## 4 Results  
### Mineralogy  
The quantitative mineral composition of the samples is shown in Figure 4; the values can be found in Table S3. The quartz content of the Early Miocene samples varies up to 35.4 wt.%, albite up to 33.1 wt.% and calcite up to 45.4 wt.%. Dolomite ranged up to 24.4 wt.%, illite from 0.2 to 32.5 wt.%, muscovite from 0.3 to 15.6 wt.%, and montmorillonite from 0.2 to 29.6 wt.%. Kaolinite and pyrite content is low and varies up to 3.2 wt.% for kaolinite and up to 1.2 wt.% for pyrite. Cristobalite content varies up to 13.8 wt.%, but it is generally detected in lower amounts or not at all. The common content of clinochlore is up to 5.5 wt.%, but in one sample, its content is 54.2 wt.%.  
The majority of Badenian sediments contain quartz in amounts ranging from 12.5 to 55.3 wt.%, calcite in amounts ranging from up to 62.5 wt.%, and dolomite in amounts ranging up to 44.4 wt.%. Muscovite content varies from 1.8 to 23.6 wt.% and clinochlore up to 13.4 wt.%. Clay minerals occur frequently. Albite content varies from 0.9 to 12.9 wt.%, illite up to 33.3 wt.%, montmorillonite up to 6.1 wt.%, and kaolinite up to 4.7 wt.%. Other minerals (cristobalite, tridymite, microcline, anorthite, pyrite, hematite) commonly occur in amounts lower than 2 wt.%.  
The quartz content of the Sarmatian samples varies from 17.8 to 67.6 wt.%, calcite up to 28.6 wt.% and dolomite up to 46.4 wt.%. Muscovite content varies from 2.6 to 26.7 wt.%, clinochlore up to 9.1 wt.%, and albite from 1.4 to 9.7 wt.%. Clay minerals are common. Illite content varies between 0.8 and 19.2 wt.%, kaolinite content between 0.6 and 7.5 wt.%, and montmorillonite content up to 21.2 wt.%. Other minerals (tridymite, microcline, anorthite, pyrite, hematite) occur rarely and generally in amounts below 1 wt.%.  
The XRD patterns show the presence of large amounts of quartz in all samples and a slightly lower, but still very abundant, occurrence of calcite, muscovite, and albite. The weight ratio of quartz and calcite is often inversely proportional, but in some cases, their weight ratio is very similar, for example, in sample B13, where their weight ratio is almost equal. Significantly less calcite and dolomite and higher amounts of quartz, montmorillonite, kaolinite, and anorthite are determined in the Sarmatian samples than in the Badenian samples. Cristobalite is detected only in the Early Miocene samples. The amounts of other minerals in the Badenian and Sarmatian samples (see Figure 4) are similar.  
Figure 4: Quantitative mineral composition of samples in wt (%) in Tunjice Hills.  
Significant differences can be observed in the amount of quartz and albite, which is lowest in the samples from the early Miocene. There is a significant difference in sample E3, in which no quartz and calcite were detected and in which clinochore is abundant, and in sample E1, in which no albite was detected. The highest quartz values are found in the samples from the Sarmatian. There is generally very little calcite and dolomite in some samples from the Sarmatian, while montmorillonite is only present in a few samples from the early Miocene and the Sarmatian. The proportion of kaolinite, pyrite, muscovite, calcite and dolomite varies from sample to sample and the value is not tied to a specific group of samples.