Seismic reflection data of the Eirik Drift: A first step to decipher the Neogene development of the Western Boundary Undercurrent (WBUC)

• Main Authors: Mueller-Michaelis, Antje, Uenzelmann-Neben, Gabriele
• Format: Conference Object
• Language: unknown
• Published: 2012
• Subjects: Davis Strait; Greenland; Ice Sheet; Labrador Sea
• Online Access: https://epic.awi.de/id/eprint/25708/; https://epic.awi.de/id/eprint/25708/1/Abstract_IODP_Mueller_Michaelis.pdf; https://hdl.handle.net/10013/epic.38703; https://hdl.handle.net/10013/epic.38703.d001

The Eirik Drift off the southern tip of Greenland contains sedimentary records since the Miocene. This archive of depositional processes has been shaped by the Western Boundary Undercurrent (WBUC), the Greenland ice sheet, and material input from the Labrador Sea through the Davis Strait. The WBUC is a main contribution to the lower branch of the global Thermohaline Circulation, which determines the world's climate. Therefore, changes in strength and direction of the WBUC are closely connected to climate changes. The high-resolution multichannel seismic reflection data network collected during RV Maria S. Merian cruise MSM 12/2 connected ODP Leg 105 Site 646 and IODP Expedition 303 Sites U1305, U1306, and U1307 (Fig. 1). The seismic reflection data were incorporated with geological information from the ODP and IODP sites to deduce information on the development of the WBUC as well as the dimensions and expansion/retreat of the Greenland ice sheet and a much clearer understanding of the evolution of the climate southwest of Greenland. After correlating synthetic seismograms based on density and P-wave velocity data from ODP Leg 105 Site 646 and IODP Expedition 303 Sites U1305, U1306, and U1307 with the processed seismic reflection data we identified four seismic units and the reflectors defined by Arthur et al. (1989) (Table 1; Fig. 2). Figure 2 shows seismic profile AWI-20090004 (red dashed line in Fig. 1) as an example with the location of ODP Leg 105 Site 646 and the identified reflectors and units (Table 1). Tracking of both reflectors and units leads to information about the redistribution of the WBUC in the vicinity of the Eirik Drift during the Neogene.Seismic unit IV (SU IV; > 7.5 Ma) is bounded by the acoustic basement (brown) and the reflector doublet R3/R4 (blue). SU IV shows a high sediment accumulation at the main drift mound in the east (CDP 66-5000), more than twice as high as the more uniform thickness in the west (CDP 5000-12780). This indicates a strong deep current influence in northward ...