Unveiling the Polaris Mud Volcano Complex: A Chain of Mud Volcanoes in the Southwestern Barents Sea

Global estimates on the number of submarine mud volcanoes are highly uncertain, as well as their role in the deep-sea biosphere and methane budgets. Here, we report the discovery of ten mud volcanoes in the Southwestern Barents Sea (440-480 m depth), where only two had been previously known. The new mud volcanoes form flat-topped mounds which are connected to seismic chimneys rooted within the infilling of a buried Pleistocene mega-slide. High-resolution seafloor imagery, collected with a Remotely Operated Vehicle during the EXTREME24 expedition in May 2024, revealed ongoing methane-rich mud expulsion, including mud pools, flows, and associated chemosynthetic fauna. Biostratigraphic and geochemical (gas and oil) analyses of extruded sediments provided insights into the plumbing system. We will present a formation model for the Polaris Mud Volcano Complex, offering new perspectives on the shallow geodynamics of (paleo)glaciated continental margins in relation to mega-slide events.

We acknowledge the projects Advancing Knowledge on Methane in the Arctic (AKMA) (Research Council of Norway grant No. 287869) and EXTREMES (UArctic UA 06/2024) for supporting this research and EMAN7 (Research Council of Norway grant No. 320100) for financing CA position. The Norwegian Offshore Directorate (NOD) partly funded the expedition and analysis. We are grateful to REV Ocean for support during the EXTREME24 cruise and the use of ROV Aurora.