In:
Climate of the Past, Copernicus GmbH, Vol. 17, No. 5 ( 2021-10-18), p. 2119-2137
Abstract:
Abstract. The ∼74 ka Toba eruption was one of the
largest volcanic events of the Quaternary. There is much interest in
determining the impact of such a large event, particularly on the climate
and hominid populations at the time. Although the Toba eruption has been
identified in both land and marine archives as the Youngest Toba Tuff, its
precise place in the ice core record is ambiguous. Several volcanic sulfate
signals have been identified in both Antarctic and Greenland ice cores and
span the Toba eruption 40Ar/39Ar age uncertainty. Here, we measure
sulfur isotope compositions in Antarctic ice samples from the Dome C
(EDC) and Dronning Maud Land (EDML)
ice cores at high temporal resolution across 11 of these potential Toba
sulfate peaks to identify candidates with sulfur mass-independent
fractionation (S-MIF), indicative of an eruption whose plume reached
altitudes at or above the stratospheric ozone layer. Using this method, we
identify several candidate sulfate peaks that contain stratospheric sulfur.
We further narrow down potential candidates based on the isotope signatures
by identifying sulfate peaks that are due to a volcanic event at tropical
latitudes. In one of these sulfate peaks at 73.67 ka, we find the largest
ever reported magnitude of S-MIF in volcanic sulfate in polar ice, with a
Δ33S value of −4.75 ‰. As there is a
positive correlation between the magnitude of the S-MIF signal recorded in
ice cores and eruptive plume height, this could be a likely candidate for
the Toba super-eruption, with a plume top height in excess of 45 km. These
results support the 73.7±0.3 ka (1σ) 40Ar/39Ar
age estimate for the eruption, with ice core ages of our candidates with the
largest magnitude S-MIF at 73.67 and 73.74 ka. Finally, since these
candidate eruptions occurred on the transition into Greenland Stadial 20,
the relative timing suggests that Toba was not the trigger for the large
Northern Hemisphere cooling at this time although we cannot rule out an
amplifying effect.
Type of Medium:
Online Resource
ISSN:
1814-9332
DOI:
10.5194/cp-17-2119-2021
DOI:
10.5194/cp-17-2119-2021-supplement
DOI:
10.5194/cp-17-2119-2021-corrigendum
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2217985-9
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