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The geological time scale relates stratigraphy to time. The deep time of Earth's past is divided into units according to events that took place in each period. For example, the boundary between the Cretaceous period and the Paleogene period is defined by the Cretaceous–Paleogene extinction event. The largest unit is the supereon, composed of ...
Time scale may refer to: Time standard, a specification of either the rate at which time passes, points in time, or both; A duration or quantity of time: Orders of magnitude (time) as a power of 10 in seconds; A specific unit of time; Geological time scale, a scale that divides up the history of Earth into scientifically meaningful periods
The Rancholabrean North American Land Mammal Age on the geologic timescale is a North American faunal stage in the North American Land Mammal Ages chronology (NALMA), [1] named after the famed Rancho La Brea fossil site (more commonly known as the La Brea tar pits) in Los Angeles, California. [2]
Ephemeris time (ET), adopted as standard in 1952, was originally designed as an approach to a uniform time scale, to be freed from the effects of irregularity in the rotation of the Earth, "for the convenience of astronomers and other scientists", for example for use in ephemerides of the Sun (as observed from the Earth), the Moon, and the planets.
While many timelines use a linear timescale—especially where very large or small timespans are relevant -- logarithmic timelines entail a logarithmic scale of time; some "hurry up and wait" chronologies are depicted with zoom lens metaphors. More usually, "timeline" refers merely to a data set which could be displayed as described above.
A time scale (or measure chain) is a closed subset of the real line. The common notation for a general time scale is T {\displaystyle \mathbb {T} } . The two most commonly encountered examples of time scales are the real numbers R {\displaystyle \mathbb {R} } and the discrete time scale h Z {\displaystyle h\mathbb {Z} } .
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The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently defined as the time between c. 129,000 and c ...