Australia: The Land Where Time Began

A biography of the Australian continent 

All Toba Tephra Occurrences across Peninsular India Belong to the 75,000 Yr B.P. Eruption

According to the authors¹ the number of eruptions of Mt Toba in Indonesia that are recorded in the occurrences of tephra across peninsula India are being debated. There are some claiming that all the tephra layers found are from a single event at 75,000 BP, though others claim that tephra from earlier eruptions of Toba are also present as suggested by dating and archaeological evidence In this paper the authors¹ report their attempt to resolve this issue by geochemical analyses of a comprehensive suite of samples, that allows the comparisons of the samples from India to those taken from the Mt Toba caldera in the north of Sumatra in Indonesia, Malaysia, and importantly, the sedimentary cores obtained at the ODP Site 758 in the Indian Ocean, which contains several of tephra beds from earlier Toba eruptions. Also, the fission-track method was used to date 2 tephra samples from western India. It is demonstrated unequivocally by the results that all the tephra deposits from Toba that are known of in peninsula India are from the Toba eruption of 75,000 BP. Therefore this tephra bed can be used as an effective tool to correlate the dating of sedimentary sequences from the Late Quaternary across India and not in support of the Middle Pleistocene age for associated Acheulian artefacts.

Sources & Further reading

1. Westgate, John A., Philip A. R. Shane, Nicholas J. G. Pearce, William T. Perkins, Ravi Korisettar, Craig A. Chesner, Martin A. J. Williams, and Subhrangsu K. Acharyya. "All Toba Tephra Occurrences across Peninsular India Belong to the 75,000 Yr B.P. Eruption." Quaternary Research 50, no. 1 (7// 1998): 107-12.