Description: Die wirtschaftlichen Erfolge der Explorationsarbeiten auf Kohlenwasserstoffvorkommen in den Schelfgebieten veranlaBten bereits Ende der sechziger Jahre eine Intensivierung der geowissenschaftliehen Forschungsarbeiten an den Kontinentalrändern der Ozeane. Forschungsinstitutionen und Erdölindustrie beteiligen sich an diesen Arbeiten. Ziel dieses Berichtes ist es, an Hand von typischen Beispielen Anhaltspunkte zu gewinnen, ob jenseits der Schelfkante in den tieferen Teilen der Ozeane Kohlenwasserstoffvorkommen auftreten können. Nach den bisherigen Erkenntnissen entsprechen die strukturellen Verhältnisse im Untergrund von Kontinentalabhang und -anstieg oft denen unter dem angrenzenden Kohlenwasserstoff-führenden Schelf. Erdölmuttergesteine sind auch jenseits der Schelfkante bekannt geworden, Speichergesteine sind zu vermuten. Es kann daher im Prinzip auch dort mit Kohlenwasserstoffvorkommen gerechnet werden. Mehrere Konzessionen erstrecken sich über die Schelfkante ins Meer hinaus und erste Aufschlußbohrungen sind bereits in tieferen Wassergebieten der Ozeane abgeteuft worden. Hydrocarbon resources beyond the shelf break? - Based on encouraging results of oil and gas exploration ·activities in the shelf regions of the oceans, geoscientific investigations of the continental margin have considerably intensified since the end of the sixties. Research institutions and oil industry are interested in these investigations. The aim of this paper is to find out, by critical evaluation of some typical examples, wheth•ar there are areas beyond the shelf break that are probably prospective for hydrocarbon deposits. Source rocks have become known in the underground of the deep-water regions, reservoir rocks can be infered. According to our present knowledge, the geological conditions prevailing in the deep underground of the continental slope and rise often correspond to those of the bordering shelf area where oil or gas fields occur. Therefore, hydrocarbon deposits can also be expected beyond the continental shelf. Several oil concessions have already been granted for fields extending beyond the continental shelf and some wild cats have also been drilled there.

Description: The different types of sediments in the Indian Ocean and their areal distribution are described first. Following this their calcium carbonate content is discussed. The origin of these different deposits depends on the character and amount of the ter- rigenous detritus, on the nature of the organic substances supplied to the sediment, and on the physical and chemical properties of the ocean water which influence the car- bonate content of the deposits. The varied influence of these factors in the individual ocean regions permits the interpretation of the large-scale distribution of the deep-sea sediments and of their carbonate content on the bottom of the Indian Ocean. On the basis of the results of investigations by the "Meteor" Expedition of the sediments of the equatorial Atlantic Ocean it is possible to explain the stratigraphic relationships of the pelagic sediments of the Indian Ocean in their major features and to gain some knowledge of its history back to the last glacial period. This knowledge agrees with ob- servations in the equatorial Atlantic Ocean, thus giving a wider regional significance to the conclusions based on the data from the Atlantic Ocean