Carboniferous fauna from erratics in the Hradyzk area (Poltava region, Ukraine): paleo-ice streams indicator of the Dnipro glacial maximum

ABSTRACT

Several hundred fragments of limestone and cherts with debris of various macrofauna have been found in the glacial sediments among crystalline Precambrian erratics along the left bank of the Kremenchuk reservoir. The collection includes a variety of corals, chaetetids, brachiopods, orthoceratids, crinoids and other forms. In many cases, it was possible to identify species of the corals, chaetetids and brachiopods. The identified species showed its Carboniferous age. The stratigraphic distribution is limited to a rather narrow range spanning the time interval from the Upper Viséan to Serpukhovian. An overview of the outcrops where these rocks are now exposed indicates that the most likely source of the Carboniferous erratic pebbles and boulders is in the southern and western flanks of the Moscow Syneclise where fossil-rich Carboniferous rocks are exposed at the upper reaches of the Volga and Oka rivers. The configuration of the southern boundary of the Dnipro glacier indicates changes in its path from S to SW. This could have happened due to impingement of the glacier against the Central Russian Upland. The finding of a significant amount of Carboniferous erratics in glacial sediments of the southeastern part of the Dnipro lobe near the town of Hradyzk supports this conclusion.

KEYWORDS:

• Dnipro glaciations
• glacial till
• Lower Carboniferous erratics
• indicator fossils
• ice-flow directions

Acknowledgments

I am very grateful to I. Chernikov who first discovered and collected Carboniferous faunas from the erratics in the Hradyzk area. Part of this collection was transferred to the Taras Shevchenko National University of Kyiv for detailed study. Thanks are also extended to M. Lishenko (Kremenchuk) for having found and transferred to us fauna from the Quaternary deposits near the Kremenchuk town. I wish to thank V. Poletaev (Kyiv) for the identification of brachiopod species. My thanks are extended to two anonymous reviewers whose constructive comments have significantly improved this paper. I am also truly thankful to Dr S.H. Stevens (San José State University, California, U.S.A.) for English corrections. This investigation is performed according to the research program No. 16КP049-08 (Institute of Geology, Taras Shevchenko National University of Kyiv). The paper is a contribution to INQUA-HABCOM [Project 1606].

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the INQUA-HABCOM [Project 1606].