Centennial-millennial scale ocean-climate variability in the northeastern Atlantic across the last three terminations

New Insights Into the Surface‐Ocean Dynamics of the Northeastern Atlantic Ocean Across the Marine Isotope Stage 7

“…Here, ANN technique was applied on the planktic foraminiferal assemblages to estimate the past SST, employing a back propagation neural network setting in the MATLAB © software version R2015b. We used the same ANN configuration as Singh et al (2023). And the networks were trained on the combined MARGO North Atlantic and the Iberian Margin planktic foraminiferal databases to reconstruct the annual SST (Kucera et al, 2005;Salgueiro et al, 2014Salgueiro et al, , 2020Singh et al, 2023).…”

“…The abundance variations of G. bulloides and G. glutinata are good indicators of changes in surface productivity and nutrient conditions, as both the species proliferate in the eastern boundary upwelling conditions of the North Atlantic Ocean (e.g., Ottens, 1992;Salgueiro et al, 2008;Singh et al, 2015Singh et al, , 2023Vautravers & Shackleton, 2006;Wilke et al, 2009). The abundance record of G. inflata combined with N. incompta indicates the PC influence (Salgueiro et al, 2008;Singh et al, 2015Singh et al, , 2023Vautravers & Shackleton, 2006), because these species show strong 2017). Tie-points (listed in Table 1) are marked by wine red arrows with solid and dashed ones denoting primary (Hodell et al, 2023) and secondary tie-points (this study) respectively.…”

“…Furthermore, the stadials associated with the glacial terminations TIII (∼243 ka) and TIIIa (∼221 ka) have prolonged durations as compared to the other five stadials (∼250, 230, 203, 196, & 192 ka) recorded in this study (Figure 4). We also record intervening brief phases of ∼4-6°C warming during the stadials at ∼243, 221, 203, and 192 ka, which characterizes the classic "W" shaped anatomy of the Heinrich stadials (e.g., Hodell et al, 2017;Jiménez-Amat & Zahn, 2015;Martrat et al, 2014;Naafs et al, 2013;Singh et al, 2023;Voelker et al, 2006;Ziemen et al, 2019). The classic "W" shaped anatomy of the stadials has been explained by the differential response of the European and Laurentide ice-sheets to the melting associated with the cold phases of Heinrich stadials (e.g., Hodell et al, 2017;Max et al, 2022;Singh et al, 2023).…”

“…We also record intervening brief phases of ∼4-6°C warming during the stadials at ∼243, 221, 203, and 192 ka, which characterizes the classic "W" shaped anatomy of the Heinrich stadials (e.g., Hodell et al, 2017;Jiménez-Amat & Zahn, 2015;Martrat et al, 2014;Naafs et al, 2013;Singh et al, 2023;Voelker et al, 2006;Ziemen et al, 2019). The classic "W" shaped anatomy of the stadials has been explained by the differential response of the European and Laurentide ice-sheets to the melting associated with the cold phases of Heinrich stadials (e.g., Hodell et al, 2017;Max et al, 2022;Singh et al, 2023). We, however, did not find this "W" shaped SST pattern during the stadials at ∼ 250, 230, and 196 ka.…”

“…Although, several studies have described the climatic oscillations during MIS 7 from continental Europe (e.g., Badertscher et al, 2011;Columbu et al, 2019;Denniston et al, 2018;Koutsodendris et al, 2023;Perez-Mejías et al, 2017;Roucoux et al, 2008;Spötl et al, 2008;Tzedakis et al, 2004Tzedakis et al, , 2009Wendt et al, 2021), North Atlantic Ocean (e.g., Channell et al, 2012;Hodell et al, 2008) and the Mediterranean region (e.g., Martrat et al, 2004;Toucanne et al, 2015), a few records are available from the SW Iberian Margin (Desprat et al, 2006;Hodell et al, 2023;Martrat et al, 2007;Roucoux et al, 2006;Singh et al, 2023;Tzedakis et al, 2004). Out of several existing terrestrial records, very few portray the entirety of MIS 8 deglaciation, MIS 7 interglacial complex and the subsequent return to glacial conditions of MIS 6 at high-resolution time-scales (e.g., Follieri, 1988;Koutsodendris et al, 2023;Reille et al, 2000;Wendt et al, 2021).…”