Description: This study is based on a reconstruction of the paleogeographic and paleobathymetric history of the South Atlantic and on a standardized set of sediment and biostratigraphic data from all Deep Sea Drilling Project sites. Standard data sets used are the lithologic description, biostratigraphic age, CaCO3 content, carbonate and carbonate-free sedimentation rates corrected for compaction, and hiatus distribution. For each site the subsidence history has been determined. Paleoceanographic variables used are the spatial and temporal lithofacies distribution, history of calcite compensation depth, surface fertility and lyocline, erosional events, and special lithologies (black shales). During its early history the South Atlantic consisted of a narrow rift divided by the Rio Grande Rise- Walvis Ridge barrier into a restricted northern and an open (to the southern ocean) southern basin. In the northern basin, evaporites are the earliest known marine sediments (Aptian) while more normal pelagic deposits formed in the southern basin. Free circulation of surface water between the southern ocean and the North Atlantic became possible late in the Mesozoic or in the early Cenozoic, and deep circulation (below 3 km depth) paths were open from north to south by the early Cenozoic. During the early and middle Mesozoic the South Atlantic had its own oceanographic character with dominantly terrigenous sedimentation and two anoxic black mudstone phases (Albian and Santonian) probably resulting from a strong oxygen minimum in mid-water caused by either excess surface fertility or old, slow moving bottom water. In the late Cretaceous the South Atlantic became part of the world ocean system and global events have overshadowed local ones since that time. After the early phase of rapid sedimentation of terrigenous material, the depositional history has been in- fluenced mainly by the increasing width and water depth of the basin and by fluctuations of the level and intensity of carbonate dissolution. At the Eocene/Oligocene boundary, the onset of a deep water circulation dominated by a cold circum-polar source of surface water is clearly marked by erosional events, a sharp drop of the calcite compensation depth and the arrival of biogenic siliceous oozes in the Argentine Basin.

Description: Summary of Ilse Seibold's vita Ilse Seibold, née Usbeck, was born May 8, 1925 in Breslau, Silesia, and went to school in Halle/Saale during WW2. She started her studies of geology and paleontology at the University of Halle and at the Humboldt University in Berlin, and later at the University of Tübingen, where she received her doctorate as micropaleontologist in 1951 with Otto Schindewolf as her supervisor. She remained active as productive scientist over many decades. In 1952, she married Dr. Eugen Seibold, who in 1958 became professor at Kiel University, founded one of Europe's most important institutes for marine geology, and later became president of the German Science Foundation (DFG), and subsequently of the European Science Foundation (ESF). Being a scientist herself Ilse Seibold soon evolved to a deeply reflective insider of geological sciences. She followed her husband during his scientific career from his appointments in Tübingen, Bonn, Karlsruhe, Kiel, to Bonn and Strasbourg/Freiburg i.Br. She accompanied Eugen on his sabbatical leave at Scripps Institution of Oceanography in La Jolla, CA. She participated in countless international scientific meetings. Together with Eugen she published many papers that document her independence and autonomy as scientist. She gained deep insights into the origins of the geosciences and their historical evolution, up to the ideas of fine arts. We are happy that she documented in her publications a broad range of her scientific and distinguished-humane impressions.

Description: Plankton pump samples and plankton tows (size fractions between 0.04 mm and 1.01 mm) from the eastern North Atlantic Ocean contain the following shell- and skeleton-producing planktonic and nectonic organisms, which can be fossilized in the sediments: diatoms, radiolarians, foraminifers, pteropods, heteropods, larvae of benthic gastropods and bivalves, ostracods, and fish. The abundance of these components has been mapped quantitatively in the eastern North Atlantic surface waters (Fig. 4) in October - December 1971. More ash (after ignition of the organic matter, consisting mostly of these components) per cubic meter of water is found close to land masses (continents and islands) and above shallow submarine elevations than in the open ocean. Preferred biotops of planktonic diatoms in the region described are temperate shallow water and tropical coastal upwelling areas. Radiolarians rarely occur close to the continent, but are abundant in pelagic warm water masses, even near islands. Foraminifers are similar to the radiolarians, rarer in the coastal water mass of the continent than in the open ocean or off oceanic islands. Their abundance is highest outside the upwelling area off NW Africa. Molluscs generally outnumber planktonic foraminifers, implying that the carbonate cycle of the ocean might be influenced considerably by these animals. The molluscs include heteropods, pteropods, and larvae of benthic bivalves and gastropods. Larvae of benthic molluscs accur more frequently close to continental and island margins and above submarine shoals (in this case mostly guyots) than in the open ocean. Their size increases, but they decrease in number with increasing distance from their area of origin. Ostracods and fish have only been found in small numbers concentrated off NW Africa. All of the above-mentioned components occur in higher abundances in the surface watet than in subsurface waters. They are closely related to the hydrography of the sampled watet masses (here defined through temperature measutements). Relatively warm water masses of the southeastern branches of the Gulf Stream system transport subtropical and southern temperate species to the Bay of Biscay, relatively cool water masses of the Portugal and Canary Currents carry transitional faunal elements along the NW African coast southwards to tropical regions. These mix in the northwest African upwelling area with tropical faunal elements which are generally assumed to live in the subsurface water masses and which probably have been transported northwards to this area by a subsurface counter current. The faunas typical for tropical surface water masses are not only reduced due to the tongue of cool water extending southwards along the coast, but they are also removed from the coastal zone by the upwelling subsurface water masses carrying their own shell and skeleton assemblages. Tropical water masses contain much more shelland skeleton-producing plankters than subtropical and temperate ones. The climatic conditions found at different latitudes control the development and intensity of separate continental coastal water mass with its own plankton assemblages. Extent of this water mass and steepness of gradients between the pelagic and coastal environment limit the occurrence of pelagic plankton close to the continental coast. A similar water mass in only weakly developed off oceanic islands.

Description: High concentrations of fine-grained and probably wind-blown quartz with an Australian provenance have been mapped in Holocene sediments in the southwest Pacific. During the last glacial maximum a narrow zone of high eolian input, as reflected in a higher abundance of quartz, extended more than 20° longitude farther east than today. This zone, which was significantly farther north than at present, is centered around lat 30° S but curves around the northern tip of New Zealand. These quartz distributions imply that the westerly winds that blew the airborne quartz over the southwest Pacific had shifted considerably to the north under the influence of intensified atmospheric circulation during the last glacial maximum.