Wody termalne rejonu Poznania

Abstract

THERMAL WATERS IN THE POZNAŃ REGION Summary In the Poznań region, there were hitherto made six drillings which enable studies on thermal waters in Lower Jurassic strata. The Lower Jurassic aquifer appears most promising from the point of view of exploitation of thermal waters in that area as well as the whole northern part of the Fore-Sudetic Monocline and it is one of the most advantageous hitherto found in the Polish Lowlands. In the Poznań area, top of water-bearing Liassic sandstones is situated at the depths of 800-1200 m and the Liassic is usually represented by usually up to 200 -300 m thick packets of sandstones separated by mudstones and claystones. Waters connected with that horizon belong to chlorine-sodium type, with mineralization changing from a few g/dm3 in southern part of this area to 70 g/dm3 in the northern part, and temperatures changing from 26°C in the south to 42°C in the north. Inflow of waters to boreholes is varying from a few to over 70 m3 per hour. The borehole Swarzędz IGH-1, made by the Geological Institute in the years 1981-1982, was the first of the hydrogeological ones to encounter Liassic aquifer in this region. Results of that drilling were found to be highly interesting and it appeared possible to start exploitation of thermal water in area of Poznań (the borehole is situated in that town, close to shore of the Malta Lake). Management of this borehole has been passed to the Poznań municipal authorities as the exploited water appeared suitable for recreation or medicinal purposes. Mineralization of the water equals 20.8 g/dm3 and the water may be classified as chlorine-sodium, bromine, barium. The temperature at the outflow is 42.2°C and the outflow - 76 m3/h, i.e. markedly higher than in parameter drillings.