Lower Danube loess and millennial-scale paleoclimate changes: new approach, new outcome and new perspectives

Abstract

Loess-paleosol sequences are the most widespread terrestrial archives of Quaternary paleoclimate. Recent research carried out on multiple profiles from the Danube loess basins significantly improved our understanding of past environments, especially in the Lower Danube area, where loess-paleosol sequences and alluvial archives represent almost exclusively the main Pleistocene paleoenvironmental records.
Here we present a synopsis of the latest research carried out using detailed high-resolution sedimentological, geochemical and chronological approaches, including multi-method luminescence dating and tephrochronology of several loess profiles from the Lower Danube area. We provide detailed records of grain-size and loess geochemical composition, with the aim of reconstructing the paleoenvironment as well as complementing the luminescence based age models of these records through comparisons with other records, aided by the presence of volcanic ash beds (particularly the Campanian Ignimbrite), that allow for the building of reliable correlative age models. A series of environmental magnetic proxies provide information on the magnetic mineralogy, grain-size variations and trace the amplitude of past pedological influences that modulate the paleoclimatic significance of proxy data. Most parameters show distinct down-core oscillations that correlate well with regional shifts in paleoclimate. These features, visible also in the grain-size data are complemented by information from geochemical proxies that provide important insights into the nature of the depositional environment and origin of sediments.
Our new records are compared with regionally representative speleothem and marine stacks from the Black Sea, Mediterranean and the high-latitudes of the Northern Hemisphere. The comparison reveals consistent millennial-scale variability (e.g., fluctuations that resemble stadial-interstadial events) archived within the proxy data and identification of common features that may allow for the synchronization of records for most of the last glacial cycle, but also intriguing differences. The results also illustrate the value of a multiproxy approach in understanding sediment dynamics and variations in physical and chemical processes influencing/controlling loess-paleosol formation during rapid climate changes such as stadials and interstadials.

Resources

• http://pastglobalchanges.org/osm2017/downloads/osm-abstract-book-zaragoza-2017.pdf

Bibliography

Veres, D., Timar-Gabor, A., Obreht, I., Hambach, U., Zeeden, C., Bösken, J., Anechitei-Deacu, V., Marković, S., Lehmkuhl, F. (2017): Lower Danube loess and millennial-scale paleoclimate changes: new approach, new outcome and new perspectives. PAGES Zaragoza 2017 9.-13.5, Global Challenges for our Common Future: a palaeoscience perspective, Zaragoza, Spain