N. J. Shackleton A. A. Abdel-Monem J. D. Obradovich G. Izett D. Ninkovich 1978 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 [~amp]sim; 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. ?? 1978 Nature Publishing Group. application/pdf 10.1038/276574a0 en K-Ar age of the late Pleistocene eruption of Toba, north Sumatra article