# Trace Elements and Mineralogy of Upper Permian (Zechstein)
## 5 Geology and Sampling of Potash-Bearing Deposits
### Potassium-Bearing Deposits of PZ3 Cyclothem  
The studied potash-bearing complex of PZ3 cyclothem is composed of two lithost stratigraphic units: the Transitional beds Na3+K3 and the Younger Potash (K3). The latter complex overlies the lower Younger Halite (Na3a) deposits and is covered by the upper Younger Halite (Na3b) unit (a case of the Klodawa salt dome) or by the Brown Zuber (Na3t) unit. The Younger Potash seam in the Fore-Sudetic area is 3-41 m thick and includes two rock salt beds with concentrations of polyhalite, sylvine, and anhydrite, separated by a single halite bed [86; 94]. The complex was accessible for sampling (207 samples taken from underground galleries and borehole cores) only in the four salt domes: Klodawa, Damaslawek, Gora, and Mogilno. The Transitional beds Na3+K3 in the Klodawa dome, ca 14.7 m thick, are built by grey fine crystalline rock salt, rhythmically stratified with fine and several thicker (0.3-5.3 m) beds of kieseritic carnallite. The Younger Potash (K3) unit, 20-120 m thick, is composed of interbeds of: (a) fine to medium crystalline rock salt, stratified with clay matter + anhydrite laminae and with laminae and nests of kieseritic carnallite, as well as (b) kieseritic carnallite layers with nests of coarse crystalline and transparent giant halite [93]. This potash unit is highly folded (Figure 9) in the central profile part (Figure 10). Figure 5: Core of Older Potash (K2) and Transitional beds Na2+K2 units in the profile of Damaslawek B well, depth interval 705.6–709.6 m. Red point—sample. Figure 6: Sampled parts of the Damaslawek A and B boreholes profiles with Na2+K2, K2, and K3, lithostratigraphic units, Damaslawek salt dome. Figure 7: Sampled parts of the G-41 borehole profile with K2 and Na3+K3 lithostrattigraphic units, Göra salt dome. Figure 8: Sampled parts of the M-33 borehole profile with K2 and Na3+K3 lithost stratigraphic units, Moginlo salt dome. This potash-bearing complex was sampled (187) in two galleries located at mine levels 600 m and 750 m of the underground salt mine KLODAWA S.A. [31,50]: Z3/1 profile (109 samples) and Z3/2 profile (78 samples; Figure 10). They are supplemented by geochemical data of six samples taken from two other galleries there [51]. The potash-bearing series of PZ3 cyclothem in the Damaslawek dome is represented by the Younger Potash (K3) deposits ca. 8.5-10 m thick, twice repeated in the Damaslawek A borehole profile (four samples; Figure 6). They are tectonically squeezed in rock salts of the Older Halite (Na2) and sulphates of the Main Anhydrite (A3). This series is dominated by grey-red medium crystalline rock salt with sylvite, either textureless or with anhydrite-clay matter flames. Some kieserite nests are covered with a white epsomite powder. Additionally, fine kainite admixture is observed. Repetition of beds of the Younger Potash unit was registered in many borehole profiles from the Gora dome. These beds are composed of rock salt and K-Mg salt layers, several  
Figure 10: Sampled profile Z-3/2 of K3 in a gallery of salt mine KLODAWA S.A., mine level 600 m, Klodawa salt dome.Location of Figure 9 was indicated in profile. Figure 9: Folded beds of rock salt (dark) and carmallite-kieserite (red and pink). The Younger Potash (K3) unit, Z-3/2 profile in the gallery of salt mine KLODAWA S.A., mine level 600 m, Klodawa salt dome. cm to over 5 m thick. The sampled (four samples) core intervals of G-41 borehole (Figure 7) represent a medium to fine crystalline \"hard\" kiseeritic langbeinite salt, built of repetitive thin layers of grey K-Mg salt and grey-orange rock salt. The main minerals are halite, kieserite, sylvite, langbeinite, and anhydrite, as well as a bitumen admixture. The sampled cores of two boreholes, M-33 (four samples; Figure 8) and M-35 (2 samples), represented the potash-bearing complex of PZ3 cyclothem from the Mogilno dome. In the M-33 profile is defined the Transitional beds Na3+K3, over 16 m thick and four times folded together with rock salts of the Older Halite (Na2) unit.