U–Pb dating

U–Pb dating estimates the ages of rocks and minerals from radioactive decay of uranium isotopes into lead isotopes. Its two independent decay chains allow dates to be tested for consistency.

Uranium-238–lead-206 dating: A geochronological method that dates materials using the decay of uranium-238 to lead-206. This decay chain supplies one of U–Pb dating’s two independent clocks.
Radioactive decay: The spontaneous transformation of unstable atomic nuclei into other nuclei, often with emission of particles or radiation. U–Pb clocks rely on decay rates that remain stable over geological time.
Geochronology: The science of determining the ages and timing of events in Earth’s history. U–Pb dating is one of geochronology’s principal methods for deep time.
Potassium–argon dating: A radiometric method that dates materials using the decay of potassium-40 to argon-40. Unlike U–Pb dating, it commonly uses potassium-bearing minerals and volcanic rocks.
Radioactivity: The emission of particles or electromagnetic radiation from unstable atomic nuclei. The discovery of radioactivity made radioactive clocks for geological time possible.
Uranium-235–lead-207 dating: A geochronological method that dates materials using the decay of uranium-235 to lead-207. Its independent age can be compared with the uranium-238 clock.
Half-life: The time required for half the radioactive atoms in a sample to decay. The long uranium half-lives make the method useful for ancient rocks.
Geologic time scale: A chronological system that divides Earth’s history into named eons, eras, periods, and smaller intervals. U–Pb ages help calibrate boundaries and events in the time scale.
Rubidium–strontium dating: A radiometric method that uses the decay of rubidium-87 to strontium-87. Its parent and daughter elements have different mineral behavior from uranium and lead.
Ernest Rutherford: A physicist who established the nuclear model of the atom and helped develop early radioactive dating. Rutherford showed how radioactive transformations could measure geological ages.

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