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doi:10.2204/iodp.proc.303306.213.2009

Site location and regional setting

Site U1314 was cored at 2820 m water depth using the R/V JOIDES Resolution during IODP Expedition 306. The site is located on the southeastern flank of the Reykjanes Ridge in an area known as the southern Gardar Drift in the subpolar North Atlantic (56.36°N, 27.88°W) (Fig. F1). Its deposition is believed to be linked to changing deep-ocean circulation patterns in the North Atlantic (Dickson and Brown, 1994) and its shape and location controlled by pre-existing topography and sediment supply (McCave and Tucholke, 1986).

Site U1314 is situated close to the ice-rafted debris (IRD) belt for high-resolution monitoring of North Atlantic Deep Water (NADW) variability and ice sheet instability (see the “Expedition 306 summary” chapter; Stein et al., 2006). The site is complementary to Ocean Drilling Program (ODP) Sites 983 (60°24.2′N, 23°38.4′W, 1985 m water depth) and 984 (61°25.5′N, 24°04.9′W, 1648 m water depth) drilled south of Iceland on the northern part of the Gardar and Bjorn drifts during ODP Leg 162 (Jansen, Raymo, Blum, et al., 1996), which were selected for monitoring intermediate water circulation (Channel et al., 1997; see the “Expedition 306 summary” chapter). Sites 983 and 984 have produced high-resolution climatic and geomagnetic records (e.g., Raymo et al., 1998; Channell et al., 1998; Flower et al., 2000).

Three holes were drilled and cored at Site U1314 using the JOIDES Resolution’s advanced hydraulic piston corer system (see the “Site U1314” chapter). The maximum depth reached was 279.91 meters below seafloor in Hole U1314B. The holes were correlated aboard ship using sediment core physical properties. The obtained correlations were used to construct a composite section (or splice) for the site, providing an optimal record of the sedimentary sequence. The spliced section was completed to 281 meters composite depth (mcd). Shipboard magnetic and biostratigraphic analyses suggest that the oldest sediments recovered were deposited close to 3 m.y. ago (see the “Site U1314” chapter).

Late Pleistocene and Holocene sediments at Site U1314 consist predominantly of pelagic sediments containing well-preserved biogenic components including calcareous (e.g., nannofossils and planktonic foraminifers) and siliceous (e.g., diatoms and radiolarians) microfossils and a lower content of terrigenous components such as clay, quartz, and dark minerals. Changes in the relative proportions of these two sediment types likely reflect variable depositional rates, sea-surface productivity, and sediment provenance (see the “Site U1314” chapter).

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