# Trace Elements and Mineralogy of Upper Permian (Zechstein)
## 6 Results
### Mineral Composition of Potash-Bearing Deposits
The analysed potash-bearing deposits of PZ2 cyclothem (28 XRD analyses and 14 petrographic studies supplemented with archive data of four thin sections) contain (Table 4) common minerals (frequency 10-18%), such as: halite (Figure 12A,C), sylvite (Figure 12F), kieserite (Figure 12C,D), and anhydrite (Figure 12E). The frequent (6-8%) ones are: kainite, polyhalite (Figure 12E), and quartz. The rare (1-3%) minerals that were detected: bischofite (Figure 12F), bloedite, carnalite (Figure 12A), constedtite, gypsum, magnesite, talc, pyrite, boracite, and minerals of chlorite group (Table 4). Calcite, leonite, loewite, langbeinite, nantokite, picromerite, spodumene, starkey \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mineral Chemical Formula**} & \multicolumn{3}{c}{**Number (Percent) of Analyses with Detected Mineral**} & \multirow{2}{*}{**Sum (Percent) of Analyses with Detected Mineral**} \\ \cline{2-2}  & \multicolumn{2}{c}{**Cyclothem and Lithost stratigraphic Unit**} & & **Analyses with Detected Mineral** \\ \cline{2-2}  & **PZ1,** & **PZ2,** & **PZ3,** & **Da**\% \\  & **Polyhalites within A1d** & **Na2+K2 and K2** & **Na3+K3 and K3** & \\ \hline \multicolumn{2}{c}{* hematite} & \multirow{2}{*}{-} & \multirow{2}{*}{-} & \multirow{2}{*}{4 (1.57)} & \multirow{2}{*}{4 (0.75)} \\ \multicolumn{2}{c}{Fe\({}_{2}\)O\({}_{3}\)} & & & \\ \hline clay minerals & - & - & 2 (0.78) & 2 (0.37) \\ \hline Sum of mineral detections & 21 & 258 & 254 & 533 (100\%) \\ \hline \hline \end{tabular} Mineral formula after: * [95], *** [96], * [97].  
\end{table} 
Table 4: _Cont._  
Figure 11: Thin section study, Mieroszyno M-9 borehole, sample M-9/2, depth 770.72 m. Sample location on Figure 2. **(A)** Radial and tabular crystals of polyhalite (plh, grey) and anhydrite plates (anh, white), microscope image (II polars). **(B)** SEM image of analysed anhydrite and polyhalite crystals with microprobe results; **(C)** colour dots—analytic points. and celestite were sporadically identified. Secondary minerals after kieserite, such as hexahydrite (Figure 12D) and epsomite were, also noticed. Studied potash-bearing deposits of PZ3 cyclothem (55 XRD analyses and 15 petrographic studies supplemented with archive data of two thin sections) evidenced (Table 4) that common minerals (frequency 10-19%) are halite, carnalite, kieserite, and anhydrite (Figure 12B). The frequent (>9%) minerals are kainite and sylvite, and the rare (1-2%) ones are bischofite, calcite, langbeinite, magnesite, polyhalite, and hematite. Sporadically, the following were registered: berlinite, hexahydrite, hexahydroborite, leonite, nantokite,  
Figure 12: Main minerals of Zechstein potash-bearing deposits (thin sections, X polars). (**A**) Twinned carnalite crystals within halite-sylvite mass (black). Older Potash (K2) unit, Inowrocław salt dome. (**B**) Large carnalite (ca) and fine twinned kieserite (k) crystals within halite (h). Younger Potash (K3) unit, salt mine KLODAWA S.A., NE-SW gallery, mine level 600 m. (**C**) Twinned kieserite crystals within halite-sylvite mass (black). Older Potash (K2) unit, Damashawek B well, depth 706.5 m. (**D**) Kieserite crystals (k) transformed into hexahydrite and epsomite (he + ep), halite-sylvite background (black). Older Potash (K2) unit, G-42 well, depth 1720 m. (**E**) Fine polyhalite crystals (p) framed by large anhydrite (an) and smaller kieserite (K) ones. Older Potash (K2) unit, M-34 well depth 487 m. (**F**) Needle crystals of bischofite, halite-sylvite background (black). Older Potash (K2) unit, Inowrocław salt dome. The common minerals (frequency 10 to <20%) registered in the studied Zechstein potash-bearing deposits are halite, kieserite, sylvite, and anhydrite. The frequent (5 to <10%) ones are carnalite, kainite, and sylvite, but the rare (1 to <5%) minerals are as follows: bischofite, calcite, langbeinite, magnesite, quartz, talc, pyrite, and minerals of the chlorite group (Table 4).