A new study has refined argon-argon dating thanks to the historical accounts surrounding the eruption of Mt. Vesuvius nearly 2,000 years ago, which destroyed Pompeii. This research, published on September 25 in the journal Science Advances, involves scientists from the Berkeley Geochronology Center, UC Berkeley, and the University of Padua in Italy.
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The eruption, which occurred on August 24, 79 C.E., was documented in detail by Pliny the Younger, whose observations provided critical timelines for scientists to enhance volcanic dating methods. By recalibrating argon-argon dating with this understood date, researchers have achieved significantly improved precision.
Paul Renne, study leader and professor of earth and planetary science, noted that achieving high precision in dating is crucial for examining the eruptive history of volcanoes. The upgraded method now allows geologists, paleontologists, and archaeologists to more accurately associate dates with geological events. This improvement will also aid in verifying other dating techniques, such as carbon-14 and uranium-lead dating.
The recalibration process involved analyzing eight samples of a potassium-rich volcanic mineral from Vesuvius called sanidine, resulting in a dating estimate of 1,938 ±13 years prior to the analysis conducted in 2025. This aligns closely with the actual age of the volcanic minerals, estimated at 1,946 years, yielding precision and accuracy rates of 0.7% and 0.4%, respectively.
Renne emphasized the method's utility in establishing causal relationships in the geological record. The team, involving student Caroline Hasler, confirmed the eruption date attributed to Pliny the Younger with greater accuracy, which in turn allowed for a refined measurement of the half-life used in argon-argon dating, now determined at 12.044 billion years.
Additionally, the researchers benefited from improved samples, advanced mass spectrometry techniques, and updated irradiation methods, allowing them to obtain precise measurements from previously unexamined pumice samples from Oplontis. The study's findings not only enhance dating methods for recent geological events but also establish benchmarks for future applications in related fields.
The work was supported by the National Science Foundation and other organizations, showcasing a commitment to understanding geological history through improved precision in dating methods.