Graptolite assemblages and stratigraphy of the lower Silurian Mrákotín Formation, Hlinsko Zone, NE interior of the Bohemian Massif (Czech Republic)
Abstract
Fourteen of the graptolite biozones, previously recognised in the Llandovery succession of the Barrandian area of central Bohemia, have been identified in the heavily tectonized and poorly exposed, epizonal and contact metamorphic black slates and silicites of the Mrákotín Formation of the Hlinsko Zone. Graptolites were collected by bulk sampling of loose boulders.
The sedimentary succession of the Mrákotín Formation has been reconstructed, in particular by detailed correlation with the biostratigraphically well dated, graptolite-rich successions in the Barrandian area and Thuringia. 112 graptolite species have been recorded, Pseudorthograptus finneyi sp. nov. was described. There is little difference between the graptolite faunas of the Hlinsko Zone and the Barrandian area, but the lithological successions of the two areas differ.
Mrákotín Formation was deposited near the depositional site of the coeval formations of Saxo-Thuringia and West Sudetes, rather than near the Barrandian area.