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[[File:Geologic_clock.jpg|center|frame]]

[[File:Geologic_clock.jpg|center|frame]]

The '''geologic time scale''' provides a [[system]] of chronologic [[measure]]ment relating [http://en.wikipedia.org/wiki/Stratigraphy stratigraphy] to [[time]] that is used by geologists, paleontologists and other [[Earth Science|earth scientists]] to describe the [[timing]] and [[relationships]] between [[events]] that have occurred during the [http://nordan.daynal.org/wiki/index.php?title=The_Urantia_Text_-_Contents#Part_III._The_History_of_Urantia history of the Earth][http://en.wikipedia.org/wiki/History_of_the_Earth]. The table of geologic time spans presented here agrees with the dates and [[Names|nomenclature]] proposed by the [http://en.wikipedia.org/wiki/International_Commission_on_Stratigraphy International Commission on Stratigraphy], and uses the [[standard]] [[color]] codes of the [http://en.wikipedia.org/wiki/United_States_Geological_Survey United States Geological Survey].

The '''geologic time scale''' provides a [[system]] of chronologic [[measure]]ment relating [http://en.wikipedia.org/wiki/Stratigraphy stratigraphy] to [[time]] that is used by geologists, paleontologists and other [[Earth Science|earth scientists]] to describe the [[timing]] and [[relationships]] between [[events]] that have occurred during the [https://nordan.daynal.org/wiki/index.php?title=The_Urantia_Text_-_Contents#Part_III._The_History_of_Urantia history of the Earth][http://en.wikipedia.org/wiki/History_of_the_Earth]. The table of geologic time spans presented here agrees with the dates and [[Names|nomenclature]] proposed by the [http://en.wikipedia.org/wiki/International_Commission_on_Stratigraphy International Commission on Stratigraphy], and uses the [[standard]] [[color]] codes of the [http://en.wikipedia.org/wiki/United_States_Geological_Survey United States Geological Survey].

[[Evidence]] from [http://en.wikipedia.org/wiki/Radiometric_dating radiometric dating] indicates that the [[Earth]] is about 4.570 billion years old. The geological or deep time of Earth's past has been organized into various units according to [[events]] which took place in each period. Different spans of time on the time scale are usually delimited by major geological or paleontological events, such as [[Catastrophism|mass extinctions]]. For example, the boundary between the Cretaceous period and the Paleogene period is defined by the [http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Tertiary_extinction_event Cretaceous–Tertiary extinction event], which marked the demise of the [http://en.wikipedia.org/wiki/Dinosaur dinosaurs] and of many marine species. Older periods which predate the reliable fossil record are defined by absolute age.

[[Evidence]] from [http://en.wikipedia.org/wiki/Radiometric_dating radiometric dating] indicates that the [[Earth]] is about 4.570 billion years old. The geological or deep time of Earth's past has been organized into various units according to [[events]] which took place in each period. Different spans of time on the time scale are usually delimited by major geological or paleontological events, such as [[Catastrophism|mass extinctions]]. For example, the boundary between the Cretaceous period and the Paleogene period is defined by the [http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Tertiary_extinction_event Cretaceous–Tertiary extinction event], which marked the demise of the [http://en.wikipedia.org/wiki/Dinosaur dinosaurs] and of many marine species. Older periods which predate the reliable fossil record are defined by absolute age.