Summary

The Zaire deep-sea fan is a large mud-dominated system fed mainly by the Zaire (Congo) River. A submarine canyon deeply incised into the outer estuary funnels part of the river’s high suspended load directly out to the deep sea. Sediment is also contributed to the fan via slumping and debris-flows initiated on the upper slope. A number of 11–17 m long piston cores have been collected from this part of the SE Atlantic Ocean, and three of these are described in detail in terms of structure, texture and composition. Four sediment facies are recognized: (1) turbidite muds with mainly T_E1, T_E2 and T_E3 structural divisions (after Piper 1978); (2) pelagic and hemipelagic biogenic muds; (3) homogeneous uniform muds that probably result from slow settling of dilute suspensions; and (4) debris-flow deposits. There are marked differences in facies distribution, turbidite thickness and organic carbon content between the upper and outer regions of the fan.