Astronomically calibrated 40 Ar/ 39 Ar age for the Toba supereruption and global synchronization of late Quaternary records

A high-precision astronomically calibrated (40)Ar/(39)Ar age of 73.88 ± 0.32 thousand years for the Toba supereruption in Sumatra, an order-of-magnitude more accurate than previous estimates, has been determined. This finding places the eruption at the midpoint of a cold interval between Dansgaard-Oeschger events 20 and 19, coinciding with a sulfate concentration peak in Greenland ice cores and a subsequent ∼10 °C temperature drop over ∼150 years. The age also provides a critical calibration point for synchronizing global late Quaternary records, including ice, marine, and terrestrial archives containing Toba sulfates and ash, beyond the range of (14)C dating. Additionally, if stone artifacts in the Lenggong Valley, Malaysia, were made by Homo sapiens, this suggests modern humans had reached Southeast Asia by ∼74 thousand years ago.

Storey, M., Roberts, R. G., & Saidin, M. (2012). Astronomically calibrated ⁴⁰ Ar/ ³⁹ Ar age for the Toba supereruption and global synchronization of late Quaternary records. Proceedings of the National Academy of Sciences, 109(46), 18684–18688. https://doi.org/10.1073/pnas.1208178109