Abstract
A working group of the International Subcommittee on Carboniferous Stratigraphy is working to determine the boundary of the Vise and Serpukhov stages. Comprehensive work was carried out with the aim of biostratigraphic substantiation of the most important boundaries of the Lower Carboniferous, including such priority boundaries as: Vise and Serpukhov, as well as studying the horizons of Vise and Serpukhov by conodonts, ammonoids and comparing them with foraminifera scales for international correlation of Kazakhstani divisions. The upper boundary of the Visean stage is adopted in the parastratotype in France. The border has not been studied enough. One of the best sections of the boundary deposits of the Vise and Serpukhov stages in Kazakhstan is the Beleuta section of the Zhezkazgan-Chu district. Geologists have been interested in Zhezkazgan-Chu district since the 18th century. One of the most studied sections is located on the Beleuty River near the confluence of the Sholaksai River in Zhezkazgan district in the Sholak mulda, it was described in the middle reaches of the Beleuta River on the right bank. The article presents the results of field paleontological and biostratigraphic work carried out in the Ulutau region (Central Kazakhstan). The purpose of these field works was to study the sections of the boundary sediments of the Vise and Serpukhov stages of the Lower carboniferous in order to clarify the correlation of regional stratigraphic units with units of the international stratigraphic scale, to substantiate the lower boundary of the Serpukhov carboniferous stage according to orthostratigraphic groups of fauna using modern methods. To achieve this goal, stratotypic sections were discovered and identified, their coordinates were established, boundary sediment layers were measured and described, lithological and paleontological work was carried out (including samples for fauna), spectrometric gamma-ray logging was carried out, organic remains, including foraminifera, were identified and described.