Technical Note 20/4


LEG 175

Benguela Current

Modified from Proposal 354 Submitted By
G. Wefer, V Spieß, U. Bleil, M. Breitzke, K. Gohl, R. Schneider, G. Uenzelmann-Neben

Staff Scientist: Carl Richter
Co-Chief Scientists: Wolfgang Berger & Gerold Wefer

Abstract

Leg 175 proposes to drill nine APC/XCB sites off Angola and Namibia to reconstruct the Cenozoic history of the Benguela Current and the coastal upwelling off Angola and Namibia between 5°S and 32°S. The Angola/Namibia system is one of the great upwelling regions of the world, and extends over a considerable portion of the western margin of South Africa. Like the Peru system, which was studied during ODP Leg 112, it is characterized by organic-rich sediments that contain an excellent record of productivity history, which can be read on a very fine scale. In addition, this environment provides an excellent setting for natural experiments in diagenesis and in the formation of economically important resources such as petroleum and phosphate.

The individual transects reflect examinations of specific"endmember" upwelling environments, which collectively comprise one of the most concentrated centers of ocean productivity. One of the major aims will be to monitor the evolution of the Benguela Current system and its relationship with the onset of Northern Hemisphere and Antarctic glacial cycles. Many of the proposed sites are expected to have high-sedimentation rates, offering an opportunity to develop very detailed paleoceanographic records, and all proposed sites will expand and refine the partial record of the paleoceanographic and paleoclimatic changes since the early Miocene provided by DSDP Sites 362 and 532. Sediments will be largely diatomaceous and carbonate rich clays with variable, and occasionally very high, organic-carbon contents.

To Leg 175 Proposed Site Information

To Leg 176

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