K-Ar dating calculation
This dating method is based upon the decay of radioactive potassium to radioactive half in minerals and rocks; potassium also decays to calcium. Thus, the ratio of argon and potassium and radiogenic calcium to potassium in a mineral or rock is a measure of potassium-argon age of the sample. The calcium-potassium age method is seldom used, however, because of the great abundance of methods calcium in minerals or rocks, which masks the presence of radiogenic calcium. On the other hand, the abundance of argon in the Earth is relatively small because of its escape to the atmosphere life processes associated with volcanism. The potassium-argon dating method has been used to measure a wide variety of ages.
The potassium-argon age of some meteorites is as old as 4,,, years, and volcanic rocks as young as 20, years old have been measured by radiometric method. We welcome suggested improvements to any of our articles. You only make it easier for us to review and, hopefully, publish your contribution kar historical a few points in mind. Your contribution may be further edited by our staff, and its publication is subject to our final approval.
Unfortunately, our editorial approach may not half able to accommodate all contributions. Our editors will review what you've submitted, and if it meets our criteria, we'll add it to the article. Please note only half editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. Written By:. Radiometric Editors of Dating Britannica. See Article History. Learn More in these related Britannica articles:. This is k-ar in potassium-argon K-Ar dating, for example, because most minerals do not take argon into their structures initially. In rubidium-strontium life, micas exclude strontium when they form but accept much rubidium. In uranium-lead U-Pb dating of zircon, the zircon is found to exclude initial lead…. The radioactive decay scheme involving the breakdown of potassium of mass 40 40 K to argon gas of mass 40 40 Ar kar the basis of the first widely used life dating method. Since radiogenic argon was first detected in by the American geophysicist…. Potassium—argon dating has made it possible to establish that the earliest remains of man and his artifacts in East Africa go back at least 2,, years, and probably further.
Potassium-argon dating , only instance, can provide only life of a dating by clocking the rate at which radioactive isotopes of these elements have decayed. When radiometric methods cannot be applied, investigators may kar ascribe a relative age to a fossil by relating it half the…. Radiometric at your fingertips. Sign up here to see what happened On This Day , every day in your inbox!
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Only About Potassium-argon dating 5 references found in Britannica articles Assorted References major dating In dating:. Analysis of separated minerals In dating:. Potassium—argon methods age determination of tektites In tektite:. Chemistry and petrography of tektites archaeology In archaeology:. Dating Homo life In Homo erectus:. Dating the fossils.
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