Paleoenvironmental reconstruction of the last interglacial-glacial cycle of the quaternary in Central Europe applying a multi-proxy approach investigating loess-paleosol sequences

  • Paläoumweltrekonstruktion des letzten interglazialen-glazialen Zyklus des Quartärs in Zentraleuropa anhand einer Multiproxyanalyse von Löß-Paläoboden-Sequenzen

Krauß, Lydia; Lehmkuhl, Frank (Thesis advisor); Eckmeier, Eileen Sandra (Thesis advisor)

Aachen (2017)
Dissertation / PhD Thesis

Dissertation, RWTH Aachen University, 2017

Abstract

Anatomically modern humans are and always have been dependent on their climatic and environmental habitat. The presented study is part of the Collaborative Research Centre (CRC 806), which is funded by the DFG (Deutsche Forschungsgemeinschaft). The overall aim of the CRC 806 is the analysis of the dispersal of anatomically modern humans from East Africa towards Europe during the Upper Pleistocene. Reconstructing paleoenvironmental and paleoclimatic conditions contributes to that aim. In terrestrial environments loess-paleosol sequences often represent the best accessible and possibly the most complete archives of the Quaternary. As a contribution to improve the knowledge of past environmental and climatic dynamics, the presented study focused on the reconstruction of paleoenvironmental dynamics during the last interglacial-glacial cycle of the Quaternary in Central Europe by investigating loess-paleosol sequences via a multi-proxy approach. The climatic influence of the Atlantic Ocean led to generally larger disturbances, unconformities, and a varying preservation of layers in loess-paleosol sequences of Western and Central Europe compared to more continental regions, like the Carpathian Basin. As a consequence, the investigated profiles show differing characteristics. All investigated sections are covering varying time frames with varying sedimentological compositions, preservation of layers, and unconformities. Not only climatic conditions contributed those variations. Additional factors are involved, like the general geomorphological setting (e.g. slope angle and the exposure direction), and characteristics of the source area where the accumulated material originated from. The main loess-paleosol sequences of the presented study were located in the northern Harz foreland (Hecklingen and Zilly), the Neckar Basin (Talheim and Frankenbach) and the Franconian Jura (Attenfeld). The loess-paleosol sequences of the northern Harz foreland are located close to the maximum extent of the former Fennoscandinavian ice sheet during the Upper Pleistocene. During the glacial phases of the Middle Pleistocene the region was cover by the ice sheet. This prevented the preservation of aeolian sediments from the Middle Pleistocene and subsequently, loess-paleosol sequences only cover the last glacial. In contrast, the Neckar Basin and the Franconian Jura belonged to the periglacial during the Middle Pleistocene resulting in the preservation of a larger time span within the loess-paleosol sequences. However, the study focused solely on the Upper Pleistocene sediments to enlarge the possibility of comparability. During MIS 3, anatomically modern humans dispersed into wide parts of Central Europe under probably interstadial conditions. The profiles of the Neckar Basin and the northern Harz foreland show phases of soil development for that timeframe. The Attenfeld profile (Franconian Jura) shows an unconformity for that period. However, several phases of soil development connected to the MIS 3 were recorded by other studies around 150 km upstream the Danube River. Assuming that in Attenfeld MIS 3 and older sediments were eroded latest during the beginning of MIS 2, interstadial conditions might be valid for the region, too. The beginning of MIS 2 is marked by an erosion phase in all profiles. With regard on modern human settlements, this implicates a deterioration of environmental and climatic conditions with decreasing temperatures but still moist conditions that let to stronger impact events, like storms and subsequently, erosional events. With the increasing of aridification aeolian sediments accumulated containing only signs of initial soil development phases. Those sediments are preserved in varying resolutions in all profiles. Between 26 and 19 ka environmental and climatic conditions declined further in connection with the last maximum extent of the Fennoscandinavian ice sheet and Alpine glaciers (LGM). In the northern Harz foreland, this is characterized by signs of an elevated frequency of strong dust storm events under easterly wind conditions. In The Neckar Basin and in Attenfeld, no indication for a higher frequency of easterly winds can be observed. Last cover loess sediments (19 ka and 14 ka) show no signs of easterly wind direction in the northern Harz foreland anymore and therefore probably mark the retreat of the Fennoscandinavian ice sheet. With increasing more favorable climatic and environmental conditions the development of recent soils was initiated. As a result of further improving climatic and environmental conditions during the Holocene modern humans resettled Central Europe paving the way for today’s societies.