A 2,000-year-old historical figure guides new insights on dating volcanic eruptions
Researchers supported by the U.S. National Science Foundation confirmed the date of an almost 2,000-year-old volcanic eruption, establishing a new benchmark for dating past eruptions and improving forecasts for future events.
After Mt. Vesuvius erupted in August 79 C.E., Pliny the Younger recorded his first-hand experience watching pumice, ash, small particles of molten lava, and hot pyroclastic currents bury Pompeii. His detailed reporting of the month and day helped researchers recalibrate an important dating method.
The match between the date Pliny the Younger recorded and the date revealed through argon-argon dating confirmed the latter as one of the most versatile dating methods currently available.
Argon-argon dating relies on the natural decay of potassium-40 in volcanic rock to argon-40, which is generally absent in minerals prior to eruption.
The team recalibrated the argon-argon dating method and used it on eight samples of a potassium-containing volcanic mineral from Vesuvius, validating the recorded eruption date within two months. The findings allowed the team to recalculate the half-life of the decay of potassium-40 to argon-40, making the measurement twice as precise as the previous value determined through nuclear physics.
The improvements in argon-argon dating accuracy and precision also help validate other dating methods, such as radiocarbon dating, the leading method to date materials like wood less than 55,000 years old.