K–Ar age of the late Pleistocene eruption of Toba, north Sumatra

The late Pleistocene eruption of Toba is the largest magnitude explosive eruption documented from the Quaternary. K–Ar dating of the uppermost unit of the Toba Tuff gives an age of ∼ 75,000 yr. A chemically and petrographically equivalent ash layer in deep-sea cores helps calibrate the Stage 4–5 boundary of the standard oxygen isotope stratigraphy. A similar ash in Malaya that overlies finds of Tampan Palaeolithic tools indicates that they are older than 75,000 yr.