Orbital and glacial/interglacial forcing reflected by integrated environmental magnetic and colorimetric parameters of a loess-palaeosol sequence in the middle Danubian Basin for the last 430 ka

Loess-palaeosol sequences (LPSs) are valuable records of Quaternary environmental change especially in the northern hemisphere. In Eurasian LPS, the alternation of loess and palaeosol intervals reflects the uninterrupted but fluctuating dust deposition during the Quaternary and the fluctuations of temperature and precipitation responsible for the formation of palaeosol horizons. At Zemun (Middle Danube Basin, Serbia), a studied LPS covers four interglacial-glacial cycles. We use standard colorimetric data, containing luminance (L*), redness (a*) and blueness (b*), backscattered wavelength intensities of the visible light spectrum (400-700 nm), and first derivatives of the measured spectra indicative for assessing relative hematite and goethite contents. Environmental magnetic data comprise indicators for intensity of pedogenesis (frequency dependence of the magnetic susceptibility) and for magnetic mineralogy (high- and low-field susceptibilities) of 490 samples. Age models of LPSs are often created by the direct correlation of low-frequency susceptibility records with global paleoclimate stacks (in particular the LR04 stack, Lisiecki and Raymo, 2005) and global ice models (Imbrie and Imbrie 1980), especially when absolute dating techniques are limited. Here we apply several spectral analysis techniques for investigating orbital forcing at the Zemun site. The resulting age model goes back to ~430 ka, and shows distinct differences between proxy records. These differences are presumably caused by different sensitivities of the employed palaeoenvironmental proxy parameters reflecting their non-linear response to changing climate conditions.