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

Grunert P, Tzanova A, Harzhauser M, Piller WE - Glob Planet Change (2014)

Bottom Line: U(K') 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 revealed palaeoclimatic pattern shows a strong correlation with isotope event Mi-1b in deep-sea δ(18)O 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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Earth Sciences, University of Graz, NAWI Graz, Heinrichstraße 26, 8010 Graz, Austria.

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. U(K') 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 δ(18)O 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.

No MeSH data available.


Localities in the NAFB evaluated for UK'37. GEO = St. Georgen 1, GU = Gurlarn, HM = Höhenmühle, HO = Hochburg 1, OS = Ottnang-Schanze, SE = Straß-Eberschwang, US = Untersimbach. Distribution of Cenozoic sediments in the NAFB study area is indicated in dark grey colour.
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f0005: Localities in the NAFB evaluated for UK'37. GEO = St. Georgen 1, GU = Gurlarn, HM = Höhenmühle, HO = Hochburg 1, OS = Ottnang-Schanze, SE = Straß-Eberschwang, US = Untersimbach. Distribution of Cenozoic sediments in the NAFB study area is indicated in dark grey colour.

Mentions: 22 samples from seven middle Burdigalian (lower to middle Ottnangian) localities in the central part of the NAFB in north-eastern Austria and south-eastern Germany have been used for SST reconstruction from alkenones in the present study (Table 1; Fig. 1). The selected sites consist of borehole and outcrop sections for which extensive information on stratigraphic constraints is available from previous studies (see below).


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

Grunert P, Tzanova A, Harzhauser M, Piller WE - Glob Planet Change (2014)

Localities in the NAFB evaluated for UK'37. GEO = St. Georgen 1, GU = Gurlarn, HM = Höhenmühle, HO = Hochburg 1, OS = Ottnang-Schanze, SE = Straß-Eberschwang, US = Untersimbach. Distribution of Cenozoic sediments in the NAFB study area is indicated in dark grey colour.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4375607&req=5

f0005: Localities in the NAFB evaluated for UK'37. GEO = St. Georgen 1, GU = Gurlarn, HM = Höhenmühle, HO = Hochburg 1, OS = Ottnang-Schanze, SE = Straß-Eberschwang, US = Untersimbach. Distribution of Cenozoic sediments in the NAFB study area is indicated in dark grey colour.
Mentions: 22 samples from seven middle Burdigalian (lower to middle Ottnangian) localities in the central part of the NAFB in north-eastern Austria and south-eastern Germany have been used for SST reconstruction from alkenones in the present study (Table 1; Fig. 1). The selected sites consist of borehole and outcrop sections for which extensive information on stratigraphic constraints is available from previous studies (see below).

Bottom Line: U(K') 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 revealed palaeoclimatic pattern shows a strong correlation with isotope event Mi-1b in deep-sea δ(18)O 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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Earth Sciences, University of Graz, NAWI Graz, Heinrichstraße 26, 8010 Graz, Austria.

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. U(K') 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 δ(18)O 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.

No MeSH data available.