INTRODUCTION

During the Ocean Drilling Program (ODP) Leg 175, 40 holes were drilled at 13 sites along the southwest African margin between 5° and 32°S (Fig. 1). Its primary aim is to reconstruct the Neogene paleocirculation patterns and upwelling history of the Angola-Benguela system. Four distinct regions along the west African coast can be identified based on modern sediment type and composition: (1) the Lower Congo Basin, where clays are predominant; (2) the Angola Basin, which mainly contains silty clays; (3) the Walvis Ridge and Basin, which collect both clays and carbonate oozes; and (4) the Cape Basin, which mainly contains carbonate oozes. The distinctive stratigraphy of each region is attributable to the competing influences of current regime, the proximity to major river systems (both modern and ancient), the proximity to the coast, the water depth, and the relative position to major upwelling centers. The purpose of this paper is to summarize and provide initial sedimentological interpretations of the stratigraphy of each of these regions.

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