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How can lead-210 dating estimate the age of glacial ice and recent sediments?

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dating Layered strata in an outcropping of the Morrison Formation on the west side of Dinosaur Ridge, near Denver, Colorado.

Lead-210 dating is a method of geochronology used to determine the age of relatively recent materials, such as glacial ice and lacustrine or coastal marine sediments.123

The process relies on the uranium-decay scheme. Radon-222 gas, a member of this decay chain, escapes from the ground into the atmosphere, where it rapidly decays into lead-210. This lead-210 then falls to the Earth's surface and becomes incorporated into accumulating layers of glacial ice and sedimentary materials.2

To estimate the age of a sample at a specific depth, researchers measure the residual amount of lead-210 remaining in the material. By assuming that the rate of deposition has remained constant over time, the age can be calculated based on the isotope's decay. Because lead-210 has a relatively short half-life of approximately 22.26 years, it is particularly effective for dating events in the recent geologic past.23