Wzorcowe profile bromowe cechsztyńskich soli kamiennych w Polsce i w Niemczech na przykładzie kopalni soli w Kłodawie i w Görleben
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Date
2008
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Wydawnictwo Naukowe UAM
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Standard bromine profiles of the Polish and German Zechstein salts (a case study from the Kłodawa and Görleben salt mines)
Abstract
Skonstruowano wzorcowy profil bromowy dla ogniwa solnego cyklotemu PZ2 (odpowiednik standardowego profilu bromowego utworów cyklu Z2 w Niemczech) oraz przedstawiono wstępne wyniki prac nad wzorcowym profilem bromowym dla ogniwa solnego cyklotemu PZ3. Porównanie profilu bromowego danego odcinka serii solnej z profilem wzorcowym całej serii solnej umożliwia określenie jego pozycji stratygraficznej w obrębie tego ogniwa wiekowego, a także pozwala na identyfikację struktur fałdowych w utworach solnych, co jest niezwykle przydatne w górnictwie, szczególnie podczas ługowania kawern. Przeprowadzono szczegółowe opróbowanie pięciu profili starszych soli kamiennych w kopalni soli Kłodawa (trzech na poziomie 600 m i dwóch na poziomie 750 m) oraz jednego profilu młodszych soli kamiennych (poziom 600 m). Opróbowanie utworów cyklu PZ2 objęło także tzw. „warstwy przejściowe” (Na2+K2) oraz starszą sól potasową. Badania były prowadzone równolegle przez dwa zespoły: zespół z Federalnego Instytutu Nauk o Ziemi i Surowców Naturalnych (BGR) z Hanoweru oraz zespół z Państwowego Instytutu Geologicznego w Warszawie. W pobranych próbkach oznaczono zawartość bromu oraz Na, Cl, K, Mg, Ca, SO4 i części nierozpuszczalnych w wodzie. Zawartość składników głównych została przeliczona na skład mineralny. Szczegółowe profile bromowe ogniwa starszej soli kamiennej, wykreślone w oparciu o dane z dwóch najdłuższych profili, wykazują duże podobieństwo. Trzy charakterystyczne odcinki odznaczające się określoną tendencją zmian zawartości bromu tworzą profil wzorcowy ogniwa soli starszych Na2. Skonstruowany profil wzorcowy dla soli cyklu PZ2 jest w części dolnej i środkowej bardzo podobny do standardowego profilu bromowego utworów Z2 opracowanego dla obszaru NW Niemiec. Profil bromowy opracowany dla soli cyklu PZ3 w Kłodawie znacznie różni się od profilu bromowego utworów cyklu Z3 w NW Niemczech.
The aim of the study was to develop a bromine standard profile of the Polish Zechstein 2 (PZ2) analogue to the German Z2 bromine standard profile. Studies of the bromine content in salts were realized in five sections of the Kłodawa salt mine (central Poland); samples were taken from the Screening Older Halite unit, the Older Potash unit, the “Transitional Beds” and the Older Halite units. The material was analyzed in the Polish Geological Institute for the content of Cl, insolubles in water and Br. German partners (BGR) analyzed the content of Na, K, Ca, Mg, Cl, SO4 and Br. Based on these components, the mineral composition and the bromine content of the halites were calculated. The Older Halite rocks are relatively pure rock salts with a NaCl content from 74 to 100% by weight; the bromine content in the halites varies between 31 and 341 µg/g halite. The “Transitional Beds” (Na2+K2) and the Older Potash (K2) units contain more sulphates (including secondary polyhalite). The Br content of the “Transitional Beds” varies from 76 to 269 µg/g. The highest concentrations correspond to those of potash salts and they vary from 275 to 974 µg/g in section III. In the lowermost beds of the Na2 unit, the occurrence of polyhalite and particularly the abnormal high bromine values (up to 150 µg/g) are probably due to the inflows of brines of higher salinity. The decreasing bromine values in the upper part indicate a reduced influence of external brines. The bromine distribution indicates that the Br content slightly increases in a long interval (10-120 m) from approx. 40 (60) to 90 (100) µg/g. The slight increase of the bromine trend can be interpreted as a normal evaporation progress and is consistent with the lower parts of the German Hauptsalz unit regarding the bromide value. In contrast to the German lower Hauptsalz, small amounts of polyhalite can be observed locally in the Kłodawa sections. Upwards, over an interval of a few meters, the bromine content rapidly increases to approx. 300 µg/g, indicating the dominance of evaporation in contrast to dilution by newly invading sea water and recycling of sediment. Neglecting the lowest part of the Older Halite (Na2) unit with the abnormal high bromine concentration and the altered top, the following characteristic trends can be recognized in its bromine profiles: (1) a subtle increasing bromine trend over a long vertical interval in the oldest layers reflecting ongoing sedimentation under conditions of continuous evaporation, (2) a very steep increase in the bromine values in the middle part of the profile, due to the fact that the basin did no longer participate in brine exchange, (3) small variations in the high bromine values of the overlying beds. The characteristics of the bromine standard profile enables stratigraphic correlation of the salt units with other localities. The bromine profile of the Younger Halite unit from the Kłodawa mine differs greatly from the German Z3 profile from the Görleben mine. The data presented here are preliminary; additional studies of some other sections in central Poland are required for developing a standard bromine profile for PZ3.
The aim of the study was to develop a bromine standard profile of the Polish Zechstein 2 (PZ2) analogue to the German Z2 bromine standard profile. Studies of the bromine content in salts were realized in five sections of the Kłodawa salt mine (central Poland); samples were taken from the Screening Older Halite unit, the Older Potash unit, the “Transitional Beds” and the Older Halite units. The material was analyzed in the Polish Geological Institute for the content of Cl, insolubles in water and Br. German partners (BGR) analyzed the content of Na, K, Ca, Mg, Cl, SO4 and Br. Based on these components, the mineral composition and the bromine content of the halites were calculated. The Older Halite rocks are relatively pure rock salts with a NaCl content from 74 to 100% by weight; the bromine content in the halites varies between 31 and 341 µg/g halite. The “Transitional Beds” (Na2+K2) and the Older Potash (K2) units contain more sulphates (including secondary polyhalite). The Br content of the “Transitional Beds” varies from 76 to 269 µg/g. The highest concentrations correspond to those of potash salts and they vary from 275 to 974 µg/g in section III. In the lowermost beds of the Na2 unit, the occurrence of polyhalite and particularly the abnormal high bromine values (up to 150 µg/g) are probably due to the inflows of brines of higher salinity. The decreasing bromine values in the upper part indicate a reduced influence of external brines. The bromine distribution indicates that the Br content slightly increases in a long interval (10-120 m) from approx. 40 (60) to 90 (100) µg/g. The slight increase of the bromine trend can be interpreted as a normal evaporation progress and is consistent with the lower parts of the German Hauptsalz unit regarding the bromide value. In contrast to the German lower Hauptsalz, small amounts of polyhalite can be observed locally in the Kłodawa sections. Upwards, over an interval of a few meters, the bromine content rapidly increases to approx. 300 µg/g, indicating the dominance of evaporation in contrast to dilution by newly invading sea water and recycling of sediment. Neglecting the lowest part of the Older Halite (Na2) unit with the abnormal high bromine concentration and the altered top, the following characteristic trends can be recognized in its bromine profiles: (1) a subtle increasing bromine trend over a long vertical interval in the oldest layers reflecting ongoing sedimentation under conditions of continuous evaporation, (2) a very steep increase in the bromine values in the middle part of the profile, due to the fact that the basin did no longer participate in brine exchange, (3) small variations in the high bromine values of the overlying beds. The characteristics of the bromine standard profile enables stratigraphic correlation of the salt units with other localities. The bromine profile of the Younger Halite unit from the Kłodawa mine differs greatly from the German Z3 profile from the Görleben mine. The data presented here are preliminary; additional studies of some other sections in central Poland are required for developing a standard bromine profile for PZ3.
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Keywords
standardowe profile bromowe, standard bromine profiles, sól kamienna, rock salt, Cechsztyn, Zechstein (Upper Permian)
Citation
Geologos vo. 14 (1), 2008, pp.73-90.
ISBN
978-83-232187-4-6