Carbonate concretions of the Moravsko-Slezské Beskydy Mountains (Czech Republic)

The carbonate concretions up to 1 m in diameter occur in the Cretaceous and Paleogene formations of the Silesian Unit in the Moravskoslezské Beskydy Mountains. Three concretions from three different formations were analyzed (Veřovice and Istebna formations and Albian-Cenomanian of the Kelč Development of the Silesian Unit). The concretions contain mainly siderite (Fe0.56-0.80 Ca0.03-0.07 Mg0.09-0.19 Mn0.01-0.06 CO3) and minor calcite. Accessory crystals and framboids of pyrite are common. Differences among samples are mainly in the grain size of carbonates and in variable proportion of siderite and calcite. Primary lamination composed of fine clastic grains is preserved within the calcite and/or siderite cement. The septaria cracks are filled with calcite and minor siderite.The carbonate concretions up to 1 m in diameter occur in the Cretaceous and Paleogene formations of the Silesian Unit in the Moravskoslezské Beskydy Mountains. Three concretions from three different formations were analyzed (Veřovice and Istebna formations and Albian-Cenomanian of the Kelč Development of the Silesian Unit). The concretions contain mainly siderite (Fe0.56-0.80 Ca0.03-0.07 Mg0.09-0.19 Mn0.01-0.06 CO3) and minor calcite. Accessory crystals and framboids of pyrite are common. Differences among samples are mainly in the grain size of carbonates and in variable proportion of siderite and calcite. Primary lamination composed of fine clastic grains is preserved within the calcite and/or siderite cement. The septaria cracks are filled with calcite and minor siderite