Commune: Tomaszów Mazowiecki (pow. tomaszowski, woj. łódzkie)
Framework element or context represented:
Spring in the Upper Jurassic limestones of the Szczecin-Łódź-Miechów Anticlinorium, Central Poland.
Primary geological/geomorphological interest:
Karst, vaucluse spring.
Comparative assessment justification:
The largest karst spring in the Polish Lowlands, representing relatively well recognized hydrogeological system and characterised by high discharge and high quality of water.
Protection status and accessibility:
Nature reserve “Niebieskie Źródła” (since 1961), located in downtowns of Tomaszów Mazowiecki, well accessible.
Character of site: Spring.
Area: 28.77 ha
Altitude: 154-157 m a.s.l.
Lithology: limestones, marls
Discipline: Geomorphology
Process Age: *all periods
Bedrock Age: Jurassic, *all periods
Description of primary interest:
Niebieskie Źródła (Blue Springs) is large vaucluse spring famous for its high discharge and clarity since the 19th century. It represents ascending spring connected with fault zone in the SW side of the Pilica Graben in the Upper Jurassic/Lower Cretaceous rocks. The spring is recharged from karst reservoir in the Middle Volgian limestones underlain by the Middle Volgian marly clays and overlain by the Lower Cretaceous clays. The aquifer strikes ESE-WNW and slightly dips to southwest. The waters infiltrating southeast of the Niebieskie Źródła spring, flow along the beds strike towards the fault zone, where they are shielded by the Upper Cretaceous rocks and forced to ascent and escape. Dye tracing test documented hydrogeological connection of the spring with karst depressions located in Wąwał, 3 km to ESE, and very high speed of the underground flow (higher than 0.007 m/s), indicating karst nature of the aquifer. Its recharge with waters of the Pilica river (situated close to the spring basins) is questionable. The water discharge, that reached 220 dm3/s in the first half of the 20th century, decreased to less than 70 dm3/s periodically between the sixties and eighties and oscillated about 70-80 dm3/s in the last years of the century. The main reason of the spring yield decreasing was groundwaters exploitation in the vicinity. The spring water is characterised by very low mineralization and represents hydrogen carbonate-calcareous water of geogenic nature. In spite of the name, the water is colourless. Its chemical character is stable and quality (as drinking water) is very high. The limnocrenes represent two combined pools. Water exits on bottoms of the pools appear as white, sandy stains with “boiling waters“.
Literature:
KOBALCZYK A. 1998 – Gawędy znad modrych wód (in Polish only). Stow. Przyj. Pilicy i Nadpilicza. Piotrków Tryb., 220 pp. KUTEK J. 1994 – The Scythicus zone (Middle Volgian) in Poland: its ammonites and biostratigraphic subdivision. Acta Geol. Pol. 44, 1-2: 1-33. LEWIŃSKI J. 1933 – „Les Sources Bleues” et „Przepaść” près Tomaszów Mazowiecki (French sum.). Zabyt. Przyr. Nieożyw. 2: 69-73. MAŁECKA D. 1997 – Yield changes of the Niebieskie Źródła springs, their reasons and effects (English sum.). Acta Uniw. Lodz., Folia Geogr.-Phys., 2: 95-114. MAŁECKA D., MAŁECKI J. 1998 – Warunki hydrogeologiczne i hydrochemiczne oraz określenie działań mających na celu ochronę rezerwatu „Niebieskie Źródła (in Polish only). Monogr. Kom. Gosp. Wodn. PAN, 14, Oficyna Wyd. Politechn. Warsz., Warszawa, 67 pp. MAŁECKI J. 1997 – Hydrochemical characteristic of the Niebieskie Źródła springs (English sum.). Acta Uniw. Lodz., Folia Geogr.-Phys., 2: 115-131. MELA S. 1992 – „Niebieskie Źródła” nature reserve (English sum.). Acta Uniw. Lodz., Folia Geogr., 16: 123-128. TOŃCZYK G., KLUKOWSKA M., JURASZ W., MARKOWSKI J. 2000 – The Niebieskie Źródła nature reserve as a subject of scientific research. Acta Univ. Lodz., Folia Limnol., 7: 3-17. TRZMIEL B. 1990 – Objaśnienia do Szczegółowej Mapy Geologicznej Polski 1:50 000, ark. Tomaszów Mazowiecki (667) (in Polish only). Wyd. Geol., Warszawa, pp. 67. URBAN J., WRÓBLEWSKI T. 1999 – Representative geosites of the Góry Świętokrzyskie (Holy Cross Mts.) and the Nida Basin, Central Poland. Pol. Geol. Inst., Special Papers, 2: 61-70. WITKOWSKI A. 1969 – Geological structure of the Tomaszów Syncline (English sum.). Prace Inst. Geol. 53, 123 pp.