Overview
- Researchers at the Berkeley Geochronology Center used Pliny the Younger’s historical account as a benchmark to recalibrate argon-argon dating on pumice from Mount Vesuvius.
- The recalibrated measurements yield an eruption age centered on 87 CE with a formal uncertainty of ±13 years, showing the method can resolve very recent eruptions to about a decade.
- The team analyzed eight potassium-rich sanidine pumice samples, including material from Oplontis collected decades ago, and used improved instrumentation and irradiation to reduce measurement error.
- Their work produced a more precise value for the potassium-40 to argon-40 decay parameter (reported as 12.044 ± 0.088 billion years) and thus tightened the argon-argon clock.
- Co-author Caroline Hasler defended using Pliny’s August 24, 79 CE date by reexamining a contested coin, and the authors say the new calibration can help align argon-argon, uranium-lead and radiocarbon dating with direct benefits for archaeology and volcanic-risk studies.