Evidence for Pleistocene Volcanism Southwest of Cape Farvel I: Seismic Evidence

South of Cape Farvel, Greenland, a ridge-ridge-ridge triple junction existed from the time of break-up along east Greenland at ~56 Ma to the cessation of spreading in the Labrador Sea at ~40 Ma [Nielsen, et al., 2002]. There, the Eirik Ridge forms a bathymetric feature and, according to Nielsen et al. [2002], was created as a volcanic plateau of similar age close to the triple junction. Geophysical and geological data collected on cruise MSM 12/2 onboard RV Maria S. Merian in June/July 2009 shed new light on the more recent development of this structure.2000 km of high resolution seismic reflection data present a detailed image of the sedimentary sequences down to basement and the uppermost structures within basement. Additionally to the volcanic plateau in the northwestern part of the Eirik Drift our data show a number of narrower basement highs (10-15 km at their base), which rise up to 1500 m above the surrounding basement. The sedimentary sequences on top of those basement highs are significantly disturbed and disrupted. In the southwestern part of the area a basement high pierces the seafloor while in the northwestern part of the Eirik Ridge a disturbance of the sedimentary sequences up to the seafloor can be observed. Additionally, we identify faults within the sedimentary sequences on top of the northwestern volcanic plateau, which in places rise up to the seafloor. This implies a late syn- or post-sedimentary deformation, which we interpret as evidence for magmatic activity affecting this area during the last few million years.The seismic data will be presented together with a discussion of a possible origin of the proposed Pleistocene magmatism.Nielsen, T. K., et al. (2002), Contrasting rifted margin styles south of Greenland: implications for mantle plume dynamics, Earth and Planetary Science Letters, 200, 271-286