Age models of sediment cores from the continental margin of northwest Africa
Cobertura |
MEDIAN LATITUDE: 23.203333 * MEDIAN LONGITUDE: -17.450000 * SOUTH-BOUND LATITUDE: 21.235000 * WEST-BOUND LONGITUDE: -18.055000 * NORTH-BOUND LATITUDE: 25.171667 * EAST-BOUND LONGITUDE: -16.845000 * DATE/TIME START: 1971-12-03T00:00:00 * DATE/TIME END: 1982-01-22T00:00:00 |
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Data(s) |
17/09/1991
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Resumo |
Diatom abundance and species composition were quantitatively studied in two latest Quaternary (~130 ka to the Present) sequences from the continental margin of northwest Africa. Off this region, coastal upwelling is well developed under the influence of the NE trade winds. Variations in diatom abundance in these cores are inferred to represent changes caused by varying degrees of the upwelling fertility. Times of high productivity are marked by high relative frequencies of Chaetoceros, while low productivity is marked by the dominance of Aulacoseira granulata. Upwelling increased during glacial episodes (isotopic stages 2-4 and 6) relative to isotopic stages 1 and 5. During the late Holocene, primary productivity levels are similar to those for Stage 5, but in the early Holocene upwelling intensities seem to have been weaker than today. The paleoproductivity reconstruction based on the diatom record is supported by paleoproductivity estimations based on the organic carbon content of the sediments (Sarnthein et al., 1987). |
Formato |
application/zip, 2 datasets |
Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.727569 doi:10.1594/PANGAEA.727569 |
Idioma(s) |
en |
Publicador |
PANGAEA |
Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
Fonte |
Supplement to: Abrantes, Fatima F (1991): Variability of upwelling off NW Africa during the latest Quaternary: diatom evidence. Paleoceanography, 6(4), 431-460, doi:10.1029/91PA00049 |
Palavras-Chave | #Age, comment; Age model; Age model in radiocarbon 14C ages; Atlantic Ocean; Calculated; Comm; Depth; DEPTH, sediment/rock; East Atlantic; GIK12392-1; GIK16030-1; Gravity corer (Kiel type); KAL; Kasten corer; M12392-1; M25; M60; Meteor (1964); Sedimentation rate; Sed rate; SL; SUBTROPEX 82 |
Tipo |
Dataset |