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After the Cretaceous, a new era of geologic time began; the Cenozoic era, which means the era of "recent life". Traditionally, the first period of the Cenozoic was called the Tertiary , [ 131 ] however recent recommendations of the International Commission on Stratigraphy discourage its use, with the correspondent time span divided between the ...
Elsewhere in North America, as in Illinois, the Yarmouth Soil also has developed over a variable number of multiple glacial - interglacial cycles. [4] [8] Thus, the presumption that the Yarmouth Soil, by which the Yarmouthian (Yarmouth) Interglacial was later defined, represents a single interglacial stage or period has been completely discredited.
Geologic Time – Period prior to humans. 4.6 billion to 3 million years ago. (See "prehistoric periods" for more detail into this.) (See "prehistoric periods" for more detail into this.) Primatomorphid Era – Period prior to the existence of Primatomorpha
Sevier orogeny – Mountain-building episode in North America – Rocky Mountains, western North America, (140–50 Ma) Laramide orogeny – Period of mountain building in North America – Rocky Mountains, western North America, (40–70 Ma) Pasadena orogeny – Transverse Ranges, western North America, Pleistocene Period to present day
The term geon (for geological eon) refers to large, geologic units of time. Geologists traditionally subdivide Earth history into a hierarchy of named intervals: eons, eras, periods, etc. (e.g., the Jurassic Period of the Mesozoic Era). Historians subdivide the history of human activity into intervals that are comparatively much shorter.
It precedes the Sangamonian Stage (corresponding to the global Last Interglacial) and follows the Pre-Illinoian Stage in North America. The Illinoian Stage is defined as the period of geologic time during which the glacial tills and outwash, which comprise the bulk of the Glasford Formation, accumulated to create the Illinoian Glacial Lobe. [1]
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 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).