ASGP (2012), vol. 82: 331–347

MICROBIAL LAMINITES WITH COPROLITES FROM UPPER JURASSIC CARBONATE BUILDUPS (KRAKÓW-CZĘSTOCHOWA UPLAND, POLAND)

Alicja KOCHMAN & Jacek MATYSZKIEWICZ

Faculty of Geology, Geophysics and Environment Protection, AGH University of Science and Technology, Al. Mickiewicza 30; 30-059 Kraków, Poland; e-mails: kochman at geol.agh.edu.pl, jamat at geol.agh.edu.pl

Kochman, A. & Matyszkiewicz, J., 2012. Microbial laminites with coprolites from Upper Jurassic carbonate buildups (Kraków-Częstochowa Upland, Poland). Annales Societatis Geologorum Poloniae, 82: 331–347.

Abstract: The Upper Oxfordian microbial-sponge agglutinated to open-frame reef complex of the Zegarowe Crags in the Kraków-Częstochowa Upland originated upon an elevation of the Late Jurassic stable northern shelf of the Tethys. This elevation was formed, owing to a local decrease in subsidence rate during Jurassic time, induced by the presence of a Palaeozoic granitoid intrusion in the shelf substratum, and Late Jurassic, synsedimentary tectonics, which controlled the topography of the sea bottom. The Zegarowe Crags (Skały Zegarowe) complex at the top contains microbial laminites, composed of peloidal and agglutinated stromatolites, and intercalations of grainstones with indeterminable, favrenoid coprolites, occurring in large numbers. The development of stromatolites was associated with low nutrient availability. In contrast, the periodic activity of crabs, the main producers of the coprolites, forming the coprolitic grainstone intercalations, indicates periods, when nutrients were abundant in the sea water. The nutrinets most likely were associated with the occurrence of clouds of suspended matter, induced by gravity flows, generated by active, synsedimentary tectonics. The results of isotopic studies do not support the presence of warm, mineralizing solutions, connected with synsedimentary tectonics during development of the Zegarowe Crags complex in the Late Jurassic.

Manuscript received 25 October 2012, accepted 20 December 2012