Diagenetic imprints on magnetic mineral assemblages in marine ...

Chapter 2.2
boundary of the Argentine Basin. Sedimentation in this area is controlled by two main
processes: gravity-controlled sediment transport and strong current circulation (Ewing and
Leonardi, 1971; Klaus and Ledbetter, 1988). Terrigenous input originates from the
numerous fluvial tributaries along the coast of Argentina and Uruguay (Iriondo, 1984;
Piccolo and Perillo, 1999). The sediments are transported directly down-slope along the
western margin of the Argentine Basin by gravity-controlled processes (Ewing et al., 1971;
Biscay and Dasch, 1971; Klaus and Ledbetter, 1988; Sachs and Ellwood, 1988; Romero
and Hensen, 2002; Hensen et al., 2003). These gravity-driven mass transports, such as
debris flows and turbidity currents, are the main pathways of sediment supply into the
deeper basin. The second important process controlling the sedimentation in this area is
the action of strong currents along the continental margin. The currents in the upper water
Fig. 1. Location map of the study area offshore of the Rio de la Plata. Arrows indicate simplified
pathways of the main currents (solid line presents the surface-water currents MC (Malvinas
Current) and BC (Brazil Current), and the lower-level and bottom-water currents are marked by
dashed lines: NADW = North Atlantic Depth Water; AABW = Antarctic Bottom Water.
column are the southward flowing Brazil Current and the northward flowing Malvinas
(Falkland) Current (Peterson and Stramma, 1991). These two currents meet in the Brazil
Malvinas Confluence (BMC), located in front of the Rio de la Plata. The confluence of the
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