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Uranium–lead dating, abbreviated U–Pb dating, is one of the oldest [1] and most refined of the radiometric dating schemes. It can be used to date rocks that formed and crystallised from about 1 million years to over 4.5 billion years ago with routine precisions in the 0.1–1 percent range. [2] [3] The method is usually applied to zircon.
Uranium-lead dating is usually performed on the mineral zircon (ZrSiO 4), though other materials can be used. Zircon incorporates uranium atoms into its crystalline structure as substitutes for zirconium, but strongly rejects lead. It has a high blocking temperature, is resistant to mechanical weathering and is chemically inert.
One of its great advantages is that any sample provides two clocks, one based on uranium-235's decay to lead-207 with a half-life of about 700 million years, and one based on uranium-238's decay to lead-206 with a half-life of about 4.5 billion years, providing a built-in crosscheck that allows accurate determination of the age of the sample ...
Monazite geochronology is another example of U–Pb dating, employed for dating metamorphism in particular. Uranium–lead dating is applied to samples older than about 1 million years. Uranium–thorium dating. This technique is used to date speleothems, corals, carbonates, and fossil bones. Its range is from a few years to about 700,000 years.
Lead–lead dating is a method for dating geological samples, normally based on 'whole-rock' samples of material such as granite.For most dating requirements it has been superseded by uranium–lead dating (U–Pb dating), but in certain specialized situations (such as dating meteorites and the age of the Earth) it is more important than U–Pb dating.
In rocks that contain uranium and thorium, the excess amounts of the three heavier lead isotopes allows the rocks to be "dated", thus providing a time estimate for when the rock solidified and the mineral held the ratio of isotopes fixed and in place. Another notable radiogenic nuclide is argon-40, formed from radioactive potassium. Almost all ...
In 2007, using uranium–lead dating on zircons, the Nuvvuagittuq was dated to be a minimum of 3.75 billion years old [2] (3,750 Ma). This measurement was made using uranium–lead dating on zircons found within granitic intrusions that cut portions of the belt, and therefore, are younger than the features it cuts. This measurement is widely ...
However, uranium–lead dating on zircon [4] and Argon-argon dating on sanidine and hornblende are the two single methods that achieve today the best results. [5] Other methods of radiometric dating are also available, that are based on slightly or largely different principles, but always rely on the phenomenon of radioactive decay. These ...