Geologicheskii Vestnik

Ordovician conodonts from the Arvyak Formation in the Southern Urals have been obtained for the first time. The conodonts are represented by Periodon aff. aculeatus Hadding, Staufferella? sp. and two conical elements. A scolecodont was found together with the conodonts. The Arvyak formation is part of the metamorphic Suvanyak complex of Uraltau zone and is dated to the Early Ordovician. The Arvyak Formation of the Uraltau zone is compared by authors with the Bakty Formation of the Yuryuzan structure and the Tirlyan-Kaginskaya strata of the West Zilair zone, which formed in the Ordovician in shallow-water shelf conditions along the eastern framing of the Bashkir anticlinorium. Biostratigraphic confirmation of the Ordovician age of the conglomerates and sandstones of the Arvyak Formation indicates a connection between part of the Ordovician deposits of the Uraltau zone and the eastern framing of the Bashkir anticlinorium. The Ordovician deposits of the Uraltau zone are facies represented by shallow-water shelf and deep-water deposits of the continental slope. The finding of conodonts in the deposits of the Arvyak formation allows us to change its age to Middle-Upper Ordovician and consider it an analogue of the Baktin formation and the Tirlyan-Kagin strata.

conodonts, Ordovician, sedimentary environments, Souvanyak complex, Uraltau, Southern Urals

• Klochikhin A.V. (1960) Ordovik, silur i nizhnii devon vostochnogo sklona Zilairskogo sinklinoriya na Yuzhnom Urale [Ordovician, Silurian and Lower Devonian of the eastern slope of the Zilair synclinorium in the Southern Urals]. Voprosy geologii vostochnoi okrainy Russkoi platformy i Yuzhnogo Urala. Vyp. 7. Ufa, BFAN SSSR. P. 33–36. (In Russian).
• Knyazev Yu.G. (2006) Stratifikatsiya razrezov suvanyakskogo kompleksa antiklinoriya Uraltau [Stratification of sections of the Suvanyak complex of the Uraltau anticlinorium]. Geologiya, poleznye iskopaemye i problemy geoekologii Bashkortostana, Urala i sopredel’nykh territorii: Materialy VI Mezhregional’noi nauchno-prakticheskoi konferentsii. Ufa: DizainPoligrafServis. P. 57–59. (In Russian).
• Knyazev Yu.G., Knyazeva O.Yu., Karimov T.R. (2008) Gosudarstvennaya geologicheskaya karta Rossiiskoi Federatsii. Masshtab 1:200 000. Izdanie vtoroe. Seriya YuzhnoUral’skaya. List N-40-XXVIII. Ob”yasnitel’naya zapiska. M.: MF VSEGEI [State Geological Map of the Russian Federation. Scale 1:200,000. Second edition. South Ural Series. Sheet N-40-XXVIII. Explanatory note]. 251 p. (In Russian).
• Knyazev Yu.G., Knyazeva O.Yu., Karimov T.R. (2015) Gosudarstvennaya geologicheskaya karta Rossiiskoi Federatsii. Masshtab 1:200 000. Izdanie vtoroe. Seriya Yuzhno-Ural’skaya. List N-40-XXIII (Beloretsk). Ob”yasnitel’naya zapiska [State Geological Map of the Russian Federation. Scale 1:200,000. Second edition. South Ural Series. List N-40-XXIII (Beloretsk). Explanatory Note]. SPb.: Kartograficheskaya fabrika VSEGEI. 237 p. (In Russian).
• Krauze S.N., Maslov V.A. (1961) Ordovik, silur i nizhnii devon zapadnogo sklona Bashkirskogo Urala [Ordovician, Silurian and Lower Devonian of the Western Slope of the Bashkir Urals]. Ufa: BFAN SSSR. 96 p. (In Russian).
• Krinitskii D.D., Krinitskaya V.M. (1965) Ob otkrytii na yuge Bashkirii siluriiskikh otlozhenii sredi drevnikh tolshch zapadnogo sklona khrebta Ural-Tau [On the discovery of Silurian deposits in the south of Bashkiria among ancient strata of the western slope of the Ural-Tau ridge]. Materialy
  po geologii i poleznym iskopaemym Yuzhnogo Urala. M., Nedra. 4, 37–39. (In Russian).
• Mavrinskaya T.M., Yakupov R.R. (2009) O vozraste suvanyakskogo kompleksa zony Uraltau [On the age of the Suvanyak complex of the Uraltau zone]. Geologicheskii sbornik. IG UNTs RAN. Ufa. 8, 15–16. (In Russian).
• Mavrinskaya T. M., Yak upov R. R. (2016) Biostratigraficheskaya kharakteristika suvanyakskogo i maksyutovskogo kompleksov Uraltau (Yuzhnyi Ural) [Biostratigraphic characteristics of the Suvanyak and Maksyutovsky complexes of the Uraltau (Southern Urals)]. Geologiya, poleznye iskopaemye i problemy geoekologii Bashkortostana, Urala i sopredel’nykh territorii. Materialy XI Mezhregional’noj nauchno-prakticheskoj konferencii. Ufa: IG UNTs RAN. Ufa. 11, 53–55. (In Russian).
• Moseichuk V.M., Yarkova A.V., Shalaginov A.E., Kollegov A.K., Kashina L.V., Ryabukhina M.Yu., Sapel’tseva Yu.A. (2010) Gosudarstvennaya geologicheskaya karta Rossiiskoi Federatsii m-ba 1:200 000. Izdanie vtoroe [State Geological Map of the Russian Federation, scale 1:200,000. Second edition]. Red.V. N. Puchkov. List N-40 XVII (Tirlyanskii). Ob”yasnitel’naya zapiska. SPb.: Kartograficheskaya fabrika VSEGEI. 337 p. (In Russian).
• Ozhiganov D.G. (1955) Geologicheskoe stroenie metamorficheskogo poyasa khrebta Ural-Tau Yuzhnogo Urala [Geological structure of the metamorphic belt of the Ural-Tau ridge of the Southern Urals]. Uchenye zap. Bash. pedinstituta. 4, 3–54. (In Russian).
• Olli V.A., Chibrikova E.V. (2004) Organicheskie ostatki iz metamorficheskogo kompleksa khrebta Ural-Tau (novye nakhodki na Yuzhnom Urale) [Organic remains from the metamorphic complex of the Ural-Tau ridge (new finds in the Southern Urals)]. Geologicheskii sbornik. Ufa: IG UNTs
  RAN. 4, 77–81. (In Russian).
• Rodionov V.Yu., Radchenko V.V. (1988) O stratigrafii paleozoiskikh otlozhenii vostochnogo kryla Zilairskogo megasinklinoriya [On the stratigraphy of Paleozoic deposits of the eastern wing of the Zilair megasynclinorium]. Biostratigrafiya devona i karbona Urala. Ufa. BNTs UrO AN SSSR. P. 15–23. (In Russian).
• Yakupov R.R. (2007) Problematichnye organicheskie ostatki iz utkal’skoi svity suvanyakskogo kompleksa Uraltau [Problematic organic remains from the Utkal suite of the Suvanyak complex of the Uraltau]. Geologicheskii sbornik. Ufa: IG UNTs RAN. 6, 4–6. (In Russian).
• Yakupov R.R. (2008) Khitinozoi iz metamorficheskikh kompleksov Uraltau (Yuzhnyi Ural) [Chitinozoa from metamorphic complexes of the Uraltau (Southern Urals)]. Novosti paleontologii i stratigrafii. 49 (10–11), 184–186. (Pril. k zhurn. «Geologiya i geofizika»). (In Russian).
• Yakupov R.R. (2024) Ordovikskie ikhnofossilii zapadnogo sklona Yuzhnogo Urala [Ordovician ichnofossils of the western slope of the Southern Urals]. Geologicheskii vestnik. 2, 3–20. DOI: 10.31084/2619–0087/2024-2-1 (in Russian).