Reconstruction of the Neogene current system in the area of the Eirik Drift, SW Greenland

Objectives

During Leg MSM 12/2 with RV Maria S. Merian in June/July 2009 both the palaeo as well as the recent sedimentation processes and oceanographic conditions in the area of the Eirik Drift were studied. Proxies determined at recent and sub-recent samples will enable a better interpretation of IODP data and hence lead to a better reconstruction of the long-term development of sedimentation processes, the glacial history, and oceanographic conditions during the Neogene and Quaternary. We have aimed to solve the following questions:

1. What is the detailed structure of the Eirik Drift? Can we distinguish between contouritic and turbiditic deposition? Do the turbiditic deposits lead to information on the extension (frequency and dimension) of the Greenland ice shield? To answer those questions we needed to gather seismic data across the entire Eirik Drift from the shallower parts into the deep sea. The profiles further had to cover the locations of ODP and IODP sites.
2. Can we reconstruct the development of the Western Boundary Undercurrent (WBUC) in this region? Have modifications in the current system been documented in the sediment transport? In what way did those oceanographic modifications affect the sedimentary sequences? Why did the build-up of the Eirik Drift start with a delay of about 1.1 my relative to the oceanographic modifications (i.e. 4.5 Ma)?
3. Can we identify analogies to the build-up and the creation of sediment drifts on the southern hemisphere? Do chronological matches exist between the Eirik Drift and Drift 7 at the Antarctic Peninsula or the Agulhas Drift in the Transkei Basin? Can we identify global climatic and oceanographic events in those drift systems?
4. Can we detect short-term variations of oceanic currents (NADW), sea-ice extent, surface water productivity, and terrigenous input within the upper 15 m of the sedimentary column (Milankovich and sub-Milankovic cycles)? How do those parameters correlate with instabilities of the Greenland ice shield?

      The project comprised geophysical and marin-geological operations in the area of the Eirik Drift.  Streamer, airguns, gravity corer, giant box corer, as well as PARASOUND  and multi-beam systems were used. Seismic reflection profiles were gathered in order to study the sedimentary distribution in relation to the tectonic and oceanographic evolution. Those profiles cover the whole Eirik Drift with the transition into the deep sea. Furthermore, the profiles cover the locations of ODP Leg 105 Site 646 and IODP Expedition 303 Sites 1305, 1306, and 1307.

      The marin-geological programme concentrated on sampling the near-surface sediments (0-15 m) using giant box corer and gravity corer. Undisturbed sediments not affected by e.g. turbidity currents were sampled. Sample locations were picked based on PARASOUND  recordings, which were gathered parallel to the seismic profiling. This saved on ship time. The cores were opened already during the cruise, described and sampled.