Report and preliminary results of METEOR Cruise 34/1. Cape Town - Walvis Bay, 03.01.1996 - 26.01.1996

Abstract

Until today the eastern South Atlantic is poorly covered by Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) drill holes. Only DSDP Sites 364 and 365 on the southwest African continental margin off Angola, DSDP Sites 360 and 361 in the southern Cape Basin as well as several sites in the Walvis Ridge area have been studied in more detail. Nevertheless, high resolution information remains sparse for the Cenozoic and in particular the Neogene sedimentation history of the region. Modern high quality coring techniques have not yet been applied and data sets relevant to resolve the development and variability of the Benguela Current system since Miocene times are hence still fragmentary. Prime objective of the first leg of R/V METEOR Cruise M 34 was a pre site survey in various parts of the Cape Basin which previously had been identified as adequate target areas to reconstruct the paleoceanographic evolution of the Benguela Current and related upwelling systems from the sedimentary deposits. Seismic and echographic measurements along a series of profiles and sampling of surface sediments are to provide further basic information for subsequent deep coring operations by the international Ocean Drilling Program. The University of Bremen is presently in charge to scientifically prepare this project entitled 'Neogene history of the Benguela Current and Angola/Namibia Upwelling System' which is expected to take place as ODP Leg 175 in late 1997. With the present investigations still lacking data sets are collected at the South African and Namibian continental margin after a complete site survey has been performed in the Angola Basin between 5 and 17 S during Cruise SO 86 with R/V SONNE. For three working areas, the Orange fan and the southern and northern provinces of the Namibian upwelling complex, high resolution digital seismic and echographic recordings with crossing lines wherever necessary are planned to secure a sufficient data basis for the accurate definition of drilling locations. Surface sediments from the immediate vicinity of proposed drilling locations and other sites of strategic interest for the late Quaternary paleoceanographic development are recovered with conventional wireline coring techniques and subsequently analyzed using physical, isotopic, micropaleontological and sedimentological methods. (orig.)SIGLEAvailable from TIB Hannover: RO 7630(77) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman