Paleoclimatic and tephrostratigraphic potential of last glacial cycle south-eastern European loess-paleosol sequences

Abstract

Owing to the nature of their formation, loess-paleosol sequences are valuable in investigating past variability in long-term global dust dynamics. As the primary constituent of loess, mineral dust, a major component of global climate forcing and a proxy that, allows for direct comparison of loess data with chronologically better resolved ice and marine records. Motivated by the recent emergence of high-resolution data on Lower Danube loess-paleosol profiles covering the last glacial cycle, including secure identification of millennial-scale past climate variability, we explore possibilities and drawbacks in comparing regional paleoenvironmental response to millennial-scale climate variability for the last glacial cycle by comparing loess records with better established lacustrine and marine records from south-eastern Europe. We also discuss regional implications in defining an improved loess chronostratigraphic framework based on several lines of chronological evidence, including tephrochronology. As reliable chronological control is still the major limiting factor in exploring the full paleoclimate potential of loess, we discuss several tephra layers that would allow for isochronous tie-points with marine and lacustrine records and in validating the luminescence-based chronologies of loess records. For example, the Campanian Ignimbrite/Y-5 tephra forms the main chronologic/stratigraphic marker in western Eurasia for MIS 3 deposits. As the product of one of the largest Late Pleistocene explosive events in the Mediterranean region dated to 39-40 ka BP, it provides an independent basis for establishing age-depth relationships for the embedding deposits and for comparing records on a wider scale. Following its widespread occurrence in the Lower Danube loess records, we conducted a detailed chronostratigraphic survey of selected sites corroborated by the dating through (mainly) luminescence methods. The aim was to test for the reliability of the luminescence methods in that narrow age-range around 40 ka BP. We show that in general the luminescence age estimates would confirm that the volcanic ash occurrences represent a Topic 8: Climate change, climate dynamics and paleoclimate – 8c) Loess systems and the reconstruction of Pleistocene climate dynamics
167regionally synchronous depositional event, around 40 ka in age, as suggested by the detailed glass-shard chemical data, albeit significant differences have also been obtained.

Resources

• http://www.geobonn2018.de/assets/geobonn_2018_abstracts_12092018.pdf

Bibliography

Veres, D., Hambach, U., Obreht, I., Zeeden, C., Timar-Gabor, A., Bösken, J., Lehmkuhl, F., Marković, M., B., S. (2018): Paleoclimatic and tephrostratigraphic potential of last glacial cycle south-eastern European loess-paleosol sequences. Geobonn 2018, Living Earth, 2-6 September 2018, Bonn, Germany, Bonn, Germany