Major-Minor-Trace Element Analyses and Oceanographic Modeling Confirms Circumpolar Transport of the 1962 Protector Shoal Pumice Raft

Pumice rafts derived from submarine eruptions can remain afloat for months or even years, traveling thousands of kilometers on ocean currents. These natural phenomena disperse marine organisms and provide important evidence for submarine volcanism yet are not fully understood. Here, we describe pumice clasts from Falkland Islands shorelines and use major-minor-trace element analyses to trace their provenance to the 1962 volcanic eruption on Protector Shoal, a large seamount in the South Sandwich Islands, Scotia Sea. Compositional variability between rafted and dredged pumice from Protector Shoal suggests eruptions have varied from explosive to non- or mildly explosive (the latter from lava domes and during neptunian events) and the seamount is volcanically diverse. Oceanographic modeling simulations and historical observations show that clasts from the 1962 eruption reached the Falkland Islands via the Antarctic Circumpolar Current, a journey of ∼20,000 km that took approximately three years. Although oceanographic variability strongly affects modeled transport pathways, in all simulations particles consistently reach the Falkland Islands from Protector Shoal seamount, suggesting a persistent long-distance connection. The results highlight the potential for pumice rafting to disperse non-native, potentially invasive, marine organisms throughout the Southern Ocean as climate warms.

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