disequilibrium dating
Quick Summary
Uranium-series disequilibrium dating is a method used in geology to determine the age of geologically young materials. This technique relies on the decay chains of radioactive elements like uranium and thorium, which have short half-lives suitable for dating recent samples.12
In natural, closed systems, intermediate daughter elements within these decay chains exist in equilibrium. However, when a uranium-bearing mineral dissolves, this equilibrium can be disrupted. For instance, thorium isotopes, normally in equilibrium with uranium-234, can become depleted. Over time, uranium-234 decays into thorium-230, leading to a buildup of thorium-230 in materials like old corals. This accumulation provides a precise measure of time.12
Methods like lead-210 dating and thorium-230 dating utilize these disequilibrium principles. Lead-210 dating uses radon gas from the uranium decay chain, while thorium-230 dating leverages the insoluble nature of thorium to determine sedimentation rates. The development of sensitive mass spectrometers has revolutionized these techniques, allowing for the measurement of total atoms rather than just decaying ones.12
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
