Geochemistry of sediments of stage 5 of the Nordic seas


Autoria(s): Fronval, Torben; Jansen, Eystein; Haflidason, Haflidi; Sejrup, Hans Petter
Cobertura

MEDIAN LATITUDE: 68.108683 * MEDIAN LONGITUDE: -6.803537 * SOUTH-BOUND LATITUDE: 66.678300 * WEST-BOUND LONGITUDE: -13.870667 * NORTH-BOUND LATITUDE: 69.483333 * EAST-BOUND LONGITUDE: 4.576700 * DATE/TIME START: 1971-01-01T00:00:00 * DATE/TIME END: 1985-08-09T10:15:00

Data(s)

22/07/1998

Resumo

Stable isotope, foraminifera and ice rafted detritus (IRD) records covering the last interglacial (the Eemian) from 7 sediment cores in a transect from the Norwegian to the Greenland Sea are presented. The percentages of Neogloboquadrina pachyderma (s.) and Globigerina quinqueloba, foraminiferal content, and to some extent planktonic stable isotope records, demonstrate marked, regional changes in surface water conditions. Importantly, the variability in the abundances of subpolar foraminifera and foraminiferal content are not coherent, implying that these two types of proxies fluctuated independently of each other and most likely reflect changes in sea surface temperature and surface water carbonate productivity, respectively. Paleoceanographic reconstructions demonstrate significant movements of the oceanographic fronts. At the warmest periods, the Arctic front was located far west of the present-day location, at least within the Iceland Sea region. At 126-125 ka, this was most probably due to a stronger or more westerly located Norwegian current. Within the later warm intervals, higher heat flux to the western part of the basin reflects a combination of a stronger Irminger current and/or a weaker east Greenland current. During the main cold spell at ~124 ka, a diffuse Arctic front had a more southeasterly location than today, and intrusion of Atlantic surface waters was probably limited to a narrow corridor in the Eastern Norwegian Sea. A general correspondence between minima in sea surface temperatures and light benthic delta18O may indicate enhanced influx of freshwater to the basin within the cold events. At least in the Norwegian Sea, we find some evidence that the changes in surface water conditions are associated with changes in deep water ventilation. The majority of the fluctuations may be related to occasional breakdown or reduction of the thermohaline circulation within the Nordic seas. In the earliest Eemian, this could result from meltwater forcing. During the remaining part of the last interglacial the fine balance between temperature and salinity, which the deep water formation is depending on, may have been disturbed by periodic increases in fresh water supply or variable influx of warm Atlantic surface waters.

Formato

application/zip, 3 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.743287

doi:10.1594/PANGAEA.743287

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Fronval, Torben; Jansen, Eystein; Haflidason, Haflidi; Sejrup, Hans Petter (1998): Variability in surface and deep water conditions in the nordic seas during the last interglacial period. Quaternary Science Reviews, 17(9-10), 963-985, doi:10.1016/S0277-3791(98)00038-9

Palavras-Chave #104-644A; 57-07; 71-19; Al2O3; Aluminium oxide; BC; Box corer; Calcium oxide; CaO; Comment; Depth; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Event; FeO; GC; Gravity corer; Gravity corer (Kiel type); Håkon Mosby; HM57; HM57-07; HM71; HM71-19/1; HM71-25; HM79; HM79-31; Iron oxide, FeO; Joides Resolution; K2O; Label; Leg104; Magnesium oxide; Manganese oxide; MgO; MnO; Na2O; Norwegian Sea; Ocean Drilling Program; ODP; ODP sample designation; P2O5; Phosphorus oxide; population; Potassium oxide; Sample code/label; Silicon dioxide; SiO2; SL; Sodium oxide; Sum; TiO2; Titanium oxide
Tipo

Dataset