Search results
Results from the WOW.Com Content Network
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [3] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
Download as PDF; Printable version; ... rocks older than 3.6 Billion years [1] [2 ... chart; Geotime chart displaying geologic time periods compared to the fossil ...
Units in geochronology and stratigraphy [1] Segments of rock in chronostratigraphy Time spans in geochronology Notes to geochronological units Eonothem: Eon: 4 total, half a billion years or more Erathem: Era: 10 defined, several hundred million years System: Period: 22 defined, tens to ~one hundred million years Series: Epoch
In the stratigraphy sub-discipline of geology, a Global Standard Stratigraphic Age, abbreviated GSSA, is a chronological reference point and criterion in the geologic record used to define the boundaries (an internationally sanctioned benchmark point) between different geological periods, epochs or ages on the overall geologic time scale in a chronostratigraphically useful rock layer.
Units in geochronology and stratigraphy [1] Segments of rock in chronostratigraphy Time spans in geochronology Notes to geochronological units Eonothem: Eon: 4 total, half a billion years or more Erathem: Era: 10 defined, several hundred million years System: Period: 22 defined, tens to ~one hundred million years Series: Epoch
"The ICS International Chronostratigraphic Chart" (PDF). 2017/02. pp. 199–204. U.S. Geological Survey Geologic Names Committee. "Divisions of Geologic Time—Major Chronostratigraphic and Geochronologic Units" (PDF). USGS. Fact Sheet 2007-3015
The Precambrian includes approximately 90% of geologic time. It extends from 4.6 billion years ago to the beginning of the Cambrian Period (about 539 Ma). It includes the first three of the four eons of Earth's prehistory (the Hadean, Archean, and Proterozoic) and precedes the Phanerozoic eon. [6]
The geological time scale (GTS), as defined by international convention, [3] depicts the large spans of time from the beginning of the Earth to the present, and its divisions chronicle some definitive events of Earth history. Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar ...