IODP Proceedings    Volume contents     Search



During Integrated Ocean Drilling Program (IODP) Expedition 339, Mediterranean Outflow, IODP Site U1387 (36.8˚N, 7.7˚W; 559 m water depth; Fig. F1) was drilled into the contourite deposits of the Faro Drift (see the Expedition 339 summary chapter [Expedition 339 Scientists, 2013a). The Faro Drift was built up by activity of the Mediterranean Outflow Water (MOW), the upper core of which is directly influencing Site U1387 (see the Site U1387 chapter [Expedition 339 Scientists, 2013b]; Voelker et al., 2015). Present-day surface waters in the region are of subtropical origin and transported by the eastern branch of the Azores Current (far offshore) and the eastbound Gulf of Cadiz Slope Current, an open-ocean current located along the southern Iberian margin (Peliz et al., 2009) (Fig. F1).

At Site U1387, three holes were drilled. Holes U1387A and U1387B were drilled with the advanced piston corer (APC) and extended core barrel (XCB) coring systems, and Hole U1387C was drilled with the rotary core barrel (RCB) system. The XCB-drilled cores, starting with Cores 339-U1387A-7X and 339-U1387B-6X, show persistent coring disturbances, (i.e., biscuits) (see the Site U1387 chapter [Expedition 339 scientists, 2013b]). During the expedition, a shipboard splice was constructed based on magnetic susceptibility and natural gamma radiation (NGR) data at resolutions of 2.5 cm and 20 cm, respectively. Deeper than ~155 meters composite depth (mcd), the shipboard splice is based on the combination of the magnetic susceptibility and NGR signals because the magnetic susceptibility data had weak signals and might be anomalous because of the biscuiting (see Stratigraphic correlation in the Site U1387 chapter [Expedition 339 Scientists, 2013b]).

Within the Surface and Mediterranean Outflow Water Dynamics in the Gulf of Cadiz during the Pleistocene (MOWCADYN) project, a multiproxy study was performed to reconstruct surface water and MOW changes in the interval between marine isotope Stages (MISs) 16 and 48, encompassing samples from Sections 339-U1387B-18X-3 through 339-U1387C-8R-3 (i.e., between 171.68 and 389.19 mcd). However, when the results of the stable isotope analyses, among others, became available, it was evident that mismatches occurred in the proxy records at several splice transitions. Additional off-splice samples were therefore analyzed to increase/maximize the overlap between cores at the splice transitions, leading to the revised splice presented here.