Stable carbon and oxygen isotope ratios of foraminifera from Holocene sediments of the North Atlantic


Autoria(s): Millo, Christian; Sarnthein, Michael; Voelker, Antje HL; Erlenkeuser, Helmut
Cobertura

MEDIAN LATITUDE: 64.150747 * MEDIAN LONGITUDE: -32.362020 * SOUTH-BOUND LATITUDE: 61.526000 * WEST-BOUND LONGITUDE: -39.067500 * NORTH-BOUND LATITUDE: 67.930900 * EAST-BOUND LONGITUDE: -25.426500 * DATE/TIME START: 1995-08-18T00:00:00 * DATE/TIME END: 2002-07-06T00:44:00

Data(s)

22/09/2006

Resumo

The Denmark Strait Overflow (DSO) today compensates for the northward flowing Norwegian and Irminger branches of the North Atlantic Current that drive the Nordic heat pump. During the Last Glacial Maximum (LGM), ice sheets constricted the Denmark Strait aperture in addition to ice eustatic/isostatic effects which reduced its depth (today ~630 m) by ~130 m. These factors, combined with a reduced north-south density gradient of the water-masses, are expected to have restricted or even reversed the LGM DSO intensity. To better constrain these boundary conditions, we present a first reconstruction of the glacial DSO, using four new and four published epibenthic and planktic stable-isotope records from sites to the north and south of the Denmark Strait. The spatial and temporal distribution of epibenthic delta18O and delta13C maxima reveals a north-south density gradient at intermediate water depths from sigma0 ~28.7 to 28.4/28.1 and suggests that dense and highly ventilated water was convected in the Nordic Seas during the LGM. However, extremely high epibenthic delta13C values on top of the Mid-Atlantic Ridge document a further convection cell of Glacial North Atlantic Intermediate Water to the south of Iceland, which, however, was marked by much lower density (sigma0 ~28.1). The north-south gradient of water density possibly implied that the glacial DSO was directed to the south like today and fed Glacial North Atlantic Deep Water that has underthrusted the Glacial North Atlantic Intermediate Water in the Irminger Basin.

Formato

application/zip, 5 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.727694

doi:10.1594/PANGAEA.727694

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Millo, Christian; Sarnthein, Michael; Voelker, Antje HL; Erlenkeuser, Helmut (2006): Variability of the Denmark Strait Overflow during the Last Glacial Maximum. Boreas, 35(1), 50-60, doi:10.1111/j.1502-3885.2006.tb01112.x

Palavras-Chave #adjusted for vital effect; Age; AGE; Age, 14C AMS; Age, dated; Age, dated, error to older; Age, dated, error to younger; Age, dated standard deviation; Age dated; Age e -; Age e +; Age std dev; ARK-XVIII/1; C. lobatulus d13C; C. wuellerstorfi d13C; C. wuellerstorfi d18O; Cibicides lobatulus, d13C; Cibicidoides wuellerstorfi, d13C; Cibicidoides wuellerstorfi, d18O; corrected: delta 18O c. wuellerstorfi +0.64; corrected: delta 18O C. wuellerstorfi + 0.64; corrected: delta18O C.wuellerstorfi + 0.64 per mil; d18O; delta 18O, adjusted/corrected; Depth; Depth, composite; DEPTH, sediment/rock; Depth comp; Giant box corer; GIK23519-4; GIK23519-5; GKG; Gravity corer (Kiel type); Greenland Sea; Iceland Sea; Impact of Gateways on Ocean Circulation, Climate, and Evolution; Intercore correlation; Label; Mass spectrometer Finnigan MAT 251; N. pachyderma s d13C; N. pachyderma s d18O; Neogloboquadrina pachyderma sinistral, d13C; Neogloboquadrina pachyderma sinistral, d18O; OceanGateways; Ocean Gateways; Oceanpassagen; PC; Piston corer; Polarstern; POS210/2; Poseidon; PS62; PS62/003-2; PS62/004-3; PS62/015-3; Sample code/label; Size fraction: 150-250 µm; Size fraction: 250-400 µm; SL; uncorrected datas
Tipo

Dataset