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Geophysical Research Letters

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Abstract/ Summary

Continuous measurements of SO42− and electrical conductivity (ECM) along the GISP2 ice core record the Toba mega‐eruption at a depth 2590.95 to 2091.25 m (71,000±5000 years ago). Major chemical species were analyzed at a resolution of 1 cm per sample for this section. An ∼6‐year long period with extremely high volcanic SO42− coincident with a 94% depletion of nitrate and 63% depletion of chloride is observed at the depth of the Toba horizon. Such a reduction of chloride in a volcanic layer preserved in an ice core has not been observed in any previous studies. The nearly complete depletion of nitrate (to 5 ppb) encountered at the Toba level is the lowest value in the entire ∼250,000 years of the GISP2 ice core record. We propose possible mechanisms to explain the depletion of nitrate and chloride resulting from this mega‐eruption.

Citation/Publisher Attribution

Yang, Q., P. A. Mayewski, G. A. Zielinski, M. Twickler, and K. C. Taylor (1996), Depletion of atmospheric nitrate and chloride as a consequence of the Toba Volcanic Eruption, Geophys. Res. Lett., 23(18), 2513–2516, doi:10.1029/96GL02201.

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