Acta Musei Moraviae

Petrography and chemical composition of mudstones and marls of the Silesian Unit (Godula facies; Western Carpathians)

This paper is focused on the chemical composition of mudstones and marls from the Godula facies of the Silesian Unit of Moravian-Silesian Carpathians (Godula, Istebna, Rožnov, Menilite and Krosno formations). The chemical composition of sediments, lithology and fossil record reflect maximum depths during deposition of the Godula, Istebna and lower part of Rožnov formations. Up the sequence, general shallowing trend influenced the deposition. The differences in chemical composition reflect changes in the source of clastic material and/or environment of sedimentation. Chemical composition of pelitic rocks from Godula and Istebna formations indicates sedimentation bellow the CCD and higher contribution of clastic material. Based on the concentration of Cu, Zn, Ni, Co, and Cr, we supposed that the conditions fluctuated from oxic to dysoxic during the deposition of Istebna, Rožnov, and Krosno formations. Most of the pelitic rocks of the Menilite Formation were deposited in anoxic environment.