Geochemistry and sea-surface temperature reconstruction for sediment cores of the Iberian Margin

DOI

Biogenic records of the marine palaeoproductivity (carbonates, organic carbon, and C37 alkenones) and the molecular stratigraphy of past sea surface temperatures (SSTs; UK'37) were studied at high resolution in two cores of the Iberian Margin. The comparison of these records indicates that the oceanographic conditions switched abruptly during the past 160 kyr between three kinds of regimes. A first regime with high (17-22°C) SST and low productivity typifies the interglacial periods, marine isotopic stages (MIS) 5 and 1. Several periods during MIS 6, 2, and the terminations II and I are characterised by about 4-5°C colder SST and a higher organic matter accumulation, both of which define the second regime. This anticorrelation between SST and marine productivity suggests that these variations are related to the intensity of the coastal upwelling. By contrast with this upwelling behaviour, extremely low biological productivity and very cold SST (6-12°C) occurred during short phases of glacial MIS 6, 4, and 2, and as abrupt events (~1 kyr or less) during MIS 3. The three oceanographic regimes are consistent with micropalaeontological changes in the same cores based on foraminifera and diatoms.The general trend of these hydrologic changes follows the long-term glacial/interglacial cycle, but the millennium scale variability is clearly related to Heinrich events and Dansgaard-Oeschger cycles. Strengthening of the upwelling corresponds probably to an intensification of the subtropical atmospheric circulation over the North Atlantic which was influenced by the presence of continental ice sheets. However, extreme glacial conditions due to massive discharges of icebergs interrupted the upwelling. Interestingly, both terminations II and I coincided with strong but transient intensification of the upwelling.

Supplement to: Pailler, Delphine; Bard, Edouard (2002): High frequency palaeoceanographic changes during the past 140000 yr recorded by the organic matter in sediments of the Iberian Margin. Palaeogeography, Palaeoclimatology, Palaeoecology, 181(4), 431-452

Identifier
DOI https://doi.org/10.1594/PANGAEA.736599
Related Identifier https://doi.org/10.1016/S0031-0182(01)00444-8
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.736599
Provenance
Creator Pailler, Delphine; Bard, Edouard ORCID logo
Publisher PANGAEA
Publication Year 2002
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (-10.166W, 37.800S, -9.861E, 40.582N); Porto Seamount; Marge Ibérique
Temporal Coverage Begin 1995-07-07T00:00:00Z
Temporal Coverage End 1995-07-09T00:00:00Z