Deep Mantle Component and Continental Crust Remobilization in the Source of Vesteris Seamount, East Greenland Margin.

Vesteris Seamount is a large Quaternary intraplate submarine volcano in the SW Greenland Sea, about 1,000 km NE of Iceland and 300 km NW of the Mohn's spreading ridge, whose mode of formation remains unsolved. We present geochemical data for new samples dredged from the Vesteris edifice, including major, trace elements and Sr‐Nd‐Pb‐Hf isotopes. The isotopic characteristics of the alkaline lavas, covering the basanite/tephrite to benmoreite range, indicate the involvement of depleted and enriched mantle components. The source is dominated by the depleted mantle (85%–90%) and a deep enriched component possibly supplied by the Iceland Plume (IP) (10%–15%). Additional source enrichment was due to recycled crust and sub‐continental lithospheric mantle, as suggested by Hf isotopes (0.283147 ± 0.000005) measured for the first time in Vesteris lavas and by a decoupling in Pb isotopes evidenced by relatively low‐radiogenic 207Pb/204Pb (15.510) and high‐radiogenic 208Pb/204Pb (38.554) with respect to the Northern Hemisphere Reference Line. We interpret the geochemical results using existing knowledge about the regional lithospheric and upper mantle structure. Our findings suggest that a deep (ca. 420–320 km) mantle anomaly, with seismological characteristics of the Iceland mantle plume, extends from East Greenland to the north of Jan Mayen Fracture Zone. The regional lithospheric thinning toward the Greenland Basin enabled the melting events that produced the Vesteris seamount. This lateral NNE‐directed flow lobe of the Iceland plume may have carved and transferred enriched components from the continental lithospheric margin of Greenland north of Scoresby Sund toward the Vesteris source. Plain Language Summary: This study investigates the formation of Vesteris Seamount, the largest submarine volcano in the Greenland Sea, situated north of Iceland and the Jan Mayen Fracture Zone and east of the Greenland continental margin. Given the isolated position of Vesteris, it is challenging to define its formation mechanisms and the mantle source. This study presents geochemical data by analyzing samples dredged from Vesteris' flanks. A deep mantle component, similar to the Iceland plume, seems to contribute to the mantle source of Vesteris magmas and the regional depleted asthenosphere. However, our results also suggest a contribution of an enriched component. This could be the sub‐continental mantle lithosphere (SCLM) and a crustal component. These components could have been transported from the Northeastern Greenland Margin, North of Scoresby Sund, along with the mantle flow. Subsurface seismic tomography images indicate an NNE‐directed flow lobe from the mantle plume under Iceland. We suggest that this setting played an important role in the seamount formation and explain the isotope signatures of SCLM‐like and crustal components by deep mantle carving of the western Greenland margin. Key Points: New volcanic rock samples are dredged from Vesteris Seamount in the SW Greenland SeaSample analysis shows geochemical evidence of deep mantle component and continental crust remobilizationMelting underneath Vesteris was enhanced by steep lithospheric thickness change that allowed channeling of the Iceland plume branch [ABSTRACT FROM AUTHOR]