Ichnological aspect of fossiliferous nodules of the Šárka Formation (Ordovician, Llanvirnian, Czech Republic)


Authors: Mikuláš R

Published in: Bulletin of Geosciences, volume 78, issue 1; pages: 83 - 88; Received 25 June 2001; Accepted in revised form 22 November 2002;

Keywords: Ordovician, Llanvirnian, Prague Basin, ichnofossils, nodules, diagenesis,

full text (PDF, 0.35 MB)

Export to RIS



In the muddy, oxygen-deficient sediments of the Llanvirnian of the Prague Basin, chemical disequilibrium between burrows and the host substrate were a common reason for the origin of nodules. As the ichnofossils are well preserved in the nodules, without deformation, the origin of the nodules during very early diagenesis is likely, in some cases possibly contemporaneous with the existence of the open burrow. The steepest chemical gradient can be expected close to the openings of the burrows. Therefore, these parts of burrows may have had the highest fossilization potential. The ichnogenera of Skolithos, Planolites, Rhizocorallium and Glockerichnus were recognized as possible agents of the nodule-forming process.