New ice core insights into the sources and sulfur emission of the largest Common Era eruptions: a case study of eruptions from 680-690 CE

Cryptotephra fingerprinting is the most robust method for linking volcanic sulfate deposits in polar ice cores with their eruptive source. Advances in the detection and geochemical characterization of extremely fine cryptotephra deposits (e.g., volcanic glass shards <10 μm in size) have enabled the source identification of increasingly distal eruptions preserved in Greenland and Antarctic cores. These developments improve constraints on eruption timing, sulfur loading, and ash dispersal, allowing reconstruction of detailed volcanic histories assessing the provenance and recurrence rate of events with global, societal consequences.

Here, we investigate evidence for volcanic eruptions occurring during the interval 680-690 CE, preserved in Greenland ice core Tunu2013, and Antarctic ice core B53. This targeted time period includes the 5^th largest volcanic stratospheric sulfur injection of the Common Era (last 2000 years), deposited as a contemporaneous sulfur peak in both hemispheres in 682 CE. Previous hypotheses have suggested three closely timed VEI 5-6 eruptions from New Britain Island, Papua New Guinea, as the most likely source candidates for this sulfur deposit.

By combining cryptotephra geochemical fingerprinting with sulfur isotope analysis, we provide new insights into the sources, plume height, sulfur emission and tephra transport of major eruptions occurring between 680-690 CE, including the 682 CE event and the Newberry Pumice 687 CE eruption. These results contribute to ongoing efforts to identify the sources of the largest Common Era sulfur deposits in polar ice cores and build detailed records of volcanic eruptions associated with global climate perturbations and ultra-distal ash dispersal.