Major elements, volatiles, Fe, S speciation, and S isotopes of melt inclusions from Mt Samalas 1257 CE.

The 1257 CE eruption of Mount Samalas (Indonesia) caused the largest stratospheric sulfur injection of the Common Era, as recorded by Greenland and Antarctic ice cores, and led to strong climate perturbations. However, the factors that controlled prodigious excess sulfur buildup at Samalas remain enigmatic. To address this problem, we present sulfur and iron speciation, sulfur isotopes, along with the major elements and volatile concentration in plagioclase-hosted melt inclusions and matrix glasses from 1257 pumice samples.