Facies diversity of the Brno Jurassic from microfacies and microfauna point of viewArticle PDF
Facies diversity of the Brno Jurassic from microfacies and microfauna point of view
Denudation remnants of Upper Jurassic carbonates in Brno area were originally part of vast carbonate platform on the eastern margin of the Bohemian Massif. High facies variability reflects original variable mosaic of shallow marine habitats. The prevailing microfacies type are biopelmicritic spiculites (packstones) with enclaves of biomicrite, intrabiomicrite and pelmicrite (packstones and wackestones). Locally bed of crinoidal biosparitic limestone (encrinite) and oosparitic limestone occurs. Microfaunal associations were studies in acid residues of limestone. Calcareous benthic foraminifera, sponge spicules and echinoderm ossicles prevail over other groups (bryozoans, bivalves, ostracods, brachiopods, stromatoporoids etc.). Comparative analysis of the microfacies from thin sections and quantitative analysis of microfauna from acid residues was applied for identification of original locality of pliosaur tooth from the collections of the Masaryk University, Brno, lacking the original lable. Combined microfacial features and characteristic composition of microfossil assemblage from the limestone enclosing the tooth show that the find very probably came from lower part of Stránská skála section.
Miroslav Bubík, Czech Geological Survey, Leitnerova 22, 658 69 Brno, Czech Republic; e-mail: firstname.lastname@example.org