Foraminifers and Biostratigraphy of the Upper Visean–Serpukhovian Boundary Beds of the Novogurovsky Quarry (Tula Region, Russia)

Foraminifera from the Serpukhovian section (Lower Carboniferous) of the Novogurovsky quarry (southern wing of the Moscow Basin, type area of the Serpukhovian Stage) are studied. The foraminiferal assemblages from the boundary deposits of the Visean and Serpukhovian stages (Eostaffella tenebrosa–Endothyranopsis sphaerica and Neoarchaediscus postrugosus zones) are described in detail. The boundary marker is the species Janischewskina delicata (Malakhova, 1956), additional markers are Neoarchaediscus regularis (Suleimanov, 1948), Pseudoendothyra illustria ovata Reitlinger, 1963 and P. illustria grandis Reitlinger, 1963. Four microfacies were identified in the carbonate deposits of the Visean-Serpukhovian boundary interval.