Kraków Saltworks deposits

Salt exploitation history is connected in Poland, with the Miocen marine deposits filling the Pre-Carpathian basin. The salt series thickness varies from 250 m in Wieliczka up to 1500 m close to Wojnicz. It is built of five cyclothems, that is sedimentation cycles, beginning from aggregated  and argillaceous rocks (sandstones, mudstones, claystone), argillo-calcerous and anhydrite claystone to anhydrites and halites. The Carpathian overthrust caused strong folding of the salt series and formed local concentrations of salt of industrial value. The Miocen halite deposits occure in the Carpathian forground, between Wieliczka (West) and Tarnów (East). The historical sources  of the 11th and the 13th centuries mention bestowments and privileges of salt  mining. The documents certify that salt exploitation has been continued in ”Wieliczka” and  ”Bochnia” salt mines for over 700 years. They belonged to the Kraków Salt Mines, that together with the Russian Salt Mines (Kałusz, Tyrawa Solna, Jasienica, Starasól, Stebnik, Modrycz, Solec, Sołotwina and Truskawiec) constituted the Royal Salt Mines. The salt mines brought profits for local people, tenants and the king. Archaeological investigations provide more and more proofs confirming salt exploitation in the area. About 3500 years BC. Bochnia area was already known as a place where salt was obtained by means of an evaporation method. Ancient coins dating back to the Emperor Hadrian times as well as chert and flint tools were found on slag heaps of the Russian Salt Mines.  Due to development of the bore-hole method in salt mining, wider exploitation of the Zechstein salt deposits, the old salt mines began to loose their importance. Currently they function mainly as tourist attractions and sanitariums. In Bochnia, the lowest levels (from the XVI to the X) have been backfilled and the historical part (from the level I to IX) has been adapted for touristic purposes. The ”Wieliczka” salt mine reaches the depth of 327 m. It has 9 levels and about 300 km of excavations (galleries, inclined drifts, exploitation chambers, salt lakes, shafts and pits). Most of them are open for tourists. 

Elaborated by the Geological Museum at the Faculty of Geology, Geophysics and Environmental Protection of the AGH University of Science and Technology, © all rights reserved

See also:
Halite with organic inclusions
Halite crystals
Halite crystals from Groty Kryształowe [Crystal Caves]
Halite crystals on the watering can