Individual glass shard trace element analyses confirm that all known Toba tephra reported from India is from the c. 75-ka Youngest Toba eruption

Nicholas J. G. Pearce*, John A. Westgate, Emma Gatti, Jinnappa N. Pattan, Gopal Parthiban, Hema Achyuthan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (SciVal)

Abstract

Uncertainty over the identity and age of Toba tephras across peninsular India persists, with radiometric age dates contradicting earlier compositional data, which have been used to identify this important stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.

Original languageEnglish
Pages (from-to)729-734
Number of pages6
JournalJournal of Quaternary Science
Volume29
Issue number8
DOIs
Publication statusPublished - Nov 2014

Keywords

  • glass shards
  • India
  • Oldest Toba Tuff
  • tephra
  • Toba
  • trace elements
  • Youngest Toba Tuff
  • ULTRA-DISTAL TEPHRA
  • PRECISION AR-40/AR-39 AGE
  • MULTIPLE INTERPRETIVE ERRORS
  • MIDDLE SON VALLEY
  • PENINSULAR INDIA
  • NORTHERN SUMATRA
  • TUFF
  • INDONESIA
  • SEDIMENTS
  • SUPERERUPTION

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