How magnetics and granulometry of continental margin sediments reflect terrestrial and marine environments of South America and West Africa

Abstract

Continental margins are supplied by terrigenous clastic, as well as by biogenic marine sediments and, thus, act as natural archives for various environmental conditions. This thesis delineates sediment-distribution patterns off SE South America (20-55 deg. S) and NW Africa (14-17 deg. N) mainly based on rock-magnetic properties supplemented by clastic grain-size distributions, major-element concentrations, planktic and benthic foraminiferal assemblages, as well as stable-isotope signatures obtained from surface and down-core sediment samples. These investigations, spanning the last 19 kyr, reveal insights about prevalent climatic conditions on land (i.e., intensities of South American Monsoon System&Southern Westerly Wind Belt, or North-African Harmattan&trade winds) with impacts on major terrestrial sediment sources and transport paths. However, they also enable to draw conclusions about marine environmental conditions linked to ocean-current systems (i.e., Brazil&Malvinas Currents).