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Abstract
Eirik Drift is a detached giant elongated drift which extends a total length of 360 km, located off the southern margin of Greenland, approximately 100 km south of Cape Farewell, Greenland in the North Atlantic Ocean. Eirik Drift is controlled by the influence of deep contour currents resulting from the movement of the deep Western Boundary Undercurrent (WBUC). The WBUC is a dominant constituent of North Atlantic Deep Water (NADW), the lower limb of the global thermohaline circulation (THC) system, which transports sediments, nutrients, and temperature regimes across the Atlantic Ocean. Understanding the origins, distribution, and development of Eirik Drift is critical to reliably placing proxy data into a larger context of sedimentation, ocean circulation, global climate and using these histories as analogs of recent changes in global climate. This study examined the seismic stratigraphy of Eirik Drift using multi-channel seismic (MCS) profiles collected in the summer of 2002 during cruise KN166-14 of the R/V Knorr and tied it to the lithology, sedimentation rates, and downhole data of four Ocean Drilling sites: Ocean Drilling Program (ODP) Leg 105 Site 646, and International Ocean Discovery Program (IODP) Expedition Sites U1305, U1306 and U1307. This analysis concludes that drift building began at 7.5 Ma and continues to the present. The drift’s morphology shows significant sedimentation and drift building occurred throughout the Pliocene, then slowed during the Pleistocene, as shown through mapped patterns of sediment accumulation in time and space. Over this time, the WBUC has migrated with varying intensity (i.e., modifications in velocity and/or and buoyancy relating to climate regimes), modifying the shape and distribution of the drift, due to measured changes in sediment supply, ocean circulation, and atmospheric conditions. This finding is consistent with other measurements and models of the history of WBUC and North Atlantic Ocean circulation and atmospheric conditions.
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