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

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. [ABSTRACT FROM AUTHOR]