## 7 Depositional and Structural Evolutionary Model  
A depositional and structural evolution model of the study area, based on the sedimentological, geophysical and remote sensing data previously presented, as well as on previous studies in the Ionian zone [69; 72; 82; 83], is summarized in the conceptual model of Figure 13.  
Figure 13: Structural-depositional conceptual evolutionary model of the study area. The Platuria overturned syncline and the seismic profile equivalents are shown in block diagram (**k**) (red and yellow dashed-line rectangles, respectively). White question marks indicate unknown rock type below evaporites. During the Triassic-Early Jurassic, a shallow water, rifted carbonate platform (Figure 13a) dominated the area, represented in the stratigraphic record by Pantokrator limestones. The platform overlay a thick, flat-layered and almost isopachous evaporitic substratum of Early to Middle Triassic age. Poorly exposed Foustapidima limestones are considered as an intermediate unit between the evaporites and the shallow water carbonates [105; 106; 107]. The tectonic regime continued gradually to an extensional phase (Figure 13b), which has been considered as Pliensbachian in age (syn-rift phase) [71; 108]. Although these traditional interpretations placed the initiation of the syn-rift phase at this time, alternative interpretations support the existence of a Triassic rifting, based on field and seismic observations from NW Epirus, and lack of evidence for major faulting affecting the early Jurassic successions [82; 83] (Figure 14). Extension caused the gradual deepening of the basin, favoring the deposition of thin to medium-bedded pelagic limestones with chert intervals (Siniais and Louros Limestones). The segmentation of the platform in various blocks of a wedge-shaped geometry (Figure 13b) controlled the deposition of various lithological types (pelagic limestones, Ammonitic rosob beds, Posidonia shales, limestones with filaments), reflecting the heterogeneity of the depositional conditions across the basin [69; 72]. Additionally, the fault-controlled basin subsidence caused stretching and expelled the underlying salt by differential loading. In the Plataria area, Posidonia shales are the dominant lithologic type of the specific evolutionary stage. The accumulated sediments of phases 1 to 3 reached a significant thickness (see Figure 3: Foustapidima limestones 50-150 m, Pantokrator limestones >1000 m and syn-rift facies 20-200 m) for density inversion to occur, and are ready to trigger salt uprise by buoyancy forces when external forces are applied. Previous studies suggest that to initiate salt rise at least 650 m of sediment thickness is required for an overlying uncompacted carbonate platform, while for siliciclastics the required thickness is 1500 m [2; 109; 110]. The primary factor that influences the formation and evolution of salt structures is the differential loading, as suggested by [111; 112; 113], as well as the pattern of the sub-salt basement structure (i.e., uplift and slope flanks). At this stage (Figure 13c), a reactive mode of diapirism [19] can be implied, regarding that a buried salt layer formed a diapir in reaction to extension, favored by the aforementioned density contrast and/or differential loading. During extensional deformation, the overburden is lengthened and thinned, allowing salt to rise and fill the space below the tilted footwall fault blocks and later rise below the graben axis. The effect of salt diapirism is not yet clearly recorded in the sediment types (Figure 13d), where lower Cretaceous pelagic limestones (Vigla Formation) are deposited. At the deeper parts of the segmented sub-basins and on the tilted hanging-wall blocks, the Vigla shales were deposited. This tilting and the differentiation in the sedimentation pattern imply that diapiric intrusions (i.e., horn-type below the footwall blocks), which are activated by the extensional deformation of the syn-rift phase (reactive stage), start to play a key role in the sedimentation processes (Figure 14).