This project aims to investigate the relationship between precipitation, temperature, and topsoil properties, particularly focusing on rock magnetic proxy data, across a broad climate gradient in the Danube catchment area. The research aims to decode spatial and temporal variability using multiple proxies and apply this knowledge to assess past interglacial climates.

Three main hypotheses guide the research:

Hypothesis 1: The project aims to establish a clear relationship between soil properties and climate proxies over a wider climate gradient than studied in a previous project. The research involves testing various rock magnetic climate proxies by analyzing soils developed on loess deposits along the Danube. Multivariate geophysical and geochemical analyses will be used, and statistical tools such as Principal Component Analysis and regression models will help identify systematic data structures.

Hypothesis 2: The study acknowledges potential differences in the composition of loess substrates due to varying provenance and sediment processes. The goal is to account for these differences using information about the background loess and integrating geochemical provenance indices into a multivariate approach. This approach will help determine the effect of substrate variability on the relationship between soil properties and climate proxies.

Hypothesis 3: Rock magnetic climate transfer functions work even in inhomogeneous substrate. Transfer functions developed for recent topsoils will be extrapolated into the past to reconstruct past climate parameters, such as precipitation and temperature, from interglacial soils and loess deposits.

The research will involve extensive sampling of approximately 100 loess sites along the Danube, encompassing a wide range of climate and substrate variations. Geophysical and geochemical analyses, including rock magnetism, colorimetry, and XRF geochemistry, will be performed on the samples to generate a comprehensive dataset. The data will be statistically analyzed and related to climate data, ultimately contributing to a better understanding of the relationship between soil properties and climate.

Field Campaigns:

• Southern Germany (March 3-4.2025):
  The first sampling campaign took place near Augsburg. The team collected 23 topsoil samples along a north–south transect in the Lech catchment, as well as more than 50 Eemian and Holocene soil samples from two profiles in the Bobingen gravel pit (Fig.1).
• Serbia (July 1–8, 2025):
  A total of 38 topsoil samples were collected along the Danube, along with 92 loess section (S1) samples from two profiles in Novo Orahovo and Kula (Fig.2) (northern Serbia), in collaboration with the Serbian research team.
• Southern Germany (July 14–18, 2025):
  An additional 34 surface samples were collected along the Danube River between Passau and Ulm (Fig.3)

Laboratory Work:
Samples from Germany have been analyzed in the rock-magnetic laboratory in Grubenhagen and in the grain-size laboratory in Hannover. Measurements of Serbian samples are currently ongoing. The next steps include XRF analysis of the collected samples and the preparation of future field campaigns in Austria, Hungary, and Romania.

Meanwhile, the research team is developing a comprehensive database for all collected materials and analyses, ensuring structured data management and long-term accessibility for ongoing and future investigations.

Preliminary results suggest that the Eemian in southern Germany experienced significantly higher precipitation than today.