Surowce węglanowe jury górnej na obszarze krakowsko-wieluńskim i ich znaczenie przemysłowe

Abstract

Przedstawiono warunki występowania utworów węglanowych jury górnej na tle ogólnej budowy geologicznej regionu Podano charakterystykę litologiczną i petrograficzną tych skal oraz - na podstawie ponad 2 tys. analiz - omówiono ich własności chemiczne i fizyczno-mechaniczne. W oparciu o powyższe dane dokonano oceny przydatności skał węglanowych dla potrzeb gospodarczych: w zależności od możliwości zastosowania wydzielono siedem odmian surowcowych. Przedstawiono również stan rozpoznania i wykorzystania surowców węglanowych tego regionu oraz wskazano obszary perspektywiczne i kierunki dalszych poszukiwań.UPPER JURASSIC CARBONATE RAW MATERIALS OF THE CRACOW-WIELUŃ JURA CHAIN AND THEIR INDUSTRIAL SIGNIFICANCEUpper Jurassic rocks crop out at distance of 100 km in the Cracow-Wieluń Jura Chain. In most northern part of that area they crop out in the vicinities of Burzenin. Further southwards the zone of outcrops may be traced in the vicinities of Wieluń and it passes through Kłobuck, Częstochowa, Żarki, Zawiercie, Olkusz and Cracow.The raw material deposits of the Upper Jurassic of the Cracow-Wieluń Jura Chain are mainly connected with the Oxfordian and, to some degree, Kimmeridgian carbonate rocks. Limestone facies generally predominates throughout the area, being accompanied by marly facies only in the Lower Oxfordian, uppermost Upper Oxfordian and Kimmeridgiim (Fig. 1).The Lower Oxfordian comprises alternating marly limestones and clay marls. This complex, 6 to 15 m thick, is characterized by large concentrations of sponges. The rocks represent complete raw material of cement industry. They are nowhere quarried separately but together with Middle Oxfordian limestones in quarries of the Wiek, Wysoka and Górka cement plants. The Middle Oxfordian is mainly represented by spongy platy limestones with flints, passing upwards into massive limestones. On account of high quality they represent good raw material for several industries: the above mentioned cement plants, lime burning (Złota Góra) and building industry (Wielepice). Total thickness of the Middle Oxfordian is estimated at 70 - 150 m.Lower part of the Upper Oxfordian comprises massive limestones and the upper - lithographic, chalky and marly limestones. Their industrial quality is similar to that of the Upper Oxfordian and they are quarried for the Warta and Rudniki cement plants, lime plants (Trębaczów, Rudniki, Mydlniki), soda industry (Zakrzówek) and, on a smaller scale, as building material. Specific raw materials connected with the Upper Oxfordian include chalky limestones and massive, porous ones named travertines. On account of their properties the former are used in chalk industry (Działoszyn - Kredówka, Wąsosz), mainly in production of technical and fodder chalk, and the latter - as unique lining material in building industry. The thickness of the Upper Oxfordian is estimated at 230-400 m.Carbonate Lower Kimmeridgian rocks occur in northern and southern part of the area. They are mainly calcareous-marly, representing complete raw material of cement industry. At the south, conglomerates and marls assigned to the Kimmeridgian are known from the exposure at Sudoł near Cracow.Depending on facies, in the Maim of the Cracow-Wieluń Jura Chain were differentiated platy, massive, and layered limestones representing three main Iithological types, i.e.: micritic, grainy micritic, and grainy micritic and sparry limestones.From the point of view of possibilities of use, the following raw material varietes were differentiated: platy, massive and layered, chalky and marly limestones, marls, "travertines" representing a specific  variety of the massive limestones, detrital and light limestones. Tables 1-6 show their chemical composition. Chalky limestones are characterized by the most homogenous chemical composition and the highest content of Cao of all these varietes, and marls - by the lowest content of CaO.Carbonate rocks of the Cracow-Wieluń Jura Chain may be widely used in various industries on account of their chemical composition and physico-mechanical properties. At ,present there are known 54 deposits of these rocks, 21 of which are currently exploited (Fig. 3). The evaluation of deposit perspectives made it possible to delineate 9 perspective areas of industrial and 7 others of local significance, with resources 10 times greater than the proven resources of that area (Fig. 4). This forms the basis for further rational development of industry in the whole area.