Building an amino acid geochronology for Quaternary Europe: a story of time and temperature.

The Quaternary period (the last 2.5 Ma) is marked by dramatic climate oscillations between cold glaciations and warmer interglacials. This shaped landscapes and influenced the evolution and dispersal of plant and animal communities. Europe has a rich Quaternary record, but a robust chronology is required to understand the impact of past climates on ecosystems. This knowledge may help predict the future effects of present-day climate change, including regional leads and lags. However, dating this record is challenging due to the often discontinuous nature of Europe’s terrestrial deposits. Additionally, most of the Quaternary falls beyond the limits of many radiometric dating methods.

Recent advances in amino acid dating, using intra-crystalline protein decomposition (IcPD) in bithyniid snail opercula, have enabled the construction of regional aminostratigraphies for Britain and the East European Plain. In this thesis, the use of IcPD is expanded across continental Europe, building regional frameworks for Germany, Hungary, and Poland. These frameworks include material from multi-aged sites spanning much of the Quaternary, anchored and validated at some sites by independent chronology. Expanding this dating approach to a wider geographical area has enabled the differences in IcPD extent due to temperature variations to be assessed to determine if any regional frameworks can be cross correlated to one another. Both climate and sub-surface temperature variables are shown to be important. Systematic differences due to sub-surface factors such as depth and the geothermal gradient show that material buried below 80 m is not directly comparable to near-surface deposits. Systematic differences in IcPD due to latitude and continentality in near-surface deposits have been assessed by exploring Quaternary temperature reconstructions. The systematic differences increased with age until racemic equilibrium was reached. This indicated that regions where colder conditions persisted for longer (and have had a higher degree of continentality) have opercula with reduced IcPD. This work has established and validated new aminostratigraphic frameworks across northern and central continental Europe, which can now be used to answer questions relating to Quaternary chronostratigraphy. In addition, this work has improved knowledge of the real-world effects of temperature on IcPD, laying the groundwork for a pan-European aminostratigraphic framework.