New insights into the ? 74 ka Toba eruption from sulfur isotopes of polar ice cores

Abstract. The ?74 ka Toba eruption was one of the largest volcanic events Quaternary. There is much interest in determining impact such a large event, particularly on climate and hominid populations at time. Although has been identified both land marine archives as Youngest Tuff, its precise place ice core record ambiguous. Several sulfate signals have Antarctic Greenland cores span 40Ar/39Ar age uncertainty. Here, we measure sulfur isotope compositions samples from Dome C (EDC) Dronning Maud Land (EDML) high temporal resolution across 11 these potential peaks to identify candidates with mass-independent fractionation (S-MIF), indicative an whose plume reached altitudes or above stratospheric ozone layer. Using this method, several candidate that contain sulfur. We further narrow down based signatures by identifying are due event tropical latitudes. In 73.67 ka, find ever reported magnitude S-MIF polar ice, ?33S value ?4.75 ‰. As there positive correlation between signal recorded eruptive height, could be likely for super-eruption, top height excess 45 km. These results support 73.7±0.3 (1?) estimate eruption, ages our 73.74 ka. Finally, since eruptions occurred transition into Stadial 20, relative timing suggests not trigger Northern Hemisphere cooling time although cannot rule out amplifying effect.