Radiometric dating

Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay.^[1] The use of radiometric dating was first published in 1907 by Bertram Boltwood^[2] and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of Earth itself, and can also be used to date a wide range of natural and man-made materials.

Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geologic time scale.^[3] Among the best-known techniques are radiocarbon dating, potassium–argon dating and uranium–lead dating. By allowing the establishment of geological timescales, it provides a significant source of information about the ages of fossils and the deduced rates of evolutionary change. Radiometric dating is also used to date archaeological materials, including ancient artifacts.

Different methods of radiometric dating vary in the timescale over which they are accurate and the materials to which they can be applied.

$t$ is age of the sample,

$D *$ is number of atoms of the radiogenic daughter isotope in the sample,

$D 0$ is number of atoms of the daughter isotope in the original or initial composition,

$N (t)$ is number of atoms of the parent isotope in the sample at time t (the present), given by $N (t) = N 0 e - λt$ , and

$λ$ is the of the parent isotope, equal to the inverse of the radioactive half-life of the parent isotope^[17] times the natural logarithm of 2.

decay constant

(Ar–Ar)

Argon–argon

(I–Xe)

Iodine–xenon

(La–Ba)

Lanthanum–barium

(Pb–Pb)

Lead–lead

(Lu–Hf)

Lutetium–hafnium

(Hf-W)

Hafnium–tungsten dating

(K–Ca)

Potassium–calcium

(Re–Os)

Rhenium–osmium

(U–U)

Uranium–uranium

(Kr–Kr)

Krypton–krypton

(¹⁰Be–⁹Be)^[35]

Beryllium

Hadean zircon

Isotope geochemistry

Paleopedological record

Radioactivity

Radiohalo

(SHRIMP)

Sensitive high-resolution ion microprobe

Gunten, Hans R. von (1995). (PDF). Radiochimica Acta. 70–71 (s1): 305–413. doi:10.1524/ract.1995.7071.special-issue.305. S2CID 100441969.

"Radioactivity: A Tool to Explore the Past"

Magill, Joseph; Galy, Jean (2005). "Archaeology and Dating". Radioactivity Radionuclides Radiation. Springer Berlin Heidelberg. pp. 105–115. :2005rrr..book.....M. doi:10.1007/3-540-26881-2_6. ISBN 978-3-540-26881-9.

Bibcode

Allègre, Claude J (4 December 2008). Isotope Geology. Cambridge University Press. 978-0521862288.

ISBN

McSween, Harry Y; Richardson, Steven Mcafee; Uhle, Maria E; Uhle, Professor Maria (2003). Geochemistry: Pathways and Processes (2 ed.). Columbia University Press. 978-0-231-12440-9.

ISBN

Harry y. Mcsween, Jr; Huss, Gary R (29 April 2010). Cosmochemistry. Cambridge University Press. 978-0-521-87862-3.