Stable isotope record and sea surface reconstruction of sediment core MD88-770

DOI

Hydrographical changes of the southern Indian Ocean over the last 230 kyr, is reconstructed using a 17-m-long sediment core (MD 88 770; 46°01'S 96°28'E, 3290m). The oxygen and carbon isotopic composition of planktonic (N. pachyderma sinistra and G. bulloides) and benthic (Cibicidoides wuellerstorfi, Epistominella exigua, and Melonis barleeanum) foraminifera have been analysed. Changes in sea surface temperatures (SST) are calculated using diatom and foraminiferal transfer functions. A new core top calibration for the Southern Ocean allows an extension of the method developed in the North Atlantic to estimate paleosalinities (Duplessy et al., 1991). The age scale is built using accelerator mass spectrometry (AMS) 14C dating of N. pachyderma s. for the last 35 kyr, and an astronomical age scale beyond. Changes in surface temperature and salinity clearly lead (by 3 to 7 kyr) deep water variations. Thus changes in deep water circulation are not the cause of the early response of the surface Southern Ocean to climatic changes. We suggest that the early warming and cooling of the Southern Ocean result from at least two processes acting in different orbital bands and latitudes: (1) seasonality modulated by obliquity affects the high-latitude ocean surface albedo (sea ice coverage) and heat transfer to and from the atmosphere; (2) low-latitude insolation modulated by precession influences directly the atmosphere dynamic and related precipitation/ evaporation changes, which may significantly change heat transfer to the high southern latitudes, through their control on latitudinal distribution of the major frontal zones and on the conditions of intermediate and deep water formation.

Supplement to: Labeyrie, Laurent D; Labracherie, Monique; Gorfti, N; Pichon, Jean-Jacques; Vautravers, Maryline J; Arnold, Maurice; Duplessy, Jean-Claude; Paterne, Martine; Michel, Elisabeth; Duprat, Josette M; Caralp, M; Turon, Jean-Louis (1996): Hydrographic changes of the Southern Ocean (southeast Indian sector) over the last 230 kyr. Paleoceanography, 11(1), 57-76

Identifier
DOI https://doi.org/10.1594/PANGAEA.734027
Related Identifier https://doi.org/10.1029/95PA02255
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.734027
Provenance
Creator Labeyrie, Laurent D; Labracherie, Monique; Gorfti, N; Pichon, Jean-Jacques; Vautravers, Maryline J (ORCID: 0000-0003-2534-219X); Arnold, Maurice; Duplessy, Jean-Claude; Paterne, Martine; Michel, Elisabeth ORCID logo; Duprat, Josette M; Caralp, M; Turon, Jean-Louis
Publisher PANGAEA
Publication Year 1996
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 3 datasets
Discipline Earth System Research
Spatial Coverage (96.461 LON, -46.022 LAT); South Pacific