## 5 Discussion
### Paleenvironmental Interpretation  
The Lake Vouliagmeni sediment record displays continuous sedimentary cycles of endogenic varve sedimentation, interrupted by non-laminated deposits (Figure 8). The lake is located in a tectonic, fault-controlled, karstic coastal landscape, and due to the interaction between the lake and the open sea, the distinction between the marine and lacustrine character of the varves is difficult to determine [19]. The occurrence of typically identical varve sections throughout the sediment sequence and the presence of _Lithophaga_ shells at the west coast of the lake [73] verify that the lake always interacted with the Gulf of Corinth. Additionally, the preservation/deposition of varves in the sediment sequence depends on sporadic water column density, stratification and anoxic conditions in the lake bottom that would decrease bioturbation [18]. During the formation of Vouliagmeni lake at the onset of the Holocene period [72], lake water conditions were not favorable for varve preservation until \(\sim\)10800 cal BP (Figure 8). Cluster C dominance in this period reflects high concentrations of Ca, Sr and S in the homogenous sediment. High seismicity rates during the Pleistocene-Holocene transition and the constant uplift of the Perachora peninsula during this period [72] must have been responsible for the laminae folding at \(\sim\)10,000 cal BP. Perennial humid conditions, inferred from a Rb/Sr increase, commence from \(\sim\)10,800 until \(\sim\)8000 cal BP and reach local maxima at \(\sim\)9000 and \(\sim\)9500 cal BP. An increase in water level due to the rising sea level [72] and possible high discharge of the karstic aquifer, suggested by high Ca/Sr values [127] during this time, is in agreement with other Eastern Mediterranean studies [128; 129; 130]. Two flood turbidites recorded during this time account for the re-oxygenation of the lake bottom water, as indicated by the increase in the Mn/Fe ratio. Both turbidite events are mainly associated with Cluster B, which reflects increased MS and HU values and increased precipitation in the area and sediment flux into the lake. Between 8000 and 7200 cal BP, the absence of varves highlights the positive balance between precipitation and evaporation ratio. Humid climatic conditions that could lead to a decrease in lake water salinity and alternation of water pH (rise to \(\sim\)9) combined with possible wind-driven mixing, as shown by a small increase in the Mn/Fe ratio [131], preclude stable stratification of the water column. Extensive freshwater inflow into the system could also lead to dislocation of the hypoxic/anoxic layer at the lake bottom, causing oxidation of the bottom surface that could potentially lead to bioturbation. Similar patterns of anoxic zone movement into upper layers have been recorded in the Amvrakikos Gulf [132; 133] and Aetoliko lagoon [134] in Western Greece. A transition to an arid phase around 7200-6800 cal BP, as suggested by a low Rb/Sr ratio, has also been recorded in other sites of the Eastern Mediterranean region [135; 136]. Cluster A, dominant during this phase, expresses arid conditions and is composed of detrital originated elements. Increased lamination frequency during this period is in comparison with the anoxic status indicated by low Mn/Fe (Figure 8). Coarser sediment indicated by high Zr/Rb and Si/Ti (Figure 8) may have accumulated at the lake bottom through a seismic event that also produced the laminae deformation at this point. However, no distinct event deposits were recognized in the sequence. Figure 8: Multi-proxy diagram including geochemical profiles of Rb/Sr Ca/Sr, Mn/Fe, Zr/Rb and Si/Ti, lamination frequency as measured through CT analysis, clustering stratigraphy exported through the constructed heatmap, Eastern Mediterranean precipitation and temperature model for mid- to late-Holocene as suggested by [137] and Turbidite deposits, as well as SSDS, recognized in the core. Turbidite deposits and SSDS were assigned with additional 2\(\sigma\) error as suggested by the age-depth model.