## 5 Discussion
### Tectonic Setting
In addition, another inquiry was conducted excluding samples whose CIA was less than 30. In the diagram (Figure 13b), the results show that the samples are less scattered, but in the case of Fe and Mg oxides versus Al and Si oxides (Figure 13d), there is no obvious difference. It bears emphasizing that chemical weathering does not play a significant role in the tectonic discrimination functions. However, some Badenian samples from the Tunjice Hills fall within the range of the continental island arc field (Figures 10a and 13a,b). This may be related to active intra-plate calc-alkaline volcanism in the Middle Hungarian Zone. Various processes, such as mantle plumes of hot rock from the Earth's mantle or thinning of the lithosphere resulting in the melting of the mantle [120], may also affect sedimentation in the western part of the PBS. The inaccuracy of these diagrams has already been discussed [121]; therefore, great caution should be exercised when using and relying solely on these discriminant diagrams. However, the diagrams were found to be a good indicator for determining the source material in the southwestern part of the PBS [25]. Figure 13: **(a,b)** Bivariate plot of TiO\({}_{2}\) versus Fe\({}_{2}\)O\({}_{3}\) + MgO diagram for the Tunjice Hills sedimentary rocks after Bhatia [68]; **(c,d)** bivariate plot of Al\({}_{2}\)O\({}_{3}\)/SiO\({}_{2}\) and Fe\({}_{2}\)O\({}_{3}\) + MgO diagrams for the Tunjice Hills sedimentary rocks after Bhatia [68]; **(a,c)** diagrams exclude samples with CIA > 80; **(b,d)** diagrams exclude samples with CIA > 80 and CIA < 30. The legend of the samples is shown in Figure 7. Explanatory notes: a—oceanic island arc, b—continental island arc, c—active continental margin, d—passive margin. Interpretation of Tectonic Setting of the Tunjice Hills (Western Central Paratethys)  
Various tectonic processes influenced the development of the studied area from the Miocene onwards, starting with the collision of the Adriatic and European lithospheric plates [20; 35; 36]. Considering that the Tunjice Hills are located at the western margin of the PBS at the conjunction of the Alps and the Dinarides, it can be emphasized that the results suggest that both rifting and collision played an important role in sedimentation in the Tunjice Hills during the Early and Middle Miocene. The basement of the PBS consists of ALCAPA (Alpine-Carpathian-Pannonian) and Tisza-Dacia mega-units and a Dinaridic tectonic unit [18; 29; 34]. The movement of the Adriatic-European plate, which triggered the Alpine collision, caused the activity of several faults, folds, and overthrusts in the area of the junction between the Alps and the Dinarides [122]. The collision caused pronounced changes: dextral movement of the Paradigm Fault (PAF) over 100 km during the Miocene [107; 123; 124], the thrusting of the External Dinarides, which is estimated to be post-Eocene and Early Miocene in age [125; 126], and the activation of the Sava fault, resulting in the folding of the Late to Middle Miocene strata [106]. According to recent studies [127], these faults are still active. The collision was one of the reasons for subduction, subsidence and extension of the lithosphere that led to the evolution of the back-arc type PBS in the late Early Miocene. Extension led to the thinning of the crust and subsidence and formation of a back arc-type basin [32; 61; 128; 129; 130; 131; 132]. The influence of the passive margin, connected with the formation of the PBS and the impact of arc setting were not expected in the Early Miocene sedimentation in the Tunjice Hills. The explanation of the arc setting is not certain. It is possible that volcanic activity in the Oligocene (Smrekovec complex) influenced sedimentation at the beginning of the Early Miocene. However, sedimentation in the Middle Miocene may be related to volcanic activity in intra-plate settings near the Middle Hungarian Zone.