Abstract

The coastal upwelling system of the Peru-Chile Current belongs to the most productive regions in the world oceans. In spite of this remarkable fact only very little is known about the sediment distribution in its southern part off the coast of Chile. To increase the knowledge about this region a multiparameter study of the surface sediment distribution along the Chilean continental slope between 27 and 42 degrees S has been carried out. Detailed analyses of sedimentary data (TOC and carbonate contents, delta(13)C(org), delta(15)N), of the species composition of planktic foraminifera and of the stable isotope composition of the two planktic foraminifera species Neogloboquadrina pachyderma (dex.) and Globigerina bulloides reveal a close relation to environmental conditions in the region. The pattern of a southward increase of surface water productivity known from satellite data is closely reflected in the organic carbon and delta(15)N data. Information about the water mass distribution, especially about varying influences of upwelling waters and warmer Subtropical Surface Waters, can be derived from the species composition of the planktic foraminifera, while the stable isotope data provide additional clues about water mass characteristics. High productivity along the Chilean margin north of 40 degrees S is sustained by coastal upwelling, while further to the south advection of nutrients with the Antarctic Circumpolar Current and a significant riverine input fuel the highest productivity found in the study area. This data set will provide the base for future paleoclimatic and paleoceanographic reconstructions of the Southeast Pacific region. (C) 2000 Elsevier Science B.V. All rights reserved.