New data on the biostratigraphy and facies types of upper carboniferous Domanik sections in the Volga–Ural basin

From Clastics to Carbonates and Black Shales: Deciphering Sedimentary Continuity and Discontinuity in the Devonian Landscape of the Volga-Ural Petroleum Province

“…The designation of three predominant types of environments in the Middle-Late Devonian basin of the central part of the Volga-Urals Province: (1) condensed and non-condensed depressions, (2) slopes of depressions, and (3) shallow waters of tectonic arches (Aliev et al, 1978;Mkrtchyan, 1980) is supported by most contemporary researchers (Gatovsky et al, 2015;Fortunatova et al, 2016Fortunatova et al, , 2018Liang et al 2015Liang et al , 2020Stupakova et al, 2015Stupakova et al, , 2017Kabanov and Jiang, 2020;Kabanov et al, 2023a, b).…”

“…Many authors attribute the formation of sediments enriched in organic matter to the maximum level of basin flooding; and the formation of carbonate sediments, on the contrary, to basin regression (Stupakova et al, 2017;Chupakhina et al, 2022;Karpushin, Stupakova et al, 2022;Zavyalova, Karpushin, and Stupakova, 2023). Gatovsky et al (2015) considering Middle Frasnian organic rich black shales noted that these sediments are oversaturated with organic matter, and this circumstance could be the reason for the complete absence of the oxidative zone of diagenesis and the development of benthic anoxic conditions. The authors attribute the accumulation of organic rich sediments to the periods of high planktonic bioproductivity, which resulted in the accumulation of thin interlayers of horizontally laminated sapropelic muds.…”

Distinct features of crude oils from Nyurol’ka Depression (Southeast of Western Siberia)

“…Domanik horizon composed of dark gray, almost black limestones with a high bitumen content interbedded with the same color marl and clay siliceous shales and cherts (Gatovskii et al, 2016). The rock accumulation occurred in the epicontinental marine basin under normal salinity in warm humid climate.…”