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.
Geophysical Research Letters
American Geophysical Union (AGU)
Digital Object Identifier (DOI)
Yang, Q., Mayewski, P. A., Zielinski, G. A., Twickler, M., & Taylor, K. C. (1996). Depletion of atmospheric nitrate and chloride as a consequence of the Toba Volcanic Eruption. Geophysical Research Letters, 23(18), 2513-2516. doi:10.1029/96GL02201
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