Pleistocene Volcanisms South-west of Cape Farewell, Greenland II: Geological Evidence

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] a ridge-ridge-ridge triple junction existed South of Cape Farvel, Greenland. Here, 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. Seismic data show a basement high piercing the seafloor in the southwestern part of the area while in the northwestern part of the Eirik Ridge a disturbance of the sedimentary sequences up to the seafloor can be observed. Parasound profiles document a number of packages with limited lateral extension within the normal background sedimentation adjacent to the ridge. A 9.96 meter long gravity core (57°33.44’N, 48° 37.02’W) sampling two of these packages was taken east of the structure. The core sampled a number of fining upward sequences indicating sediment transport. Dating of the sediment packages using biostratigraphy indicates that these are out of sequence. Earliest Pleistocene (Olduvai) sediments are over- and underlain by late Pleistocene ones. This suggests that the uplift of the basement led to a vertical displacement of sediment packages and redeposition during the late Pleistocene significantly later than any reported volcanism in the area. 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.