Content uploaded by Samuel Toucanne
Author content
All content in this area was uploaded by Samuel Toucanne on Oct 02, 2022
Content may be subject to copyright.
Chapter 6
The BøllingAllerød Interstadial
Filipa Naughton
1,2
, Marı´a F. Sa´nchez-Gon
˜i
3,4
, Amaelle Landais
5
, Teresa Rodrigues
1,2
,
Natalia Vazquez Riveiros
6
and Samuel Toucanne
6
1
Portuguese Institute for Sea and Atmosphere (IPMA), Lisboa, Portugal,
2
Center of Marine Sciences (CCMAR), Algarve University, Campus de
Gambelas, Faro, Portugal,
3
Environnements, Pale
´oenvironnements Oce
´aniques et Continentaux, Ecole Pratique des Hautes Etudes (EPHE, PSL),
Pessac, France,
4
University of Bordeaux, EPOC, Campus de Gambelas, Faro, France,
5
UMR8212, CEACNRSUVSQUPS, Laboratoire des
Sciences du Climat et de l’Environnement (IPSL), Gif-sur-Yvette, France,
6
Institut Franc¸ ais de Recherche pour l’Exploitation de la Mer (IFREMER),
Unite
´de Recherche Ge
´osciences Marines, Plouzane
´, France
Chapter outline
6.1 Definition, timing and causes of the BøllingAllerød
episode 45
6.2 The impact of B-A in the eastern North Atlantic and
Europe 47
References 48
6.1 Definition, timing and causes of the BøllingAllerød episode
The BøllingAllerød (B-A) interstadial, the first warm event of the last deglaciation in the northern hemisphere, was
originally described as consisting of three phases or chronozones (Mangerud et al., 1974): the Bølling and Allerød
warm interstadials and the Older Dryas cold stadial in-between. These phases were firstly identified in two Danish sites
based on plant remains: the Bølling and the Allerød sites (Hartz and Milthers, 1901; Iversen, 1942, 1954). The Older
Dryas was characterised by the presence of subarctic/arctic flora (e.g. Dryas octopetala) and the Allerød and Bølling
interstadials by the expansion of tree birch. Some high-resolution records from Europe further indicate that the B-A
was interrupted not only by the Older Dryas but also by the intra-Allerød cold event (e.g. Von Grafenstein et al., 1999;
Brauer et al., 2000;Hoek, 2009). We know now that vegetation changes associated with the B-A interstadial did not
occur synchronously outside this region and that the term B-A should not be generalised (e.g. Hoek, 2009). However,
as the B-A interstadial has been extensively used in records around the world and is now so firmly fixed in the litera-
ture, replacing it would be a big challenge (Hoek, 2009; Rasmussen et al., 2014). Therefore the INTIMATE event stra-
tigraphy recommends that the B-A can be used as a synonym for DansgaardOeschger 1 or Interstadial 1, but not as a
synonym for Greenland Interstadial 1 (GI-1) (Rasmussen et al., 2014). Also, because the B-A is subdivided into five
subevents in European records whilst the GI-1 is subdivided into seven subevents in Greenland ice, the INTIMATE
event stratigraphy group recommends to avoid giving names to these centennial-scale events because of the risk of mis-
interpretation (e.g. Rasmussen et al., 2014). Detecting these centennial-scale events is very challenging in some marine
and terrestrial sedimentary sequences due to their relative low temporal resolution and because some proxies are not
sensitive enough to respond to these abrupt cold spells.
We consider here that the B-A is the first northern hemisphere abrupt warming event of the last deglaciation that
occurred during an increase of boreal summer insolation, and precisely between Heinrich Stadial 1/Oldest Dryas and
the Younger Dryas (e.g. Severinghaus and Brook, 1999;Hoek, 2009;Denton et al., 2010;Naughton et al., 2016); that
is, 14.612.9 ka b2k (b2k: before CE 2000) or 14.712.85 years BP (BP: before present CE 1950) (Rasmussen et al.,
2014). In Antarctica, the B-A is synchronous with a cooling event; the Antarctic Cold Reversal (Stenni et al., 2001,
Pedro et al., 2016).
One of causes of the B-A abrupt warming episode in the northern hemisphere involves the ‘bipolar seesaw’ mecha-
nism, or the ‘heat piracy’ theory, associated with the meridional heat transport of the Atlantic Meridional Overturning
45
European Glacial Landscapes. DOI: https://doi.org/10.1016/B978-0-323-91899-2.00015-2
©2023 Elsevier Inc. All rights reserved.
(Continued)
46 PART | II Climate changes during the Last Deglaciation in the Eastern North Atlantic region
Circulation (AMOC) (e.g. Crowley, 1992;Broecker, 1998;Rahmstorf, 2002). During the preceding Heinrich Stadial 1
(HS 1), the massive discharges and melting of northern hemisphere ice sheets triggered the weakening of the AMOC
and the reduced northward heat transport, explaining the opposing behaviour between the two hemispheres (e.g.
Crowley, 1992;Broecker, 1998). The contrasting signal in both hemispheres, during the B-A, with warm in the north
and cooling in the south would be explained by a more vigorous AMOC, facilitating the northward ocean heat transport
(e.g. Crowley, 1992;Broecker, 1998;Rahmstorf, 2002). Some authors suggest that the interruption of meltwater dis-
charges into the North Atlantic have favoured the resumption of the AMOC and the consequent warming of the north-
ern Hemisphere causing the HS 1/B-A transition (e.g. Liu et al., 2009;Lohmann et al., 2016;Ng et al., 2018). Some
authors (Gregoire et al., 2016, Ng et al., 2018) suggest that this warming could have triggered Laurentide ice sheet
melting and the collapse of the Greenland and Iceland ice sheets at around 14.5 ka and a subsequent 1422 m sea-level
rise (Lambeck et al., 2014; Gregoire et al., 2016; Telesinski et al., 2014; Norðdahl and Ingo
´lfsson, 2015). This meltwa-
ter pulse would reduce rather than invigorate the AMOC after 14.5 ka; but this was not detected in marine records (Ng
et al., 2018). Other authors, based on several transient simulations of the last deglaciation, show that the increase of
CO
2
had a pivotal role and contributed to an abrupt increase in the AMOC despite meltwater input into the North
Atlantic (Liu et al., 2009; Shakun et al., 2012; Zhang et al., 2017; Obase and Abe-Ouchi, 2019). Some authors further
suggest that the AMOC resumption during the B-A was triggered by a warming at intermediate depths of the North
Atlantic during the preceding HS 1 as a result of the seesaw effect (Thiagarajan et al., 2014; Su et al., 2016).
Regardless of the role of each driver, data and climate simulations agree with a more vigorous state of the AMOC
and warming in the northern hemisphere during the B-A (e.g. McManus et al., 2004;Liu et al., 2009;Ng et al., 2018).
Climate simulations further suggest an increase of moisture in Europe as a response to the AMOC strengthening (e.g.
Rahmstorf, 2006).
6.2 The impact of B-A in the eastern North Atlantic and Europe
Sea surface temperature (SST) estimates from alkenones and planktic foraminifera assemblages reveal that the B-A was
marked by an abrupt SST increase of 410 %
oC in the eastern North Atlantic mid-latitudes (western Iberian Margin and
W Mediterranean Sea) (Fig. 6.1) (e.g. Bard et al., 2000;Cacho et al., 2001;Pailler and Bard, 2002;Martrat et al., 2007;
2014;Rodrigues et al., 2010;Salgueiro et al., 2014;Naughton et al., 2016). An abrupt warming was also detected in
several records from the Bay of Biscay by the decrease of the polar planktic foraminifera Neogloboquadrina pachyder-
ma abundances (Fig. 6.1) (e.g. Zaragosi et al., 2001). An increase of 4C in SST based on Mg/Ca ratios of planktic fora-
minifera was also recorded in the central and western North Atlantic mid-latitudes (Carlson et al., 2008; Repschla
¨ger
et al., 2015). The reduction of meltwater fluxes from Eurasian Ice sheets is testified by a decrease in the Channel River
runoff (Fig. 6.1)(Zaragosi et al., 2001; Me
´not et al., 2006). At this time, the AMOC became strongly vigorous, as sup-
ported by the
231
Pa/
230
Th records from the western North Atlantic mid-latitudes and the compiled North Atlantic dataset
(McManus et al., 2004; Ng et al., 2018). In Greenland, air temperatures increased by about 810C(Fig. 6.1)(Buizert
et al., 2014). The increase of atmospheric summer temperature of B35C is also detected in northern and southern
Europe (Renssen and Isarin, 2001; Dormoy et al., 2009), and supported by the oxygen-isotope ratios of deep-dwelling
ostracods from Lake Ammersee (southern Germany) (Von Grafenstein et al., 1999). The B-A warming led the expan-
sion of forest in the Iberian Peninsula (Fig. 6.1), southern France and central Europe, as shown by pollen records (e.g.
Litt and Stebich, 1999;Hoek, 2009;Fletcher et al., 2010;Naughton et al., 2016 and references therein) and by the δ
13
C
decrease in speleothem records (Genty et al., 2006; Moreno et al., 2010). However, pollen and speleothems records
indicate that the southern and central European temperate forests expanded progressively and the δ
13
C decreased gradu-
ally from the Bølling to the Allerød, contrasting with the Greenland temperature pattern that shows the warmest peak at
L
FIGURE 6.1 (A) Iberian margin alkenone-derived Sea surface temperature (SST) records (U
k
37 SST) (Bard et al., 2000; Pailler and Bard, 2002;
Martrat et al., 2007); (B) Iberian margin planktic foraminifera-derived SST records (Salgueiro et al., 2014; Naughton et al., 2016); (C) abundance of
planktic polar foraminifera Neogloboquadrina pachyderma from western Iberia and French margins (Salgueiro et al., 2014; Zaragosi et al., 2001); (D)
meltwater discharges (C37:4) from western Iberian and French margins (Bard et al., 2000; Me
´not et al., 2006; Martrat et al., 2007); (E) isoprenoid tet-
raether (BIT) index from western French margin (Me
´not et al., 2006); (F) ice-rafted debris (IRD) in the western Iberian margin (Bard et al., 2000;
Naughton et al., 2016) and (G) in the western French margin (Me
´not et al., 2006); (H) temperate forest (TF), (I) heathland and (J) semidesert plants
(SD) abundances in NW Iberian margin record MD032697 (Naughton et al., 2016); (K) channel river flood (number of flood events per 250 years)
(Toucanne et al., 2015); (L) ex231Pa0/ex230Th0 from composite North Atlantic records (blue line) (black bold line: smoothed record) (Ng et al.,
2018) and from the western North Atlantic (light blue) (OCE326-GGC5; McManus et al., 2004); (M) Greenland temperature (Buizert et al., 2014);
(N) Atmospheric CO
2
reconstructed from West Antarctic Ice Sheet Divide ice core (Marcott et al., 2014). Heinrich Stadial 1 (HS 1), pre-HS 1 and
Younger Dryas: light blue bands.
The BøllingAllerød Interstadial Chapter | 6 47
the onset of GI 1 (Fig. 6.1). The temperature increase is clearly evident in most of the North Atlantic, European and
Greenland records, and agrees with a more vigorous AMOC at the onset of the Bølling (Fig. 6.1). Therefore, the con-
trasting pattern observed in central and southern European pollen and speleothem records with that of Greenland could
be the result of changes in moisture availability rather than in temperature (e.g. Naughton et al., 2016). The continuous
increase of moisture availability from the Bølling to the Allerød was also detected in other regions, such as in the west-
ern and central Mediterranean region (e.g. Dormoy et al., 2009;Desprat et al., 2013). Since the AMOC was vigorous at
the onset of the Bølling, it should be expected that moisture delivery was highest at the beginning of this interval in
Europe. However, changes in moisture delivery result from complex interactions between ocean moisture sources and
modifications in atmospheric dynamics (e.g. Naughton et al., 2009; 2019). The relative deficit in precipitation at the
onset of the Bølling, under a more vigorous AMOC mode, can be explained by changes in the position and shape of the
jet stream, which is responsible for the delivery of moisture over Europe via the westerly winds. The jet stream was
probably displaced further north in response to the North Atlantic high latitude warming with a more meandric form at
the onset of the Bølling. This would favour the transfer of high amounts of moisture to the North Atlantic high latitudes
lowering the precipitation in central and southern Europe (Naughton et al., 2016). This hypothesis has been proposed
for previous D-O warmings and is supported by δD and deuterium excess data from Greenland ice cores (Masson-
Delmotte et al., 2005; Gon
˜i et al., 2009), even if the climatic boundary conditions are not the same during the Marine
Isotope Stage 3 (B6026 ka) and the last deglaciation.
References
Bard, E., Rostek, F., Turon, J.L., Gendreau, S., 2000. Hydrological impact of Heinrich events in the subtropical northeast Atlantic. Science 289,
13211324.
Brauer, A., Gu
¨nter, C., Johnsen, S.J., Negendank, J.F.W., 2000. Land-ice teleconnections of cold climatic periods during the last Glacial/Interglacial
transition. Climate Dynamics 16, 229239.
Broecker, W.S., 1998. Paleocean circulation during the last deglaciation: a bipolar seesaw? Paleoceanography 13, 119121.
Buizert, C., Gkinis, V., Severinghaus, J.P., He, F., Lecavalier, B.S., Kindler, P., et al., 2014. Greenland temperature response to climate forcing during
the last deglaciation. Science 345 (6201), 11771180.
Cacho, I., Grimalt, J.O., Canals, M., Sbaffi, L., Shackleton, N.J., Schonfeld, J., et al., 2001. Variability of the western Mediterranean Sea surface tem-
perature during the last 25,000 years and its connection with the Northern Hemisphere climatic changes. Paleoceanography 16, 4052.
Carlson, A.E., Oppo, D.W., Came, R.E., LeGrande, A.N., Keigwin, L.D., Curry, W.B., 2008. Subtropical Atlantic salinity variability and Atlantic
meridional circulation during the last deglaciation. Geology 36, 991994.
Crowley, T.J., 1992. North Atlantic deep water cools the Southern Hemisphere. Paleoceanography 7, 489497.
Denton, G.H., Anderson, R.F., Toggweiler, J.R., Edwards, R.L., Schaefer, J.M., Putnam, A.E., 2010. The last glacial termination. Science 328,
16521656.
Desprat, S., Combourieu-Nebout, N., Essallami, L., Sicre, M.A., Dormoy, I., Peyron, O., et al., 2013. Deglacial and Holocene vegetation and climatic
changes in the southern Central Mediterranean from a direct land-sea correlation. Climate of the Past 9, 767787.
Dormoy, I., Peyron, O., Combourieu Nebout, N., Goring, S., Kotthoff, U., Magny, M., et al., 2009. Terrestrial climate variability and seasonality
changes in the Mediterranean region between 15,000 and 4000 years BP deduced from marine pollen records. Climate of the Past 5, 615632.
Fletcher, W.J., Sanchez Gon
˜i, M.F., Peyron, O., Dormoy, I., 2010. Abrupt climate changes of the last deglaciation detected in a western
Mediterranean forest record. Climate of the Past 6, 245264.
Genty, D., Blamart, D., Ghaleb, B., Plagnes, V., Causse, C., Bakalowicz, M., et al., 2006. Timing and dynamics of the last deglaciation from
European and North African d13C stalagmite profiles—comparison with Chinese and South Hemisphere stalagmites. Quaternary Science Reviews
25, 21182142.
Gon
˜i, M.F.S., Landais, A., Cacho, I., Duprat, J., Rossignol, L., 2009. Contrasting intrainterstadial climatic evolution between high and middle North
Atlantic latitudes: a close-up of Greenland Interstadials 8 and 12. Geochemistry, Geophysics, Geosystems 10 (4).
Gregoire, L.J., Otto-Bliesner, B., Valdes, P.J., Ruza Ivanovic, R., 2016. Abrupt Bølling warming and ice saddle collapse contributions to the
Meltwater Pulse 1a rapid sea level rise. Geophysical Research Letters 43 (17), 91309137. Available from: https://doi.org/10.1002/
2016GL070356. 2016 Sep 16.
Hartz, N., Milthers, V., 1901. Det senglaciale Ler i Allero
¨d Teglvaerksgrav. Meddelelser Danmarks Geologisk Forening 8, 3159.
Hoek, Z.W., 2009. “Bølling-Allerød Interstadial”. Encyclopedia of Paleoclimatology and Ancient Environments. Encyclopedia of Earth Sciences
Series. Encyclopedia of Earth Sciences Series. Springer, pp. 100103. Available from: http://doi.org/10.1007/978-1-4020-4411-3_26, ISBN 978-
1-40204551-6.
Iversen, J., 1942. En pollenanalytisk Tidsfaestelse af Ferskvandslagene ved Norre Lingby. Meddelelser Danmarks Geologisk Forening 10, 130151.
Iversen, J., 1954. The Late-Glacial flora of Denmark and its relation to climate and soil. Danmarks Geologiske Undersøgelser. Række 80, 87119.
Lambeck, K., Rouby, H., Purcell, A., Sun, Y., Sambridge, M., 2014. Sea level and global ice volumes from the Last Glacial Maximum to the
Holocene. Proceedings of National Academy Sciences USA 111, 1529615303. Available from: https://doi.org/10.1073/pnas.1411762111.
Litt, T., Stebich, M., 1999. Bio- and chronostratigraphy of the Lateglacial in the Eifel region, Germany. Quaternary International 61, 516.
48 PART | II Climate changes during the Last Deglaciation in the Eastern North Atlantic region
Liu, Z., Otto-Bliesner, B., He, F., Brady, E., Thomas, R., Clark, P.U., et al., 2009. Transient climate simulation of last deglaciation with a new mecha-
nism for Bølling-Allerød warming. Science 325, 310314.
Lohmann, G., Zhang, X., Knorr, G., 2016. Abrupt climate change experiments: the role of freshwater, ice sheets and deglacial warming for the
Atlantic Meridional Overturning Circulation. Polarforschung 85, 161170. Available from: https://doi.org/10.2312/polfor.2016.013.
Mangerud, J., Andersen, S.T., Berglund, B.E., Donner, J.J., 1974. Quaternary stratigraphy of Norden, a proposal for terminology and classification.
Boreas 3, 109126.
Marcott, S.A., Bauska, T.K., Buizert, C., Steig, E.J., Rosen, J.L., Cuffey, K.M., et al., 2014. Centennial-scale changes in the global carbon cycle dur-
ing the last deglaciation. Nature 514, 616619.
Martrat, B., Grimalt, J.O., Shackleton, N.J., de Abreu, L., Hutterli, M.A., Stocker, T.F., 2007. Four climate cycles of recurring deep and surface water
destabilizations on the Iberian Margin. Science 317, 502507.
Martrat, B., Jimenez-Amat, P., Zahn, R., Grimalt, J.O., 2014. Similarities and dissimilarities between the last two deglaciations and interglaciations in
the North Atlantic region. Quaternary Science Reviews 99, 122134.
Masson-Delmotte, V., Jouzel, J., Landais, A., Stievenard, M., Johnsen, S.J., White, J.W.C., et al., 2005. GRIP deuterium excess reveals rapid and
orbital-scale changes in Greenland moisture origin. Science 309 (5731), 118121.
McManus, J.F., Francois, R., Gherardi, J.-M., Keigwin, L.D., Brown-Leger, S., 2004. Collapse and rapid resumption of Atlantic meridional circulation
linked to deglacial climate changes. Nature 428, 834837.
Me
´not, G., Bard, E., Rostek, F., Weijers, J.W., Hopmans, E.C., Schouten, S., et al., 2006. Early reactivation of European rivers during the last deglaci-
ation. Science 313 (5793), 16231625.
Moreno, A., Stoll, H.M., Jimenez-Sanchez, M., Cacho, I., Valero-Garces, B., Ito, E., et al., 2010. A speleothem record of rapid climatic shifts during
last glacial period from Northern Iberian Peninsula. Global and Planetary Change 71, 218231. Available from: https://doi.org/10.1016/j.
gloplacha.2009.10.002.
Naughton, F., Costas, S., Gomes, S.D., Rodrigues, T., Desprat, S., Bronk-Ramsey, C., et al., 2019. Coupled ocean and atmospheric changes during the
Younger Dryas in southwestern Europe. Quaternary Science Reviews 212, 108120. Available from: https://doi.org/10.1016/j.
quascirev.2019.03.033.
Naughton, F., Gon
˜i, M.S., Kageyama, M., Bard, E., Duprat, J., Cortijo, E., et al., 2009. Wet to dry climatic trend in north-western Iberia within
Heinrich events. Earth and Planetary Science Letters 284 (34), 329342.
Naughton, F., Gon
˜ic, M.F.S., Rodrigues, T., Salgueiro, E., Costas, S., Desprat, S., et al., 2016. Climate variability across the last deglaciation in NW
Iberia and its margin. Quaternary International 414, 922. Available from: https://doi.org/10.1016/j.quaint.2015.08.073.
Ng, H.C., Robinson, L.F., McManus, J.F., Mohamed, K.J., Jacobel, A.W., Ivanovic, R.F., et al., 2018. Coherent deglacial changes in western Atlantic
Ocean circulation. Nature Communication 9 (1). Available from: https://doi.org/10.1038/s41467-018-05312.
Norðdahl, H., Ingo
´lfsson, O., 2015. Collapse of the Icelandic ice sheet controlled by sea-level rise? Arktos 1, 113.
Obase, T., Abe-Ouchi, A., 2019. Abrupt Bølling-Allerød warming simulated under gradual forcing of the last deglaciation. Geophysical Research
Letters 46 (20), 1139711405.
Pailler, D., Bard, E., 2002. High frequency palaeoceanographic changes during the past 140 000 yr recorded by the organic matter in sediments of the
Iberian Margin. Palaeogeography, Palaeoclimatology, Palaeoecology 181, 431452.
Pedro, J.B., Bostock, H.C., Bitz, C.M., He, F., Vandergoes, M.J., Steig, E.J., et al., 2016. The spatial extent and dynamics of the Antarctic Cold
Reversal. Nature Geoscience 9 (1), 5155.
Rahmstorf, S., 2002. Ocean circulation and climate during the past 120,000 years. Nature 419, 207214.
Rahmstorf, S., 2006. Thermohaline Ocean circulation. In: Elias, S.A. (Ed.), Encyclopedia of Quaternary Sciences. Elsevier, Amsterdam.
Rasmussen, S.O., Bigler, M., Blockley, S.P., Blunier, T., Buchardt, S.L., Clausen, H.B., et al., 2014. A stratigraphic framework for abrupt climatic
changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stra-
tigraphy. Quaternary Science Reviews 106, 1428.
Renssen, H., Isarin, R.F.B., 2001. The two major warming phases of the last deglaciation at similar to 14.7 and similar to 11.5 ka cal BP in Europe:
climate reconstructions and AGCM experiments. Global and Planetary Change 30, 117153.
Repschla
¨ger, J., Weinelt, M., Kinkel, H., Andersen, N., Garbe-Schhonberg, D., Schwab, C., 2015. Response of the subtropical North Atlantic surface
hydrography on deglacial and Holocene AMOC changes. Paleoceanography 30, 456476. Available from: https://doi.org/10.1002/
2014PA002637.
Rodrigues, T., Grimalt, J.O., Abrantes, F., Naughton, F., Jose-Abel Flores, J.-A., 2010. The last glacial-interglacial transition (LGIT) in the eastern mid-
latitudes of the North Atlantic: abrupt sea surface temperature change and sea level implications. Quaternary Science Reviews 29, 18531862.
Salgueiro, E., Naughton, F., Voelker, A.H.L., de Abreu, L., Alberto, A., Rossignol, L., et al., 2014. Past circulation along the western Iberian margin:
a time slice vision from the Last Glacial to the Holocene. Quaternary Science Reviews 106, 316329.
Severinghaus, J.P., Brook, E.J., 1999. Abrupt climate change at the end of the last glacial period inferred from trapped air in polar Ice. Science 286,
930934. Available from: https://doi.org/10.1126/science.286.5441.930.
Shakun, J., Clark, P., He, F., Marcott, S.A., Mix, A.C., Liu, Z., et al., 2012. Global warming preceded by increasing carbon dioxide concentrations
during the last deglaciation. Nature 484 (4954), 2012. Available from: https://doi.org/10.1038/nature10915.
Stenni, B., Masson-Delmotte, V., Johnsen, S.J., Jouzel, J., Longinelli, A., Monnin, E., et al., 2001. An oceanic cold reversal during the last deglacia-
tion. Science 293, 20742077.
Su, Z., Ingersoll, A.P., He, F., 2016. On the Abruptness of BøllingAllerød Warming. Journal of Climate 29, 49654975.
The BøllingAllerød Interstadial Chapter | 6 49
Telesinski, M.M., Spielhagen, R.F., Bauch, H.A., 2014. Water mass evolution of the Greenland Sea since late glacial times. Climate of the Past 10,
123136.
Thiagarajan, N., Subhas, A.V., Southon, J.R., Eiler, J.M., Adkins, J.F., 2014. Abrupt pre-BøllingAllerød warming and circulation changes in the
deep ocean. Nature 511, 7578. Available from: https://doi.org/10.1038/nature13472.
Toucanne, S., Soulet, G., Freslon, N., Jacinto, R.S., Dennielou, B., Zaragosi, S., et al., 2015. Millennial-scale fluctuations of the European Ice Sheet at
the end of the last glacial, and their potential impact on global climate. Quaternary Science Reviews 123, 113133.
Von Grafenstein, U., Erlenkeuser, H., Brauer, A., Jouzel, J., Johnsen, S.J., 1999. A mid-European decadal isotope-climate record from 15,500 to 5000
years B.P. Science 284, 16541657.
Zaragosi, S., Eynaud, F., Pujol, C., Auffret, G.A., Turon, J.L., Garlan, T., 2001. Initiation of the European deglaciation as recorded in the northwestern
Bay of Biscay slope environments (Meriadzek Terrace and Trevelyan Escarpment): a multi-proxy approach. Earth and Planetary Science Letters
188 (34), 493507.
Zhang, X., Knorr, G., Lohmann, G., Barker, S., 2017. Abrupt North Atlantic circulation changes in response to gradual CO2 forcing in a glacial cli-
mate state. Nature Geoscience 10 (7), 518523.
50 PART | II Climate changes during the Last Deglaciation in the Eastern North Atlantic region