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The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks).
This list is divided first into the geologic eras of the Phanerozoic (the Cenozoic, the Mesozoic, and the Paleozoic) and then into the geologic periods of each era. Each period is marked below the era bar on top of its subdivided epochs and stages.
The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, the most recent period is expanded in the fourth timeline, and the most ...
Geologic time is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day. Radiometric dating measures the steady decay of radioactive elements in an object to determine its age. It is used to calculate dates for the older part of ...
The history of the Earth can be organized chronologically according to the geologic time scale, which is split into intervals based on stratigraphic analysis. [2] [21] The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space ...
Geologic time shown in a diagram called a geological clock, showing the relative lengths of the eons of Earth's history and noting major events The geological history of Earth follows the major geological events in Earth's past based on the geologic time scale , a system of chronological measurement based on the study of the planet's rock ...
Geologic Time – Period prior to humans. 4.6 billion to 3 million years ago. (See "prehistoric periods" for more detail into this.) Primatomorphid Era – Period prior to the existence of Primatomorpha; Simian Era – Period prior to the existence of Simiiformes; Hominoid Era – Period prior to the existence of Hominoidea
At this time, it was incorrectly presumed that the Yarmouth Paleosol formed during a single interglacial stage, which separated a younger glacial stage, the Illinoian Glaciation represented by the sediments of the Glasford Formation in Illinois, and the glacial deposits of an older glacial stage called the "Kansan Glaciation".