Origin of the 1458/59 CE volcanic eruption revealed through analysis of glass shards in the firn core from Antarctic Vostok station

The 1458/59 CE volcanic event, among the largest in the last millennium, is primarily attributed to the Kuwae volcano in Vanuatu. However, a recent study suggests the Reclus volcano in southern Patagonia, Chile, as an alternative source. Here, we assess the hypothesis by examining unpolished, micron-sized glass shards from the 1458/59 CE cryptotephra in the Antarctic Vostok Station firn core. Results reveal a bimodal composition of dacitic and rhyolitic shards, linked to Kuwae and Reclus, respectively. Antarctic ice core records also exhibit a two-stage pattern of ash deposition: coarse ash from nearby volcanoes followed by finer ash transported over long distances, implying concurrent eruptions. Nevertheless, discrepancies in composition between observed rhyolitic shards and existing Reclus data, combined with no recorded Reclus activity in the 1450 s, suggests the possibility of an undocumented extratropical rhyolitic source. This study underscores the value of glass shard analysis in identifying the origins of volcanic eruptions. The 1458/59 CE cryptotephra in the Antarctic Vostok Station firn core shows a bimodal distribution of dacite and rhyolite, sourced from the Kuwae and potentially an unrecorded southern high-latitude eruption, respectively, implying concurrent events, according to morphological and geochemical analysis of glass shards.