Mid-Burdigalian Paratethyan alkenone record reveals link between orbital forcing, Antarctic ice-sheet dynamics and European climate at the verge to Miocene Climate Optimum

Abstract

The Early Ottnangian Cooling (EOC), a distinct cold-spell in European climate at ~ 18 Ma preceding the Miocene Climate Optimum, is frequently reported in Paratethys records; however, the duration, magnitude, and underlying causes are poorly understood. A new palaeoclimatic data-set provides unexpected insights into this event.UK'37-based sea-surface temperatures > 24 °C between ~ 18.1 and 17.7 Myrs substantially exceed existing estimates, and indicate a significantly warmer European climate than previously assumed for this usually poorly recovered time interval. The EOC is expressed as an average drop of 2–3 °C in Paratethyan water temperatures between ~ 18.1 and 17.8 Myrs with two distinct cold snaps at ~ 17.86 Ma and ~ 17.81 Ma. The short duration of the EOC excludes Tethyan Seaway closure as its underlying cause, although the enhanced palaeoclimatic sensitivity of the Paratethys due to this palaeogeographic configuration potentially contributed to the magnitude of SST deterioration during the EOC. The revealed palaeoclimatic pattern shows a strong correlation with isotope event Mi-1b in deep-sea δ18O records, and we propose a tight palaeoclimatic link between the Southern Ocean and the Paratethys/Mediterranean realm as an alternative hypothesis. The interplay of modulations in the long-term (~ 400 kyrs) and short-term (~ 100 kyrs) eccentricity cycles most likely acted as pacemaker of this palaeoclimatic interaction.

Changing seas in the Early–Middle Miocene of Central Europe: a Mediterranean approach to Paratethyan stratigraphy

“…Consequently, the most logical connection to the Mediterranean is through the so‐called Trans‐Tethyan gateway (Kováč et al., ; Mandic et al., ) (Figure ). The Trans‐Tethyan gateway and the land–sea distribution of the Karpatian sea remarkably follow the contours of the Mid‐Hungarian Line (MHL; Géczy, ), suggesting that tectonic shear, accompanied by differential block rotations between the ALCAPA and Tisza‐Dacia mega‐units (e.g. Márton, Tischler, Csontos, Fügenschuh, & Schmid, ), played a major role by re‐connecting Central Paratethys basins with the open ocean, giving rise to the “Karpatian Sea” in the latest Early Miocene.…”

The middle Burdigalian in the North Alpine Foreland Basin (Bavaria, SE Germany) – a lithostratigraphic, biostratigraphic and magnetostratigraphic re-evaluation

“…According to Grunert et al (2010Grunert et al ( , 2012, the sandy-silty marls of the Ottnang-Schanze outcrop (see here Fig. 2) correspond to the lower part of the Ottnang Formation (onset of the regressive phase) and the suggested time interval falls within the lowermost part of NN4 (Grunert et al 2014).…”

“…Because of the rarity of radiometric age constraints and magnetostratigraphic stud-ies, the putative ages assigned to the stage boundaries can vary widely, and correlation with the standard GTS is still difficult (Krijgsman and Piller 2012). For example, the base of the Ottnangian is dated to 18.12 Ma in Grunert et al (2014), 18.2 Ma in and Krijgsman and Piller (2012), 18.25 Ma in Reichenbacher et al (2013), 18.5 Ma in Abdul Aziz et al (2010), and 18.7 Ma in Vakarcs et al (1998). According to Piller et al (2007), the regional Miocene time scale of the Central Paratethys is based on correlations with the global sea-level curve of Haq et al (1988) and the sequence stratigraphic cycles of Hardenbol et al (1998) (Fig.…”

The relationship between Neogene dinoflagellate cysts and global climate dynamics

“…alkenone data from the Paratethys Sea shows a 2 3 °C cooling between 18.4 and 17.8 Ma (Grunert et al, 2014). The Early Miocene is characterised by a 2.4 Ma eccentricity-paced benthic oxygen isotope record with distinct intervals of glacial-interglacial cycles operated on a 110 ky periodicity (Liebrand et al, 2017).…”