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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.
Rhenium–osmium dating is a form of radiometric dating based on the beta decay of the isotope 187 Re to 187 Os.This normally occurs with a half-life of 41.6 × 10 9 y, [1] but studies using fully ionised 187 Re atoms have found that this can decrease to only 33 y. [2]
In 2017, the successful dating of illite formed by weathering was reported. [10] This finding indirectly led to the dating of the strandflat of Western Norway from where the illite was sampled. [10] Clay minerals are less than 2 μm thick and cannot easily be irradiated for Ar–Ar analysis because Ar recoils from the crystal lattice.
Radiometric dating continues to be the predominant way scientists date geologic time scales. Techniques for radioactive dating have been tested and fine-tuned on an ongoing basis since the 1960s. Forty or so different dating techniques have been utilized to date, working on a wide variety of materials.
The radioactive system behind hafnium–tungsten dating is a two-stage decay as follows: 182 72 Hf → 182 73 Ta e − ν e 182 73 Ta → 182 74 W e − ν e. The first decay has a half-life of 8.9 million years, while the second has a half-life of only 114 days, [7] such that the intermediate nuclide tantalum-182 (182 Ta) can effectively be ignored.
The rubidium–strontium dating method (Rb–Sr) is a radiometric dating technique, used by scientists to determine the age of rocks and minerals from their content of specific isotopes of rubidium (87 Rb) and strontium (87 Sr, 86 Sr). One of the two naturally occurring isotopes of rubidium, 87 Rb, decays to 87 Sr with a half-life of 49.23 ...
In the case of dating megalithic tombs, indirect evidence for the age of the tomb must always be obtained, because stone (or the time of moving a stone) cannot be dated. When a number of objects are recovered from one deposit, the terminus post quem is based on the dating from the 'youngest' find. Even though other items in the same stratum ...
Hadean zircon is the oldest-surviving crustal material from the Earth's earliest geological time period, the Hadean eon, about 4 billion years ago. Zircon is a mineral that is commonly used for radiometric dating because it is highly resistant to chemical changes and appears in the form of small crystals or grains in most igneous and metamorphic host rocks.