(Figure 2) Proxy records of sediment core GeoB6007-2


Autoria(s): Bamberg, Audrey; Rosenthal, Yair; Paul, André; Heslop, David; Mulitza, Stefan; Rühlemann, Carsten; Schulz, Michael
Cobertura

LATITUDE: 30.850000 * LONGITUDE: -10.268300 * DATE/TIME START: 1999-10-18T15:50:00 * DATE/TIME END: 1999-10-18T15:50:00

Data(s)

06/10/2010

Resumo

Central waters of the North Atlantic are fundamental for ventilation of the upper ocean and are also linked to the strength of the Atlantic Meridional Overturning Circulation (AMOC). Here, we show based on benthic foraminiferal Mg/Ca ratios, that during times of enhanced melting from the Laurentide Ice Sheet (LIS) between 9.0-8.5 thousand years before present (ka) the production of central waters weakened the upper AMOC resulting in a cooling over the Northern Hemisphere. Centered at 8.54 ± 0.2 ka and 8.24 ± 0.1 ka our dataset records two ~150-year cooling events in response to the drainage of Lake Agassiz/Ojibway, indicating early slow-down of the upper AMOC in response to the initial freshwater flux into the subpolar gyre (SPG) followed by a more severe weakening of both the upper and lower branches of the AMOC at 8.2 ka. These results highlight the sensitivity of regional North Atlantic climate change to the strength of central-water overturning and exemplify the impact of both gradual and abrupt freshwater fluxes on eastern SPG surface water convection. In light of the possible future increase in Greenland Ice Sheet melting due to global warming these findings may help us to better constrain and possibly predict future North Atlantic climate change.

Formato

application/zip, 2 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.745950

doi:10.1594/PANGAEA.745950

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Bamberg, Audrey; Rosenthal, Yair; Paul, André; Heslop, David; Mulitza, Stefan; Rühlemann, Carsten; Schulz, Michael (2010): Reduced North Atlantic Central Water formation in response to early Holocene ice-sheet melting. Geophysical Research Letters, 37, L17705, doi:10.1029/2010GL043878

Palavras-Chave #Age; AGE; BGR; Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover; Calculated from Mg/Ca ratios; Calculated from Mg/Ca ratios and d18O corrected; Center for Marine Environmental Sciences; corrected for global ice volume changes; Depth; DEPTH, sediment/rock; GeoB6007-2; Gravity corer (Kiel type); H. balthica d13C; H. balthica d18O; Hyalinea balthica, d13C; Hyalinea balthica, d18O; Integrierte Analyse zwischeneiszeitlicher Klimadynamik; INTERDYNAMIK; Intermediate Water Temperatures (IMWT); M45/5a; Magnesium/Calcium ratio; MARUM; Mass spectrometer Finnigan MAT 251; Measured from H. balthica with ICPMS in solution (Rosenthal et al. 1999); Meteor (1986); Mg/Ca; seawater; SL; Temp; Temperature, water
Tipo

Dataset