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Geological Time Scale

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Geological Time Scale: Divisions and Chronology

The geological time scale is a scientific framework developed and refined by the international scientific community, specifically by geologists, paleontologists, and stratigraphers. It is not attributed to any single society but rather represents a collective effort by scientists from around the world. The International Commission on Stratigraphy (ICS), a scientific organization affiliated with the International Union of Geological Sciences (IUGS), plays a significant role in establishing and maintaining the geological time scale. The ICS coordinates with experts in the field to define and update the divisions and boundaries of the time scale based on scientific evidence and consensus.



The geological time scale is a framework used to divide Earth's history into different time intervals based on significant geological and biological events. Here is a concise overview of the major divisions in the geological time scale, from largest to smallest:

Eon: 

The largest division of time. The current eon is the Phanerozoic, which represents the time from the present to about 541 million years ago.

Era: 

The second-largest division. The Phanerozoic eon is divided into three eras:Paleozoic: This era spans from about 541 to 252 million years ago and includes the rise of marine life, the colonization of land, and the formation of early forests.
Mesozoic: This era spans from about 252 to 66 million years ago and is often referred to as the "Age of Dinosaurs."
Cenozoic: This era spans from about 66 million years ago to the present and includes the diversification of mammals and the rise of humans.

Period: 

The third level of division. Each era is further divided into several periods. For example, the Cenozoic era includes the Paleogene, Neogene, and Quaternary periods.

Epoch: 

The fourth level of division. Each period is further divided into epochs. For example, the Quaternary period includes the Pleistocene and Holocene epochs.

Age: 

The smallest and most detailed level of division. Ages represent shorter intervals within epochs and are often defined by specific geological events or significant changes in the fossil record.

It's important to note that the geological time scale is a dynamic framework that is continuously refined and updated as new discoveries and research emerge.

Earth's history unfolds in the layers of its rocks, and the geological time scale provides a roadmap, revealing the grand narrative of our planet's ancient past.

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