HR: 0800h
AN: PP31B-0413    [Abstracts]
TI: Temperature and Productivity Calibration off Southwest and South Portugal: Planktonic Foraminifera Trace Element Proxies Application
AU: * Salgueiro, E
EM: esalgueiro@uchicago.edu
AF: Department of the Geophysical Sciences, The University of Chicago, 5734 S. Ellis Avenue, Chicago, IL 60637, United States
AU: * Salgueiro, E
EM: esalgueiro@uchicago.edu
AF: Dept. Geologia Marinha, Instituto Nacional de Engenharia, Tecnologia e Inovaà§àŁo I.P., Estrada da Portela, Apartado 7586, Alfragide, 2721- 866, Portugal
AU: Martin, P A
EM: pmartin@uchicago.edu
AF: Department of the Geophysical Sciences, The University of Chicago, 5734 S. Ellis Avenue, Chicago, IL 60637, United States
AU: Abrantes, F
EM: fatima.abrantes@ineti.pt
AF: Dept. Geologia Marinha, Instituto Nacional de Engenharia, Tecnologia e Inovaà§àŁo I.P., Estrada da Portela, Apartado 7586, Alfragide, 2721- 866, Portugal
AB: Planktonic foraminiferal trace element ratios (Mg/Ca, Ba/Ca, Cd/Ca) from core-top sediment samples collected along the southwestern and southern Portuguese margin (35.5 - 38.5°N, 7 - 11°W) were determined to assess the latitudinal and longitudinal changes in surface water conditions relatively to the present hydrographic conditions and to calibrate sea surface temperature (SST) and nutrient proxy for this seasonal upwelling region. Three species with different depth habitats, linked to specific hydrographic conditions, were used for this study area. Globigerina bulloides an upper water column species, reflects the modern summer coastal upwelling with cold waters and high primary productivity close to the coast along the southwestern margin. Globigerinoides ruber (white) a surface dwelling species, and Globorotalia inflata a deep dwelling species, which are associated with the Portugal Coastal Countercurrent a winter-time warm current. Both these species show their dominance on the southern margin, where upwelling only occurs occasionally, and offshore of the southwestern coast, outside of the direct influence of coastal upwelling (well stratified surface waters). Preliminary SST results, derived from G. bulloides and G. ruber (white) Mg/Ca, indicate 17°C close to the southwestern margin, that is 3-4°C colder temperatures than found offshore and off the southern margin. This pattern reflects the summer upwelled waters and is in excellent agreement with the modern satellite SST average values. G. inflata reflects similar and colder temperatures of calcification and higher values of the nutrient trace element proxies (Ba/Ca and Cd/Ca) than the other study species at both margins indicating the presence of colder and nutrient-richer sub-superficial waters. The insights gained from this study will be applied to estimate past climate conditions in this particular region and in other upwelling areas.
DE: 4924 Geochemical tracers
DE: 4944 Micropaleontology (0459, 3030)
DE: 4964 Upwelling (4279)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting