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Site U13181

Expedition 307 Scientists2

Background and objectives

Site U1318 (proposed Site PORC-2A; 51°26.16′N, 11°33.0′W; 423 m water depth) is located on the eastern slope of Porcupine Seabight on the southwest continental margin of Ireland (Fig. F1) and is upslope from the Belgica mound province, including Challenger Mound. Sediments were expected to consist of silty clay and nannofossil- and microfossil-bearing ooze intercalated with sandy and terrigeneous sediments, possibly with diagenetic carbonates.

The three main seismic units, P1, P2, and P3, are encountered at Site U1318 (Fig. F2) (see the “Site U1316” chapter). Unit P1 is characterized by a series of parallel, continuous layers of low amplitude. At this site, the base of Unit P1 is formed by a series of sigmoid-shaped bodies. Unit P2 is characterized by a nearly transparent acoustic facies on top of the erosional unconformity bounding Units P1 and P2. Only a few sets of continuous, relatively high amplitude reflectors are observed inside Unit P2. The uppermost seismic Unit P3, characterized by slightly upslope migrating wavy parallel reflectors, represents Quaternary drift deposits (Von Rooij et al., 2003).

The principal objective at Site U1318 was to recover the sediments from the three seismic units (P1–P3) of the southern Belgica mound province. Complete data from the seismically low amplitude layer (Unit P2) would allow refinement of the paleoenvironmental history before initiation of Challenger Mound.

1 Expedition 307 Scientists, 2006. Site U1318. In Ferdelman, T.G., Kano, A., Williams, T., Henriet, J.-P., and the Expedition 307 Scientists. Proc. IODP, 307: Washington, DC (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/​iodp.proc.307.105.2006

2 Expedition 307 Scientists’ addresses.

Publication: 14 October 2006
MS 307-105