of Earth's history that spans over 4.5 billion years. This time scale is organized into hierarchical units, such as eons and eras, that each include significant geological and biological events. Understanding these divisions helps scientists contextualize the evolution of life and the dynamic changes the planet has undergone over time.
Use this page to revise the following concepts within geological time:
Divisions of Geological Time
The largest divisions of geological time are eons, and these are then subdivided into eras. Eras are broken down into periods, and periods are subdivided into epochs. Each of these units represents a specific length of time during which major geological and evolutionary changes occurred. Investigate these divisions of geological time by interacting with the following diagram.
Stratigraphy
Stratigraphy is the study of rock layers (strata) and their sequence, offering vital insights into Earth's geological history. By examining the layers of sedimentary rock, geologists can determine the relative ages of different rock formations and the fossils they contain. Stratigraphy plays a crucial role in understanding geological time, as it reveals the chronological order of events that have shaped the planet over millions of years. The vertical arrangement of strata allows scientists to map out the history of Earth, identifying key events such as mass extinctions and the emergence of new species .
