Major element concentration and radionuclides of equatorial Pacific deep-sea sediments

DOI

The (231Pa/230Th)xs,0 records obtained from two cores from the western (MD97-2138; 1°25'S, 146°24'E, 1900 m) and eastern (ODP Leg 138 Site 849, 0°11.59'N, 110°31.18'W, 3851 m) equatorial Pacific display similar variability over the last 85000 years, i.e. from isotopic stages 1 to 5a, with systematically higher values during the Holocene, isotopic stage 3 and isotopic stage 5a, and lower values, approaching the production rate ratio of the two isotopes (0.093), during the colder periods corresponding to isotopic stages 2 and 4. We have also measured the 230Th-normalized biogenic preserved and terrigenous fluxes, as well as major and trace elements concentrations, in both cores. The (231Pa/230Th)xs,0 results combined with the changes in preserved carbonate and opal fluxes at the eastern site indicate lower productivity in the eastern equatorial Pacific during glacial periods. The (231Pa/230Th)xs,0 variations in the western equatorial Pacific (WEP) also seem to be controlled by productivity (carbonate and/or opal). The generally high (231Pa/230Th)xs,0 ratios (>0.093) of the profile could be due to opal and/or MnO2 in the sinking particles. The profiles of (231Pa/230Th)xs,0 and 230Th-normalized fluxes indicate a decrease in exported carbonate, and possibly opal, during isotopic stages 2 and 4 in MD97-2138. Using 230Th-normalized flux, we also show that sediments from the two cores were strongly affected by sediment redistribution by bottom currents suggesting a control of mass accumulation rates by sediment focusing variability.

Supplement to: Pichat, Sylvain; Sims, Kenneth W W; Francois, Roger; McManus, Jerry F; Brown Leger, Susan; Albarède, Francis (2004): Lower export production during glacial periods in the equatorial Pacific derived from (231Pa/230Th)xs,0 measurements. Paleoceanography, 19(4), PA4023

Identifier
DOI https://doi.org/10.1594/PANGAEA.755548
Related Identifier IsSupplementTo https://doi.org/10.1029/2003PA000994
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.755548
Provenance
Creator Pichat, Sylvain; Sims, Kenneth W W ORCID logo; Francois, Roger; McManus, Jerry F ORCID logo; Brown Leger, Susan; Albarède, Francis
Publisher PANGAEA
Publication Year 2004
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 5 datasets
Discipline Earth System Research
Spatial Coverage (-110.520W, -0.233S, 146.236E, 1.420N); North Pacific Ocean; Ontong Java Plateau
Temporal Coverage Begin 1991-06-07T23:25:00Z
Temporal Coverage End 1991-06-10T12:04:00Z