About radiometric dating
Much information about tektite history is obtained by radioisotopic dating; the ages cited above for the tektite strewn-fields were found by potassium-argon dating.
One new and fundamental result has come from radiometric age dating of the samples.
This motion of the surrounding gas molecules causes the paddles to spin.
Precision radiometers, which use a complete vacuum rather than a gas, exploit the difference in radiation pressure on either side of the paddles to cause them to spin.
Radiometric dating of granitic intrusions associated with the Caledonian orogeny yields ages between about 430 million and 380 million years.
The igneous activity that produced such intrusions...
In 1905, shortly after the discovery of radioactivity, the American chemist Bertram Boltwood suggested that lead is one of the disintegration products of uranium, in which case the older a uranium-bearing mineral the greater should be its proportional part of lead.
Atomic nuclei of a radioactive element decay spontaneously, producing other elements and isotopes until a stable species is formed.
The life span of a single atom may have any value, but a statistical quantity, the half-life of a macroscopic sample, can be measured; this is the time in which one-half of the sample disintegrates.
Radioactive elements in the Earth, the Moon, and in meteorites can provide useful information about the ages of these objects and about the dates of formation of the heavy elements themselves.
The elements uranium and thorium gradually decay into lead, different isotopes of lead arising from the various isotopes of uranium and thorium; some isotopes of lead are, however, not produced by any...