Sedimentology and geochemistry of the Uk Formation, Upper Riphean, the Southern Urals
https://doi.org/10.24930/1681-9004-2019-19-5-659-686
Abstract
Research subject. This article presents new data on carbonate facies of the upperUk subformation, Upper Riphean of theSouth Urals. A particular attention is paid to the distribution of rare-earth elements (REE) and yttrium (Y) in stromatolitic and intraclastic limestones and calcareous shales (bulk samples and their acetic acid leachates).
Materials and methods. We have studied lithological features of limestones in the geological section and in thin sections. The contents of trace elements in rocks were determined by the ICP-MS method at the IGG UB RAS (Yekaterinburg), the composition of organic matter was determined at the IPGG SB RAS (Novosibirsk) by gas-liquid chromatography and chromatography-mass spectrometry.
Results. The most representative section of the Upper Uk Subformation located along the eastern edge of the town Ust-Katav can be subdivided into several members of different lithology and thickness: (1) biohermdominated member comprising large microbialitic build-ups and inter-bioherm sediments (intraclastic limestones, calcareous biolaminites); (2) transitional member characterised by small bioherms alternating with other carbonates; (3) interbedded coarseand fine-grained limestones. The presence of molar-tooth structures in the carbonate rocks of Uk Formation made it possible to constrain the age of thisUpper Riphean formation to pre-Cryogenian
Conclusions. There are similarities in REE and Y distribution in both clean (devoid of siliciclastic component) bulk limestone samples and in their acetic acid leachates. PAAS-normalised REE + Y patterns demonstrate positive La, Gd, Y anomalies and negative Eu, Ce anomalies. The latter suggest marine depositional environments for theUpper Uk stromatolitic limestones. The results of the pioneering research into the composition of bitumens and biomarkers from the Upper Uk Subformation have shown that carbonates and shales are depleted in the organic matter. The source material for the organic matter was provided by two types of communities comprising both eukaryotes and prokaryotes and inhabiting well aerated environment, perhaps with lowered salinity of marine water.
Keywords
About the Authors
A. V. MaslovRussian Federation
15 Vonsovsky st., Yekaterinburg, 620016
D. V. Grazhdankin
Russian Federation
3 Koptug av., Novosibirsk, 630090
S. A. Dub
Russian Federation
15 Vonsovsky st., Yekaterinburg, 620016
D. S. Melnik
Russian Federation
3 Koptug av., Novosibirsk, 630090;
1 Pirogova str., Novosibirsk, 630090
T. M. Parfenova
Russian Federation
3 Koptug av., Novosibirsk, 630090;
1 Pirogova str., Novosibirsk, 630090
A. V. Kolesnikov
Russian Federation
3 Koptug av., Novosibirsk, 630090
N. V. Cherednichenko
Russian Federation
15 Vonsovsky st., Yekaterinburg, 620016
D. V. Kiseleva
Russian Federation
15 Vonsovsky st., Yekaterinburg, 620016
References
1. Alexander B.W., Bau M., Andersson P., Dulski P. (2008) Continentally-derived solutes in shallow Archean seawater: rare earth element and Nd isotope evidence in iron formation from the 2.9 Ga Pongola Supergroup, South Africa. Geochim. Cosmochim. Acta, 72, 378-394.
2. Anderson K.D., Beauchamp B. (2014) Paleobiology and paleoecology of Palaeoaplysina and Eopalaeoaplysina new genus in Arctic Canada. J. Paleontol., 88(5), 1056-1071.
3. Bartley J.K., Kah L.C. (2004) Marine carbon reservoir, Corg–Ccarb coupling, and the Proterozoic carbon isotope record. Geology, 32, 129-132.
4. Bau M., Dulski P. (1996) Distribution of yttrium and rareearth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa. Prec. Res., 79(1-2), 37-55.
5. Bau M., Moller P. (1993) Rare earth element systematics of the chemically precipitated component in Early Precambrian iron formations and the evolution of the terrestrial atmosphere–hydrosphere–lithosphere system. Geochim. Cosmochim. Acta, 57, 2239-2249.
6. Becker Yu.R. (1961) Age and sequence of deposits in the upper part of the Karatau Group of the Southern Urals. Izv. Akad Nauk SSSR. Ser. Geol., (9), 49-60. (In Russian)
7. Becker Yu.R. (1958) On the stratigraphic position of Uk deposits in the Southern Urals. Dokl. Akad Nauk SSSR, 122(5), 879-882. (In Russian).
8. Bishop J.W., Sumner D.Y. (2006) Molar tooth structures of the Neoarchean Monteville Formation, Transvaal Supergroup, South Africa. I: Constraints on microcrystalline CaCO3 precipitation. Sedimentology, 53, 1049-1068.
9. Bolhar R., Kamber B.S., Moorbath S., Fedo C.M., Whitehouse M.J. (2004) Characterisation of Early Archaean chemical sediments by trace element signatures. Earth Planet. Sci. Lett., 222(1), 43-60.
10. Bolhar R., Van Kranendonk M.J. (2007) A non-marine depositional setting for the northern Fortescue Group, Pilbara Craton, inferred from trace element geochemistry of stromatolitic carbonates. Prec. Res., 155, 229-250.
11. Botting J.P., Muir L.A. (2017) Early sponge evolution: A review and phylogenetic framework. Palaeoworld, 27(1), 1-29.
12. Brocks J.J., Jarret A.J.M., Sirantoine E., Kenig F., Moczydlowska M., Porter S., Hope J. (2016) Early sponges and toxic protists: possible sources of cryostane, an age diagnostic biomarker antedating Sturtian Snowball Earth. Geobiology, 14, 129-149.
13. Burgsdorf I., Slaby B.M., Handley K.M., Haber M., Blom J., Marshal C.W., Gilbert J.A., Hentschel U., Steindler L. (2015) Lifestyle evolution in cyanobacterial symbionts of sponges. MBio, 6(3):e00391-15. doi:10.1128/mBio.00391-15.
14. Chen Y.J., Zhao Y.C. (1997) Geochemical characteristics and evolution of REE in the Early Precambrian sediments: evidences from the southern margin of the North China Craton. Episodes, 20, 109-116.
15. Clark J.P. Philp R.P. (1989) Geochemical characterization of evaporite and carbonate depositional environments and correlation of associated crude oils in the Black Creek Basin, Alberta. Can. Petrol. Geol. Bull., 37, 401-416.
16. Davies G.R., Nassichuk W.W. (1973) The Hydrozoan? Palaeoaplysina from the Upper Paleozoic of Ellesmere Island, Arctic Canada. J. Paleontol., 47 (2), 251-265.
17. De Baar H.J.W., Bacon M.P., Brewer P.G. (1985) Rare earth elements in the Pacific and Atlantic Oceans. Geochim. Cosmochim. Acta, 49, 1943-1959.
18. Domrachev S.M. (1952) Devonian of the Karatau Range and adjacent areas of the Southern Urals. Devonian of the West Ural. Leningrad; Moscow, Gostoptekhizdat Publ., Leningr. division, 5-121. (In Russian)
19. Dragastan O., Kube B., Richter D.K. (1999) New Late Triassic calcareous algae from Hydra, Greece. Acta Palaeontol. Rom., 2, 139-156.
20. Elderfield H. (1988) The oceanic chemistry of the rare-earth elements. Phil. Trans. Royal Soc. London, A325, 105-126.
21. Frei R., Dahl P.S., Duke E.F., Frei K.M., Hansen T.R., Frandsson M.M., Jensen L.A. (2008) Trace element and isotopic characterization of Neoarchean and Paleoproterozoic iron formations in the Black Hills (South Dakota, USA): assessment of chemical change during 2.9–1.9 Ga deposition bracketing the 2.4–2.2 Ga first rise of atmospheric oxygen. Prec. Res. 162, 441-474.
22. Frimmel H.E. (2009) Trace element distribution in Neoproterozoic carbonates as palaeoenvironmental indicator. Chem. Geol., 258, 338-353.
23. Ge L., Jiang S.-Y., Swennen R., Yang T., Yang J.-H., Wu N.-Y., Liu J., Chen D.-H. (2010) Chemical environment of cold seep carbonate formation on the northern continental slope of South China Sea: evidence from trace and rare earth element geochemistry. Mar. Geol., 277, 21-30.
24. Gold D.A., Grabenstatter J., Mendoza A., Riesgo A., RuizTrillo I., Summons R.E. (2016) Sterol and genomic analyses validate the sponge biomarker hypothesis. PNAS, 113(10), 2684-2689.
25. Gorozhanin V.M. (1995) Rb-Sr metod v reshenii problem geologii Yuzhnogo Urala. Diss. kand. geol-min nauk [Rb-Sr method in solving problems of the geology of the Southern Urals. Cand. geol. and min. sci. diss.] Ekaterinburg, IGG Ural Branch of RAS, 23 p. (In Russian)
26. Grazhdankin D.V., Maslov A.V. (2015) The room for the Vendian in the International Chronostratigraphic Scale. Russ. Geol. Geophys., 56, 549-559.
27. Grotzinger J.P., James N.P. (2000) Precambrian carbonates: evolution of understanding. Carbonate Sedimentation and Diagenesis in the Evolving Precambrian World. SEPM Spec. Publ., 67. Tulsa SEPM, 3-20.
28. Hill D. (1981) Rugosa and Tabulata. Treatise on Invertebrate Paleontology, Pt F. Teichert C. (Ed.), 762 p.
29. James N.P., Narbonne G.M., Sherman A.G. (1998) Molartooth carbonates: Shallow subtidal facies of the Midto Late Proterozoic. J. Sed. Res., 68, 716-722.
30. Kamber B.S., Webb G.E. (2001) The geochemistry of Late Archaean microbial carbonate: implications for ocean chemistry and continental erosion history. Geochim. Cosmochim. Acta, 65, 2509-2525.
31. Kozlov V.I. (1982) Verkhnii rifei i vend Yuzhnogo Urala [Upper Riphean and Vendian of the Southern Urals]. Moscow, Nauka Publ., 128 p. (In Russian)
32. Kozlov V.I. (1973) On the question of the structure of the Uk and Asha deposits of the Upper Proterozoic of the Southern Urals. Izv. Akad Nauk SSSR. Ser. Geol., (7), 112-123. (In Russian)
33. Kontorovich A.E. (1976) Geokhimicheskie metody colichestvennogo prognoza neftegazonosnosti [Geochemical methods for quantitative prediction of petroleum potential]. Moscow, Nedra Publ., 250 p. (In Russian)
34. Krylov I.N. (1963) Stolbchatye i vetvyashchiesya stromatolity rifeiskikh otlozhenii Yuzhogo Urala i ikh znachenie dlya stratigrafii verkhnego dokembriya [Columnar branching stromatolites of the Riphean deposits of the Southern Urals and their significance for Upper Precambrian stratigraphy]. Moscow, Nauka Publ., 243 p. (In Russian)
35. Krylov I.N. (1967) Rifeiskie i nizhnekembriiskie stromatolity Tyan’-Shanya i Karatau [Riphean and Lower Cambrian stromatolites from Tian Shan and Karatau]. Moscow, Nauka Publ., 78 p.
36. Krylov I.N. (1975) Stromatolity rifeya i fanerozoya SSSR [Riphean and Phanerozoic stromatolites from the USSR]. Moscow, Nauka Publ., 243 p. (In Russian)
37. Kuang H-W., Hu X.-F. (2014) Review of molar tooth structure research. J. Palaeogeography, 3, 359-383.
38. Kuznetsov A.B. (2013) Evolutsiya izotopnogo sostava strontsiya v proterozoiskom okeane. Diss. dokt. geolmin nauk [Evolution of strontium isotopic composition in the Proterozoic ocean. Dr. geol.and min. sci. diss.] St.Petersburg, IGGD RAN, 43 p. (In Russian)
39. Kuznetsov A.B., Bekker A., Ovchinnikova G.V., Gorokhov I.M., Vasilyeva I.M. (2017) Unradiogenic strontium and moderate-amplitude carbon isotope variations in early Tonian seawater after the assembly of Rodinia and before the Bitter Springs Excursion. Prec. Res. 298, 157-173.
40. Kuznetsov A.B., Gorokhov I.M., Mel’nikov N.N., Konstantinova G.V., Kutyavin E.P., Semikhatov M.A. (2003) Sr isotope composition in carbonates of the Karatau Group,the outhern Urals, and standard curve of 87Sr/86Sr variations in the Late Riphean Ocean. Stratigr. Geol. Correl., 11(5), 415-449.
41. Kuznetsov A.B., Gorokhov I.M., Semikhatov M.A., Kislova I.V., Maslov A.V., Krupenin M.T., Prasolov E.M. (2006) New data on Sr-and C-isotopic chemostratigraphy of the Upper Riphean type section (southern Urals). Stratigr. Geol. Correl., 14(6), 602-628.
42. Kuznetsov V.G. (2005) Molar tooth structure – is a specific structure of the Riphean sediments. Lithosfera, (4), 136-150. (In Russian)
43. Lee J.H., Byrne R.H. (1992) Complexation of trivalent rare earth elements (Ce, Eu, Gd, Tb, Yb) by carbonate ions. Geochim. Cosmochim. Acta, 57, 295-302.
44. Levashova N.M., Bazhenov M.L., Meert J.G., Kuznetsov N.B., Golovanova I.V., Danukalov K.N., Fedorova N.M. (2013) Paleogeography of Baltica in the Ediacaran: Paleomagnetic and geochronological data from the clastic Zigan Formation, South Urals. Prec. Res., 236, 16-30.
45. Love G.D., Grosjean E., Stalvies C., Fike D.A., Grotzinger J.P., Bradley A.S., Kelly A.E., Bhatia M., Meredith W., Snape C.E., Bowring S.A., Condon D.J., Summons R.E. (2009) Fossil steroids record the appearance of Demospongiae during the Cryogenian period. Nature, 457(7230), 718-721.
46. Luo C., Reitner J. (2014) First report of fossil “keratose” demosponges in Phanerozoic carbonates: preservation and 3-D reconstruction. Naturwissenschaften, 101, 467-477
47. Luo C., Reitner J. (2015) “Stromatolites” built by sponges and microbes – a new type of Phanerozoic bioconstruction. Lethaia, 49(4). 555-570.
48. Maslov A.V. (2004) Molar-tooth structures: evolution of views on the genesis. Karbonatnye i osadochnye posledovatel’nosti Urala i sopredel’nykh territorii: sedimentoi litogenez , minerageniya [Carbonate sedimentary sequences of the Urals and adjacent territories: sedimentoand lithogenesis, minerageny]. Ekaterinburg, IGG, Ural Branch of RAS, 98-101. (In Russian)
49. Maslov A.V., Meert J., Levashova N.M., Ronkin Yu.L., Grazhdankin D.V., Kuznetsov N.B., Krupenin M.T., Fedorova N.M., Ipat’eva I.S. (2013) New Constraints for the Age of Vendian Glacial Deposits (Central Urals). Doklady Earth Sciences, 449, 303-308.
50. McCaffrey M.A., Moldowan J.M., Lipton P.A., Summons R.E., Peters K.E., Jeganathan A., Watt D.S. (1994) Paleoenvironmental implications of novel C30 steranes in Precambrian to Cenozoic age petroleum and bitumen. Geochim. Cosmochim. Acta, 58, 529-532.
51. Moller P., Bau M. (1993) Rare-earth patterns with positive cerium anomaly in alkaline waters from Lake Van, Turkey. Earth Planet. Sci. Lett., 117(3–4), 671-676.
52. Nosenko T., Schreiber F., Adamska M., Adamski M., Eitel M., Hammel J., Maldonado M., Muller W.E.G., Nickel M., Schierwater B., Vacelet J., Wiens M., Worheide G. (2013) Deep metazoan phylogeny: When different genes tell different stories. Mol. Phylogen. Evol., 67, 223-233.
53. Nothdurft L.D., Webb G.E., Kamber B.S. (2004) Rare earth element geochemistry of Late Devonian reefal carbonates, Canning Basin, Western Australia: confirmation of a seawater REE proxy in ancient limestones. Geochim. Cosmochim. Acta, 68, 263-283.
54. Nozaki Y., Zhang J., Amakawa H. (1997) The fractionation between Y and Ho in the marine environment. Earth Planet. Sci. Lett., 148(1-2), 329-340.
55. Ovchinnikova G.V., Vasilyeva I.M., Semikhatov M.A., Kuznetsov A.B., Gorokhov I.M., Gorokhovskii B.M., Levskii L.K. (1998) U-Pb systematics of Proterozoic carbonate rocks: the Inzer Formation of the Upper Riphean stratotype (Southern Urals). Stratigr. Geol. Correl. 6, 336-347.
56. Ovchinnikova G.V., Vasilyeva I.M., Semikhatov M.A., Gorokhov I.M., Kuznetsov A.B., Gorokhovskii B.M., Levskii L.R. (2000) The Pb-Pb trail dating of carbonates with open U-Pb systems: the Myn’yar Formation of the Upper Riphean stratotype, Southern Urals. Stratigr. Geol. Correl., 8, 529-543.
57. Parekh P.P., Moller P., Dulski P., Bausch W.M. (1977) Distribution of trace elements between carbonate and noncarbonate phases of limestone. Earth Planet. Sci. Lett., 34, 39-50.
58. Parfenova T.M., Korovnikov I.V., Eder V.G., Melenevskii V.N. (2017) Organic geochemistry of the Lower Cambrian Sinyaya Formation (northern slope of the Aldan anteclise). Russ. Geol. Geophys., 58(5), 586-599.
59. Pawlowska M.M., Butterfild N.J., Brocks J.J. (2012) Lipid taphonomy in the Proterozoic and the effect of microbial mats on biomarker preservation. Geology, 41(2), 103-106.
60. Peters K.E., Moldowan J.M. (1993) The biomarker Guide: Interpreting molecular fossils in petroleum and ancient sediments. New Jersey: Prentis Hall, Englewood Cliffs, 363 с.
61. Petrov A.A. (1984) Uglevodorody nefti [Oil hydrocarbons]. Moscow, Nauka Publ., 264 p. (In Russian)
62. Petrov P.Y. (2016) Molar tooth structures and origin of peloids in Proterozoic carbonate platforms (Middle Riphean of the Turukhansk Uplift, Siberia). Lithol. Miner. Resour., 51(4), 290-309.
63. Pollock M.D., Kah L.C., Bartley J.K. (2006) Morphology of molar-tooth structures in Precambrian carbonates: Influence of substrate rheology and implications for genesis. J. Sed. Res., 76, 310-323.
64. Putevoditel’ geologicheskoi ekskursii po razrezam verkhnego paleozoya i verkhnego dokembriya zapadnogo sklona Yuzhnogo Urala i Priural’ya. [Guidebook of the geological excursion on the Paleozoic and Upper Precambrian sections of the western slope of the Southern Urals and Cis-Urals] (1995) Ufa, IG, Ufumian Scientific Centre of RAS, 176 p. (In Russian)
65. Raaben M.E., Zabrodin V.E. (1972) Vodoroslevaya problematika verkhnego rifeya (stromatolity, onkolity) [Upper Riphean algal problematic fossils (stromatolites, oncolites)]. Moscow, Nauka Publ., 130 p. (In Russian)
66. Riding R. (2004) Solenopora is a chaetetid sponge, not an alga. Palaeontology, 47(1), 117-122.
67. Semikhatov M.A., Chumakov N.M., Kuznetsov A.B. (2015) Isotope age of boundaries between the general stratigraphic subdivisions of the Upper Proterozoic (Riphean and Vendian) in Russia: The evolution of opinions and the current estimate. Stratigr. Geol. Correl., 23(6), 568-579.
68. Shaw H.F., Wasserburg G.J. (1985) Sm-Nd in marine carbonates and phosphates: Implications for Nd isotopes in seawater and crustal ages. Geochim. Cosmochim. Acta, 49, 503-518.
69. Shields G.A. (2002) ”Molar-tooth microspar”: a chemical explanation for its disappearance ~750 Ma. Terra Nova, 14(2), 108-113.
70. Shields G.A., Webb G.E. (2004) Has the REE composition of seawater changed over geological time? Chem. Geol., 204, 103-107.
71. Shields-Zhou G.A., Hill A.C., Macgabhann B.A. (2012) The Cryogenian Period. A Concise Geologic Time Scale / J.G. Ogg, G.M. Ogg, F.M. Gradstein (Eds). Amsterdam, Elsevier, 393-411.
72. Sholkovitz E.R., Landing W.M., Lewis B.L. (1994) Ocean particle chemistry – the fractionation of rare-earth elements between suspended particles and seawater. Geochim. Cosmochim. Acta, 58(6), 1567-1579.
73. Sinninghe Damsté J.S., van Duin A.C.T., Hollander D., Kohnen M.E.L., de Leeuw J.W. (1995) Early diagenesis of bacteriohopanepolyol derives: Formation of fossil homohopanoids. Geochim. Cosmochim. Acta, 59, 5141-5147.
74. Smith A.G. (2016) A review of molar-tooth structures with some speculations on their origin. Belt Basin: Window to Mesoproterozoic Earth / MacLean J.S., Sears J.W. (Eds). Geol. Soc. Am. Spec. Paper, 522, 71-99.
75. Stratotip rifeya. Paleontologiya. Paleomagnetizm. [Stratotype of the Riphean: Paleontology and Paleomagnetism] (1982). (Keller B.M. Ed.). Moscow, Nauka Publ., 176 p. (In Russian)
76. Stratotip rifeya. Stratigrafiya. Geokhronologiya [Stratotype of the Riphean: Stratigraphy and Geochronology] (1983). (Eds: Keller B.M., Chumakov N.M.). Moscow, Nauka Publ., 184 p. (In Russian)
77. Tang H.-S., Chen Y.-J., Santosh M., Zhong H., Yang T. (2013) REE geochemistry of carbonates from the Guanmenshan Formation, Liaohe Group, NE Sino-Korean Craton: Implications for seawater compositional change during the Great Oxidation Event. Prec. Res., 227, 316-336.
78. Taylor M.W., Radax R., Steger D., Wagner M. (2007) Sponge-associated microorganisms: evolution, ecology, and biotechnological potential. Microbiol. Mol. Biol. Rev., 71, 295-347.
79. Taylor S.R., McLennan S.M. (1985) The Continental Crust: Its Composition and Evolution. Oxford, Blackwell, 312 p.
80. Terakado Y., Masuda A. (1988) The coprecipitation of rare-earth elements with calcite and aragonite. Chem. Geol., 69, 103-110.
81. Van Kranendonk M.J., Webb G.E., Kamber B.S. (2003) New geological and trace element evidence from 3.45 Ga stromatolitic carbonates in the Pilbara Craton: support of a marine, biogenic origin and for a reducing Archaean ocean. Geobiology, 1, 91-108.
82. Vassoevich N.B. (1973) The main laws that characterize the organic matter of modern and fossil sediments. Priroda organicheskogo veshchestva sovremennykh i iskopaemykh osadkov [The nature of the organic matter of modern and fossil sediments]. Moscow, Nauka Publ., 11-59. (In Russian)
83. Webb G.E., Kamber B.S. (2000) Rare earth elements in Holocene reefal microbialites: a new shallow seawater proxy. Geochim. Cosmochim. Acta, 64, 1557-1565. Wilkinson C.R. (1979) Nutrient translocation from symbiotic cyanobacteria to coral reef sponges. Biologie des Spongiarires, 291. (Lévi C., Boury-Esnault N. Eds). Colloques du Centre National Reserche Scientifique, Paris: 373-380.
84. Wright J., Schrader H., Holser W.T. (1987) Paleoredox variations in ancient oceans recorded by rare earth elements in fossil Apatite. Geochim. Cosmochim. Acta, 51, 631-644.
85. Zaitseva T.S., Gorokhov I.M., Kuznetsov A.B., Mel’nikov N.N., Yakovleva O.V., Ivanovskaya T.A., Semikhatov M.A., Arakelyants M.M. (2008) Mössbauer characteristics, mineralogy and isotopic age (Rb-Sr, K-Ar) of Upper Riphean glauconites from the UK Formation, the southern Urals. Stratigr. Geol. Correl., 16(3), 227-247.
86. Zaitseva T.S., Gorokhov I.M., Kuznetsov A.B., Konstantinova G.V., Turchenko T.L., Melnikov N.N. (2012) Rb-Sr isotopic systematics of clay minerals from sedimentary rocks of the Vendian of the Southern Urals. Leningrad School of Lithology. V. II. St. Petersburg, SPbSU Publ., 57-59. (In Russian)
87. Zhong S., Mucci A. (1995) Partitioning of rare earth elements (REEs) between calcite and seawater solutions at 25°C and 1 atm, and high dissolved REE concentrations. Geochim. Cosmochim. Acta, 59, 443-453.
Review
For citations:
Maslov A.V., Grazhdankin D.V., Dub S.A., Melnik D.S., Parfenova T.M., Kolesnikov A.V., Cherednichenko N.V., Kiseleva D.V. Sedimentology and geochemistry of the Uk Formation, Upper Riphean, the Southern Urals. LITHOSPHERE (Russia). 2019;19(5):659-686. (In Russ.) https://doi.org/10.24930/1681-9004-2019-19-5-659-686