Biogenic ultramicrostructures in riphean stromatolites in the Volga-Uralian area (East Russian plate)

Abstract

Abstract: The article presents the results of a study of core samples, including stromatolite dolomites of the Kaltasa (Lower Riphean) and Leuza (Upper Riphean) formations of the Volga-Uralian area of Russia. Using a scanning electron microscope, fossilized remains of coccoid and filamentous microfossils, as well as fragments of bacterial biofilms accompanying them, were found in stromatolites. The nature of biogenic ultramicrostructures is confirmed by the determination of the elemental composition. Fossilized relics of organisms are characterized by the presence of biophilic elements and increased carbon content compared to the rocks that include them.