Publication details
Pestré sedimenty ottnangu v Brně-Kohoutovicích
| Title in English | Ottnangian variegated sediments in Brno-Kohoutovice |
|---|---|
| Authors | |
| Year of publication | 2018 |
| Type | Article in Periodical |
| Magazine / Source | Geologické výzkumy na Moravě a ve Slezsku |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.5817/GVMS2018-1-2-73 |
| Keywords | Ottnangian-Carpathian Foredeep-petrography- X-ray diff raction analysis (XRD analysis)- whole rock geochemistry- Foraminifera- palaeogeography-heavy minerals |
| Description | The reddish coloured sediment layers (up to 5 m thick) were found within building pit in the Brno-Kohoutovice on the Libuše Avenue(NW part of Brno). These sediments were assigned to the Ottnangian sediments based on characteristic pseudoassociation of microfossils.Smectite or illite/smectite dominates over kaolinite among the clay minerals. Minerals typomorphic for granitoids of the BrnoMassif, i.e. epidote, amphibole and altered titanite, absolutely dominate (99 mod. percent) within the assemblage of translucent heavyfraction. Minerals like garnet and staurolite which are typical for the Ottnangian sediments in this region, are presented only inaccessoric amount. The chemical composition of the studied sediments is located between the chemical composition of granodioritesof the Brno Massif and Neogene clays. Relatively high content of Zr, Hf and HREE, which is interpreted as result of presence of veryfinegrained zircon in studied sediments, is characteristic. High content of SiO2 and comparatively low contents of Al2O3 and Fe2O3indicates non-lateritic type of weathering. The chemical composition of studied sediments reflects semiarid to humid paleoclimatethat the granitoids of the Brno Massif as parent rock have undergone. |