The calcium-potassium age method is seldom used, however, because of the great abundance of nonradiogenic calcium in minerals or rocks, which masks the presence of radiogenic calcium.
plants that take in carbon through C3 photosynthesis, which changes carbon dioxide into a compound having three carbon atoms.
Tending to be from more temperate regions these plants include wheat, sugar beets, peas, and a range of hardwood treesplants that take in carbon C4 photosynthesis, which changes carbon dioxide into a compound with four carbon atoms.
Thus, the ratio of naturally produced, spontaneous fission tracks to neutron-induced fission tracks is a measure of the age of the sample.
A wide variety of minerals have been fission-track dated, as have natural and artificial glasses.
The process of track production is essentially the same by which swift heavy ions produce ion tracks.
Chemical etching of polished internal surfaces of these minerals reveals spontaneous fission tracks, and the track density can be determined.
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. 1979, 1986 © Harper Collins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cite This Source potassium-argon dating A method of radiometric dating, involving analysis of the ratio of potassium 40 (a radioactive isotope of potassium) to argon (the product of radioactive decay of potassium 40) in a given sample.
Fission-track dating is a relatively simple method of radiometric dating that has made a significant impact on understanding the thermal history of continental crust, the timing of volcanic events, and the source and age of different archeological artifacts.
method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays to calcium-40.