New data on red Visean calcareous algae of the Dnipro-Donetsk Depression: systematic composition and facial confinement


 As a result of the study core material 540 thin sections from boreholes northern marginal part and paraxial Dnieper-Donetsk Depression (DDD), complex fossil red calcareous algae including 14 species 7 genera, as well 2 belonging to genera identified for first time Visean deposits DDD has been discovered. The studied carbonate represent Hlybokynskyi, Sukhynskyi, Stylskyi, Donetskyi lower Mezhivskyi horizons Don-Dnipro Rift (DDR). It found that greatest diversity taxonomic composition in is observed Stylskyi most horizons, (XIII, XIIa, XII microfaunistic DDD). established limestones zone dated uppermost (XI MFH DDD) are represented mainly by foraminiferous-polydetrital algal wackestones, less often wacke-packstones. association with dark ferruginous fragments indicatesthat formed relatively deep conditions outer shelf. Carbonate sediments (XIIa, polydetrital sometimes they spicular, iron-bearing, which makes it possible assume these deposits, like previous ones, belong deep-water facies open platform, moderate reduced water circulation. Sukhynskyi lowermost (XIII rift side zones fine-detrital-algal wackestones remains ostracods, mosses, spicules, brachiopod shells, Stacheaceae, green tubular family Palaeoberesellaceae Mamet et Roux. predominance siphonocladal indicates calm hydrodynamic regime below tide level depth basin, mostly does not exceed 3-5 m, small fluctuation sea good illumination, thermal conductivity basin. Hlybokynskyi horizon (XIV exposed 10 Skorobahatky DDD, organogenic, detritus-muddy packstones bivalves, foraminifera, crinoids, green, Roux transition upper sandy grainstone. This were shallow under constant wave action, near base this action led washout clay mass.