caa a22 4500 477064299 CHVBK 20180405111408.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF02369008 doi (NATIONALLICENCE)springer-10.1007/BF02369008 Geochemistry of a piston core from Ontong Java Plateau (western equatorial Pacific): evidence for sediment redistribution and changes in paleoproductivity [Elektronische Daten] [B. Schwarz, A. Mangini, M. Segl] We discuss geochemical proxies, reflecting processes of primary productivity, CaCO3 dissolution, and sediment redistribution in a piston core (RNDB 74P) from the Ontong Java Plateau. Due to the shallow water depth, biogenic carbonate is well preserved and a very goodδ 18O stratigraphy is available down to isotopic stage 11.230Thex gives evidence that the sediment accumulation pattern is driven mainly by processes of sediment focusing or winnowing. Due to the constant production of230Th in the water column, the bulk sediment accumulation rates could be corrected for the particle rain deriving from the water column above. The230Thex 0/CaCO3 ratio reflects the well-known Pacific CaCO3 preservation pattern with ice growth dissolution spikes and deglacial preservation spikes. The record of the grain size fraction >63 µm supports these results. The downcore concentrations and accumulation rates of barium (Ba) are on a higher level during interglacials and show several peaks. Normalization of Ba with230Thex 0 delivers a more uniform level of the Ba accumulation rates throughout the core. This pattern suggests a constantly higher biological productivity (nearly tenfold) in this area throughout the past 200 kyr compared with an open ocean environment. Barium peaks observed at the climatic transitions 2/1 and 6/5 and in stage 5 are in contrast to a predicted reduction of interglacial productivity at this location. A possible explanation might be the onset of the modern circulation pattern. The transition from Ba-enriched deep water to lower contents in the Atlantic might have resulted in an enhanced deposition of Ba in the Pacific. Springer-Verlag, 1996 Ontong Java Plateau nationallicence Thorium-230 nationallicence Barium nationallicence Productivity nationallicence Lysocline nationallicence Sediment focusing nationallicence Vertical mass accumulation rate nationallicence Schwarz B. Heidelberger Akademie der Wissenschaften, Universität Heidelberg, Heidelberg, Germany aut Mangini A. Heidelberger Akademie der Wissenschaften, Universität Heidelberg, Heidelberg, Germany aut Segl M. Fachbereich Geowissenschaften, Universität Bremen, Bremen, Germany aut Geologische Rundschau Springer-Verlag 85/3(1996-09-01), 536-545 0016-7835 85:3<536 1996 85 531 https://doi.org/10.1007/BF02369008 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02369008 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schwarz B. Heidelberger Akademie der Wissenschaften, Universität Heidelberg, Heidelberg, Germany aut NATIONALLICENCE 700 1- Mangini A. Heidelberger Akademie der Wissenschaften, Universität Heidelberg, Heidelberg, Germany aut NATIONALLICENCE 700 1- Segl M. Fachbereich Geowissenschaften, Universität Bremen, Bremen, Germany aut NATIONALLICENCE 773 0- Geologische Rundschau Springer-Verlag 85/3(1996-09-01), 536-545 0016-7835 85:3<536 1996 85 531 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer