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Geochronology

jee-oh-kruh-NOL-uh-jee
Branch of Geology

The discipline that dates deep time itself: the radioactive decay, layered rock and fossil sequences that let geologists put a number of years on an era nobody was alive to clock. It carries this atlas's deep-time history spine. Its workhorse method is uranium-lead dating, applied to the mineral zircon in igneous rock and, alongside argon-argon dating, one of the two techniques geochronologists rely on most for reading ages older than about a million years. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/

Facts
Central Question
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. 1
Scope
Geochronology develops and applies the methods, principally radiometric dating, used to determine the age of rocks, fossils and geological events. 1
Significance
Geochronology anchors the geologic time scale in absolute years and dates events from the age of the Earth to the timing of mass extinctions. 1
Geochronology
Filter Results7 entries
FAQs

How do geologists know how old a rock or fossil actually is?

Mainly through radiometric dating, which measures the ratio of a radioactive element to its stable decay product and converts that ratio into an age using the element's known, fixed decay rate.

Geochronologists mainly use radiometric dating, which measures the ratio of a radioactive element to the stable element it decays into inside a mineral or rock. Because that decay happens at a fixed, known rate, the ratio can be converted into an age. Different radioactive systems suit different age ranges and materials, which is why geochronology uses several distinct dating methods rather than one universal clock.
Connections

Associated With

The record of geomagnetic reversals provides a time scale used as a geochronologic tool.

Source Paleomagnetism (Wikipedia)

Has Scientist

Includes

Anthropocene, Concepts
Source Anthropocene (Wikipedia)
Apatite, Materials

Apatite is a standard mineral used in fission-track and (U-Th)/He geochronology dating methods, beyond the automatic in-discipline->Mineralogy edge.

Source Apatite (Wikipedia)
Archean, Eras
Source Geologic Time Scale (Wikipedia)
Calymmian, Eras
Cambrian, Eras
Source Geologic Time Scale (Wikipedia)
Cenozoic, Eras
Source Geologic Time Scale (Wikipedia)
Source Chicxulub Crater (Wikipedia)
Cretaceous, Eras
Source Geologic Time Scale (Wikipedia)
Cryogenian, Eras
Ectasian, Eras
Eoarchean, Eras
Eocene, Eras
Source Geologic Time Scale (Wikipedia)
Source Great Oxidation Event (Wikipedia)
Hadean, Eras
Source Geologic Time Scale (Wikipedia)
Holocene, Eras
Source Geologic Time Scale (Wikipedia)
Jurassic, Eras
Source Geologic Time Scale (Wikipedia)
Mesoarchean, Eras
Mesoproterozoic, Eras
Mesozoic, Eras
Source Geologic Time Scale (Wikipedia)
Miocene, Eras
Neoarchean, Eras
Neoproterozoic, Eras
Oligocene, Eras
Orosirian, Eras
Paleoarchean, Eras
Paleocene, Eras
Paleoproterozoic, Eras
Paleozoic, Eras
Source Geologic Time Scale (Wikipedia)
Phanerozoic, Eras
Source Geologic Time Scale (Wikipedia)
Pleistocene, Eras
Source Geologic Time Scale (Wikipedia)
Pliocene, Eras
Proterozoic, Eras
Source Geologic Time Scale (Wikipedia)
Quaternary, Eras
Source Radiometric Dating (Wikipedia)
Rhyacian, Eras
Siderian, Eras
Statherian, Eras
Stenian, Eras
Tonian, Eras
Sources
1. Geochronology (Wikipedia)
Wikimedia Foundation
  • Lead paragraph, opening sentence
    Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves.
  • Dating methods, Radiometric dating section
    Often applied to the trace mineral zircon in igneous rocks, this method is one of the two most commonly used (along with argon-argon dating) for geologic dating.
View the Source
Apatite (Wikipedia)
Wikimedia FoundationIncludes: Apatite, Applications section
Quote, Includes: Apatite, Applications section
Fission tracks in apatite are commonly used to determine the thermal histories of orogenic belts and of sediments in sedimentary basins.
View the Source
Anthropocene (Wikipedia)
Wikimedia FoundationIncludes: AnthropoceneView the Source
Great Oxidation Event (Wikipedia)
Includes: Great Oxidation Event, Lead paragraph
Quote, Includes: Great Oxidation Event, Lead paragraph
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis, or Oxygen Holocaust, was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen.
View the Source
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