Hernández-Almeida, Iván; Sierro, Francisco Javier; Cacho, Isabel; Flores, José-Abel (2018): (Supplement Fig. 2-4) Proxy data from IODP Site 306-U1314 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.891147, Supplement to: Hernández-Almeida, I et al. (2015): Subsurface North Atlantic warming as a trigger of rapid cooling events: evidence from the early Pleistocene (MIS 31–19). Climate of the Past, 11(4), 687-696, https://doi.org/10.5194/cp-11-687-2015
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Abstract:
Subsurface water column dynamics in the subpo-lar North Atlantic were reconstructed in order to improve theunderstanding of the cause of abrupt ice-rafted detritus (IRD)events during cold periods of the early Pleistocene. We usedpaired Mg/Ca andδ18O measurements ofNeogloboquad-rina pachyderma(sinistral - sin.), deep-dwelling planktonicforaminifera, to estimate the subsurface temperatures andseawaterδ18O from a sediment core from Gardar Drift, inthe subpolar North Atlantic. Carbon isotopes of benthic andplanktonic foraminifera from the same site provide informa-tion about the ventilation and water column nutrient gradient . Mg/Ca-based temperatures and seawaterδ18O suggestincreased subsurface temperatures and salinities during ice-rafting, likely due to northward subsurface transport of sub-tropical waters during periods of weaker Atlantic MeridionalOverturning Circulation (AMOC). Planktonic carbon iso-topes support this suggestion, showing coincident increasedsubsurface ventilation during deposition of IRD. Subsurfaceaccumulation of warm waters would have resulted in basalwarming and break-up of ice-shelves, leading to massive ice-berg discharges in the North Atlantic. The release of heatstored at the subsurface to the atmosphere would have helpedto restart the AMOC. This mechanism is in agreement withmodelling and proxy studies that observe a subsurface warm-ing in the North Atlantic in response to AMOC slowdownduring Marine Isotope Stage (MIS) 3.
Related to:
Elderfield, Henry; Ganssen, Gerald M (2000): Past temperature and d18O of surface ocean waters inferred from foraminiferal Mg/Ca ratios. Nature, 405(6785), 442-445, https://doi.org/10.1038/35013033
Meland, Marius Y; Jansen, Eystein; Elderfield, Henry (2005): Constraints on SST estimates for the northern North Atlantic/Nordic Seas during the LGM. Quaternary Science Reviews, 24(7-9), 835-852, https://doi.org/10.1016/j.quascirev.2004.05.011
Shackleton, Nicholas J (1974): Attainment of isotopic equilibrium between ocean water and the benthonic foraminifera genus Uvigerina: isotopic changes in the ocean during the last glacial. In: Labeyrie, L. (ed.) Les méthodes quantitatives d'etude des variation du climat au cours du Pléistocène. Colloques Internationaux du C.N.R.S (Centre Nationale de la Recherche Scientifique), 219, 203–209, hdl:10013/epic.41396.d001
Project(s):
Coverage:
Latitude: 56.364000 * Longitude: -27.888000
Date/Time Start: 2005-04-07T00:00:00 * Date/Time End: 2005-04-10T00:00:00
Minimum DEPTH, sediment/rock: 60.00 m * Maximum DEPTH, sediment/rock: 84.16 m
Event(s):
306-U1314 * Latitude: 56.364000 * Longitude: -27.888000 * Date/Time Start: 2005-04-07T00:00:00 * Date/Time End: 2005-04-10T00:00:00 * Elevation: -2800.0 m * Recovery: 765.63 m * Location: North Atlantic * Campaign: Exp306 (North Atlantic Climate 2) * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE)
Comment:
Including depths (meters composite depth) and ages (ka) tuned to LRO4.
Parameter(s):
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
4836 data points
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