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Identifying abrupt climate change in SE Europe during MIS 12-11 based on high-resolution pollen analysis of the Tenaghi Philippon archive (NE Greece)

Subject Area Palaeontology
Term from 2016 to 2020
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 328730231
 
Final Report Year 2020

Final Report Abstract

Representing the most extreme glacial and interglacial periods of the Middle Pleistocene, Marine Isotope Stages 12 (478–426 ka) and 11 (426–367 ka) are key intervals to better understand the mechanisms responsible for climate variability during the Quaternary. Moreover, the close orbital analogy of MIS 11 to the Holocene can yield insight into the natural climate evolution of the present interglacial in the absence of human influence. On this basis, we have palynologically studied new core material from the iconic archive of Tenaghi Philippon (NE Greece) to unravel climate and terrestrial ecosystem variability in SE Europe during MIS 12 and 11. In total, 516 samples from the interval c. 490–335 ka were analysed at a centennialscale resolution (mean: 250 yrs), and compared with terrestrial and marine records from the Mediterranean and North Atlantic regions. For MIS 11, a c. 45-kyrs-long forest phase represents the longest forested interval at Tenaghi Philippon for the past 500 ka. The variability in the abundances of the dominant groups of trees (i.e., temperate and montane taxa, shrubs and Pinus) during this forest phase (c. 425–380 ka) is predominantly attributed to precipitation changes. Noteworthy, a transient increase of steppic taxa at c. 416 ka represents a cold and dry event within full interglacial conditions that is synchronous to cooling in the North Atlantic and may be equivalent to the widespread ‘Older Holsteinian Oscillation’ documented in central and western European records. The forest phase is followed by a series of forest-contraction events associated with the expansion of steppe biomes during the youngest intervals of MIS 11 and the transition to MIS 10. These events mark a considerable millennial-scale climate variability in SE Europe under conditions of increasing global ice-volume, which is comparable to terrestrial records from southern Europe and marine records from the North Atlantic. For MIS 12, a series of short-term forest contractions and expansions can be correlated with previously described forest dynamics in SE Europe, and SST and IRD fluctuations in the North Atlantic. The close correspondence between forest-expansion/contraction events at Tenaghi Philippon and interstadial/stadial events in the North Atlantic suggests a close coupling of the atmospheric circulation over SE Europe to the variability of the North Atlantic Ocean circulation. In addition, a wet phase during c. 448–455 ka may correspond to the timing of large-scale glacier formation on the mountain ranges of the Balkan Peninsula during the MIS 12, which was perhaps the most extensive during the Quaternary. The combination of the MIS 11–12 pollen data with the existing, partially unpublished, pollen record from Tenaghi Philippon has led to the generation of a continuous terrestrial record of SE European climate and ecosystem variability of the past 500 ka. The resolution of this record is 4–5 times higher than that of the iconic palynological record from Tenaghi Philippon, which is essential for a better understanding of Mediterranean forest resilience to climate change under different orbital boundary conditions as they were realized over the past four glacial/interglacial cycles.

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