Geologicheskii Vestnik

In 2018, the Usolka section received the GSSP (Global Stratotype Section and Point) status of the lower boundary of the Sakmarian Stage of the Permian system of the International Stratigraphic Scale. This section is also the object for study of boundaries of Kasimovian and Gzhelian stages of the Carboniferous system. Species marking the lower boundaries of the Kasimovian and Gzhelian stages are considered: Swadelina subexcelsa (Alekseev et Goreva) and Streptognathodus simulator Ellison. For the fi rst time, radiolarian ecozones (Haplodiacantus circinatus – Albaillella protractosegmentata, Astroentactinia luxuria – Triactofenestrella nicolica and Entactinia austrouralica – Polyentactinia multifora) were distinguished at the Kasimovian and Gzhelian boundary. High potential of the section as a standard for stage boundaries of the Upper Carboniferous of International Stratigraphic scale is revealed.

“Usolka” section, Carboniferous, Kasimovian Stage, Gzhelian Stage, conodonts, radiolarians, GSSP

• Aleksees А.S., Goreva N.V. Conodonty pogranichnogo intervala moskovskogo i kasimovskogo yarusov (carbon) na Yuzhnom Urale [Conodonts of the Moscowian/Kasimovian boundary interval (Carboniferous) of the South Urals] // Trudy XV Vserossiiskogo mikropaleontologicheskogo soveshchaniya “Sovremennaya micropaleontologiya”. Gelendzhik, 2012. P. 189–193. (In Russian with English abstract).
• Afanasieva М.S., Amon E.О., Chuvashov B.I. Radiolarii v biosratigraphii i paleogeographii carbona Prikaspiya i Yuzhnogo Predural′ya [Radiolarians in Carboniferous Stratigraphy and Paleobiogeography in Eastern Europe (Precaspian and Southern Cis-Urals)] // Lithosphere. 2002. No. 4. P. 22–62. (In Russian).
• Chernykh V.V. Opredelenie yarusnykh granits Mezhdunarodnoi stratigrafi cheskoi shkaly po conodontam [The determination of the stage boundaries of the International Stratigraphic Scale by conodonts] // Lithosphere. 2008. No. 1. P. 3–17. (In Russian).
• Chernykh V.V., Chuvashov B.I., Davydov V.I., Henderson C.M., Shen S., Schmitz M.D., Sungatullina G.M., Sungatullin R.Kh., Barrick J.E., Shilovsky O.P. Southern Urals. Deep water successions of the Carboniferous and Permian // A Field Guidebook of 18th International Congress on Carboniferous and Permian. Pre-Congress A3 Trip. Kazan: Academy of Sciences of the Republic of Tatarstan Press, 2015. 88 p.
• Chernykh V.V., Chuvashov B.I., Davydov V.I., Schmitz M., Snyder W.S. Usolka section (Southern Urals, Russia): a potential candidate for GSSP to defi ne the base of the Gzhelian Stage in the global chronostratigraphic scale // Geologija. 2006. No. 49. P. 205–217.
• Chuvashov B.I., Chernykh V.V. Razrez “Krasnousolskii” // Putevoditel′ geologicheskih ekskursii po karbonu Urala. // Yekaterinburg, IGG UB RAS, 2002. Part 1: South Ural tour. P. 18–33. (In Russian).
• Chernykh V.V., Chuvashov B.I., Shen S.Z., Henderson C.M. Proposal for the Global Stratotype Section and Point (GSSP) for the base-Sakmarian Stage (Lower Permian) // Permophiles. 2016. Vol. 63. P. 4–18.
• Chuvashov B.I., Mizens G.A., Dyupina G.V., Chernykh V.V. Opornye razrezy verkhnego karbona i nizhnei permi tsentral′noi chasti Bel′skoi vpadiny [Key-sections of the Upper Carboniferous and Lower Permian central part of the Belsk depression]. Sverdlovsk: USC AS USSR, 1983. 56 p. (In Russian).
• Davydov V.I., Wardlaw B.R. Progress on the Cisuralian (Lower Permian) timescale, Southern Urals, Russia // Permophiles. 2005. Vol. 45. P. 9–11.
• Davydov V.I., Leven E.Y., Chuvashov B.I. Fusulinid Biostratigraphy in Asselian – Sakmarian transition in stratotype area Southern Urals, Russia // Permophiles. 1999. Vol. 35. P. 30–31.
• Kotlyar G.V. Globalnyi stratotipicheskii razrez i tochka (GSSP) nizhnei granitsy sakmarskogo yarusa priural′skogo otdela permskoi sistemy (Yuzhnyi Ural, Rossia) [Global Stratotype Section and Point (GSSP) for the lower boundary of the Sakmarian Stage of the Cisuralian, the Permian (South Urals, Russia)] // Regionalnaya geologiya i metallogeniya. 2019. No. 77. P. 6–10. (In Russian).
• Schmitz M.D., Davydov V.I. Quantitative radiometric and biostratigraphic calibration of the Pennsylvanian – Early Permian (Cisuralian) time scale and pan-Euramerican chronostratigraphic correlation // Geological Society of America Bulletin. 2012. Vol. 124. P. 549–577.
• Sungatullina G.M., Davydov V.I. New data on conodonts from the Kasimovian Stage of the Usolka section, southern Ural Mountains // Paleontological Journal. 2015. Vol. 49, Is. 10. P. 1142–1149.
• Sungatullina G.M., Davydov V.I., Barrick J.E., Sungatullin R.Kh. Conodonts of Kasimovian-Gzhelian transition, Usolka section, Southern Urals, Russia: New data // Newsletter on Carboniferous Stratigraphy. 2016. Vol. 32. P. 54–57.
• Sungatullina G., Sungatullin R., Shilovsky O., Statsenco E., Aysina R., Karimullina I. Kasimovian Conodonts and Ammonoids of the Usolka Section (Southern Urals) // A Proceedings Kazan Golovkinsky Stratigraphic Meeting “Advances in Devonian, Carboniferous and Permian Research: Stratigraphy, Environments, Climate and Resources”. Bologna: Filodiritto Publisher, 2018. P. 230–238.