Sites 1086 and 1087 are located in the southernmost area of the Cape Basin. South of the proposed transect, the margin becomes too steeply sloped to support undisturbed sediments. The sedimentary records will help in exploring the early history of the Benguela Current in the SCB and in detecting possible Agulhas Current influences (Wefer et al., 1996). The warm-water inflow from the Indian Ocean is thought to be an important component of the global thermohaline circulation system (Gordon, 1986). It has been suggested that much of the North Atlantic Deep Water (NADW) leaving the Atlantic Ocean is balanced by a warm upper layer return flow from the Indian Ocean around the southern tip of Africa, and that this warm-water source turns on and off in tune with the glacial/interglacial fluctuations of NADW production (Berger et al., 1987; McIntyre et al., 1989). A competing model to the "warm-water route," the so-called "cold-water route" (Rintoul, 1991), postulates an inflow from the Pacific Ocean through the Drake Passage.
The sites in the SCB (Sites 1086 and 1087) are expected to deliver information about the supply of warm water from the Indian Ocean, through the Agulhas Retroflection, and from the Subtropical Convergence Zone, which are nearby (Fig. 1). Both warm-water and cold-water eddies can be shed from the retroflection and the front (Fig. 1), but the position of the Subtropical Convergence Zone and the transport by the Benguela Current will be crucial in determining which type of eddy is more likely to reach the sites. These incursions of warm- and cold-water masses will be documented by planktonic indicators (especially by diatoms and foraminifers, but also by nannofossils and radiolarians). One example that is documented for the late Quaternary is the recolonization of the planktonic foraminifer Globorotalia menardii in the Atlantic after regional extinction during glacials (Berger et al., 1985).
Also, the sites are located close to the continent and should detect upwelling signals and signals from continental climates (pollen, clay minerals, and coarser terrigenous matter), as well as sea-level changes.