Polyhalite is a common constituent of many ancient evaporite sequences, especially Permian and Neogene ones, that is related to the Na-K-Mg-CI-S0 4 type of marine brines in those time intervals. There are four polyhalite deposits in the Zechstein of northern Poland, and more than ten polyhalite-bearing areas in the adjacent part of Russia, and they are commonly accompanied by K-Mg chlorides. Most polyhalite occurrences are related to the upper part of the Lower Werra Anhydrite and in most cases, polyhalite deposits are concentrated at the sulfate platform close to its boundary with platform slope, where they can pass horizontally into polyhalite beds occurring in the Oldest Halite. The bromine content in samples of the Oldest Halite ranges from 40 -120 ppm and the composition of fluid inclusions in halite are characteristic of halite precipitated from seawater concentrated to the early and middle stages of halite precipitation. The 8 180 and 8 34S values for sulfates are 10.03%0 -13.50%0 and 10.03%0 -12.14%0, respectively, and the 8 37CI values for halites from -0.1 %0 to +0.4%0 support their marine origin. Bromine distribution in the Oldest Halite and the occurrence of anhydrite intercalations indicate fluctuations of the brine density during the Oldest Halite deposition. The formation of polyhalite was preceded by the syndepositional dehydration of the original gypsum deposit and it appears that the anhydrite was then transformed to polyhalite by reaction with marine brines more evolved than those from which precipitated precursor calcium sulfate minerals. These concentrated brines could have been derived from the evaporation of marine brines and/or inflow of K-and Mg-rich brines that were formed in nearby shallow salt pans occurring in sulfate platform areas and thus sulfate platform areas and adjacent slopes of those platforms were predestined for polyhalite formation.

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Tre : S one jeziora oraz z o a ewaporatów jezior s onych w Turcji s wa nym ród em chemicznych surowców mineralnych. Pozyskuje si z nich g ównie: borany, w glany sodu, siarczany sodu oraz sól (chlorek sodu). Jeziora s one p askowy u anatolijskiego s zró nicowane pod wzgl dem chemizmu wód i warunków ewaporacji. Równie neoge skie (trzeciorz dowe) z o a ewaporatów jezior s onych w tym regionie charakteryzuj si specy cznym, cz sto unikatowym sk adem mineralnym. Zapoznanie si z warunkami ewaporacji i sedymentacji w s onych jeziorach oraz z budow geologiczn i eksploatacj z ó ewaporacyjnych jezior s onych by o celem geologiczno-górniczego seminarium Polskiego Stowarzyszenia Górnictwa Solnego (PSGS), które odby o si w Turcji w dniach od 7 do 14 wrze nia. Na trasie wyprawy znalaz y si : s one jeziora Salda i Tuz, z o e i kopalnia boranów Kirka oraz z o e i kopalnia siarczanów sodu Çayirhan. Podczas seminarium odwiedzono równie : miejscowo Pamukkale z gor cymi ród ami, z których krystalizuj trawertyny, z o a znanych od czasów staro ytnych marmurów w rejonie Iscehisar-Afyon oraz p askowy Kapadocji ze s ynnymi formami erozji i wietrzenia.

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Analysis of archive and published geological, geochemical and petrological data on composition of potash-bearing units (Older Potash [K2] and Younger Potash [K3]) of the Polish Zechstein (Late Permian) sections (mainly sampled pro les form three salt diapirs located in central Poland: Góra, K odawa, Mogilno, and additionally for petrology from Inowroc aw diapir as well as some data from the stratiform potash occurrences in the Foresudetic area in SW Poland) enabled to de ne content intervals and data statistic of main chemical components of both potash units as well as a type and content of determined evaporate minerals composed them.