## 5 Discussion  
### Non-Destructive Proxies  
The comparison of medical CT with \(\upmu\)CT scanning reveals that both techniques are an effective and fast way for sediment core internal structure characterization. Laminae distinction, as well as event layers, could easily be determined through the proposed workflow. The main advantage compared to thin-section micromorphology examination is that, during thin section preparation, lamination disturbance and distention could lead to inaccurate measurements of lamination boundaries/thickness [45]. Processing of the acquired data is also much faster compared to thin section preparation and resin impregnation on the sediment samples, which would require much time to cover the whole sediment sequence. However, in the Lake Vouliagmeni sediment core, laminae sublayers could only be detected through microscopic analysis, which leads to the conclusion that the use of both methods is essential for thorough microstructural examination. Density is a crucial parameter in X-ray interaction with matter [100; 101; 102; 103]. Since CT scanners \"express\" this interaction with HU values, optimizing the output 3D rendered volumes with specific boundaries can provide information on the desired parameter. On the studied core, we used a range of HU values that would represent the white/aragonite-rich laminations and exclude the brown/black/organic-rich deposits. The principle behind this proposed method is similar to the one used by [104] to distinguish gastropod shells and calculate sediment versus shell percentage on a lagoon sediment core. The main drawbacks during CT analysis are that, depending on the lamination thickness, older CT systems may not provide the required resolution to address lamination boundaries. Furthermore, due to the massive data amount produced from even 1 m of the sediment core from the CT scanner (\(\sim\)4000 DICOM files), standard personal computers may not be adequate to create the 3D rendered volumes. Chemical weathering in the lake system is interpreted by variations in Rb/Sr ratio [105; 106; 107; 108; 109] (Figure 8). During matrix weathering and transport, Rb is a common substitution of potassium (K) in K-feldspars that comprise the crystal lattice of clay minerals. Alkaline elements like Sr and Ca enter the lake catchment either from an allochthonous source (carbonate weathering) or from autochthonous sedimentation inside the lake in the form of SrCO\({}_{3}\)[110; 111]. Both geochemical proxies present a near symmetrical distribution in the sediment sequence (Figure 8), with higher values indicating wet conditions in the study area, triggering extensive erosion and sediment flux in the lake. In limestone-rich environments, calcium precipitates in the form of Ca\({}^{2+}\) and CO\({}_{3}\)\({}^{2-}\) ions, especially under anoxic/hypoxic conditions [112; 113; 114; 115; 116]. The solubility of CaCO\({}_{3}\) decreases during dry periods, thus forming carbonaceous laminated deposits [117] if lake bottom conditions are favorable. Positive balance between precipitation and evaporation is characterized by higher values of Ca/Sr ratio [110] and lamination frequency (number of laminae/cm) in the sediment sequence (Figure 8), with aragonite accumulation occurring during dry seasons. Mn and Fe are positively affected by redox potential in the catchment, with Fe ions precipitating earlier than Mn ions due to decreased stability. Higher concentrations occur in oxidizing environments [108; 118; 119; 120; 121] or events in which the lake bottom is re-oxygenated. High values of Zr/Rb and Si/Ti are associated with coarser sediment material and biogenic silica (diatoms) in the sediment sequence [40; 122; 123; 124; 125; 126], while the clay fraction is mostly represented by allochthonous Rb accumulation. A correlation between elements with high atomic numbers like Zr and HU values has been recorded by [88], at the coarse base of turbidite deposits.