Origin and composition of hydrothermal sediments at Aurora Vent Field, southern Gakkel Ridge (82.9°N)

The increasing number of active vents discovered worldwide, and new observations of basin-scale plumes suggest an underestimated role of hydrothermal systems in the ocean element cycling. This is especially true for slow-ultraslow spreading ridges which represent ca. 50% of the global mid-ocean ridge system and have only recently been recognized to host hydrothermal activity. Here, we present new data from sediment cores collected during HACON19 and HACON21 cruises at Aurora Vent Field, Arctic Ocean. We describe and interpret the hydrothermal signals recorded in the sediments at various distances from the active vents, based on core scanning (X-Rays, XRF, Multisensor scanner), and mineralogical and geochemical (XRF%) analyses on discrete samples. Metalliferous sediments surround the vents, with predominance of sulfide and (hydr)oxide minerals. Plume deposits are found several kilometers from the active vent, and their stratigraphic distribution in the longer gravity cores provided insights into the history and dynamics of vent activity since the last Ice age.

Acknowledgments: this research was supported by HACON project (Research Council of Norway grant No. 274330) and AKMA project (Research Council of Norway grant No. 287869).