@ARTICLE{Szczepańska_Małgorzata_Carbonate_2003,
 author={Szczepańska, Małgorzata},
 number={No 1},
 journal={Gospodarka Surowcami Mineralnymi - Mineral Resources Management},
 pages={5-33},
 howpublished={online},
 year={2003},
 publisher={Komitet Zrównoważonej Gospodarki Surowcami Mineralnymi PAN},
 publisher={Instytut Gospodarki Surowcami Mineralnymi i Energią PAN},
 abstract={Carbonate concretions are rather widespread throughout the Carpathians, being present in various strata from Lower Cretaceous toMiocene. Theirmineral composition is strongly diversified, with prevalence ofcarbonates of iron, magnesium, calcium and manganese. They occur as lenses, bread-like forms and irregular layers, and their diameters range from some centimetres to some metres. The carbonate concretions of the Skole Unit are reported mainly from its shaly horizons and were found in the Spas, Dolhe, Ropianka, Variegated Shale, Hieroglyphic and Krosno Formations. Mineralogical investigations (optical microscopy and scanning electron microscopy, X-ray, OTA, chemical analyses) have allowed to distinguish several varieties ofthese concretions, typical for individual formations. The total ofcarbonates in the concretions, irrespective ofthe horizon in which they occur, range between 70 and 90%. Besides the carbonates, the concretions contain quartz and clay minerals, and some of them feldspars and pyrite. The concretions of the Spas Fm are sideroplesites (Szczepańska 1998). Their content of FeCO3 is the highest (50----60%) among all the concretions studied. The concretions of the Dolhe, Ropianka, Variegated Shale and Hieroglyphic Fm arc built of various mineral mixtures ofbi- or three-component carbonate solid solutions. High total contents ofFeCO3 andMnCO3, ranging from about 50 to 75%, are their common feature. In the Krosno Fm the content of FeCO3 decreases (to several percents), while the contents of CaCO3 and MgCO3 increase (CaCO3 to more than 40%). These concretions are composed of ankerite and Fe-dolomite (Rajchel, Szczepańska 1997). The content of simple carbonates in concretions from individual horizons of the Skolc Unit varies with the geological time. Similar relationships were reported by Narębski (1958) from the Westem Carpathians. He distinguished four geochemical facies, considering the type of sediments and the type of concretions contained in them. In the Skolc Unit, the Spas Fm can be included into Narębski's (1958) sideritc-pyrite facies, the Ropianka Fm into the siderite facies, the Dolhe, Variegated Shale and Hieroglyphic Fm into the variegated facies, and the Krosno Fm into the dolomite-ankcrite facies. The carbonate concretions studied arc of early diagenetic origin.},
 type={Artykuł},
 title={Carbonate concretions of the Skole Unit},
 URL={http://journals.pan.pl/Content/132475/PDF/3_GSM_19_1_2003_Szczepa%C5%84ska_Konkrecje.pdf},
 keywords={Carbonate concretions, spherosiderite, Flysh Carpathians, Skole Unit},
}