The composition and formation conditions of the Upper Lochkovian Valgan Formation (Lower Devonian Ilych River, Northern Urals)
https://doi.org/10.24930/1681-9004-2020-20-1-63-75
Abstract
Research subject. A section of the Upper Lochkovian (Lower Devonian) Valgan Formation located in the stratotypic area on the Ilych River, Northern Urals, was investigated.
Materials and methods. A study of the composition and structure of rock samples gathered from the section under consideration during fieldwork in 2015 was conducted.
Results. The studied section with an exposed thickness of 51 m is characterized by the thin and uneven alterations of calcareous con-glogravelites, coarse-grained and fine-grained organic sandsones, bioclatic-pelitomorphic limestones and argillo-calcareous shales. These rocks demonstrate a gradational and convolute lamination. An individual interval of the studied section contains calcareous conglobreccias layers. The Valgan Formation is characterized by a cyclic structure, with the thickness of individual cyclites ranging from 5.0 to 25 cm. The character of their structure testifies to sedimentation in slope settings. An analysis of clastic material revealed two sources of the basin area formation: near ablation (represented by the fragments of background bioclastic-pelitomorphic limestones) and remote ablation (represented by biohermal rock clasts). It is proposed to consider the Valgan Formation as the Valgan gradation, which extends the Upper Lochkovian sulfate-carbonate Subformation to the east.
Conclusions. Therefore, the Valgan gradation should be treated as an intermediate link between shallow-marine Upper Lochkovian biohermal structures and bathyal clayey and siliceous shales.
Supporting agencies: The author expresses his sincere gratitude to A.I. Antoshkina, V.A. Saldin, and E.S. Shcherbakov for their discussions, comments and recommendations concerning the work on this article. The work was carried out in the framework of the state Program No. AAAA-A17-117121270034-3 and at partial financial support of the fundamental research Program UB RAS, project No. 18-5-5-31
About the Author
E. S. Ponomarenko
N.P. Yushkin Institute of Geology Komi Science Center, RAS
Russian Federation
Russian Federation
Evgenii S. Ponomarenko
54 Pervomayskaya st, Syktyvkar 167982
References
1. Antoshkina A.I. (1992) Features of structure Lower Paleozoic reefogenic stratum of the Northern Urals. Prirodnye reservuary Pechorskogo neftegazonosnogo basseina [Natural reservoirs of the Pechora oil and gas basin]. Syktyvkar, IG KSC UB AN SSSR, 5-21. (In Russian)
2. Antoshkina A.I. (1994) Rify v paleozoe Pechorskogo urala [Reefs in the Paleozoic at the Pechorian Urals]. St.Petersburg, Nauka Publ., 154 p. (In Russian)
3. Antoshkina A.I. (2006) Rifoobrazovanie v paleozoe (sever urala i sopredel ’nye oblasti) [Reef formation in the Paleozoic (northern part of the Urals and adjacent areas]. Ekaterinburg, UrO RAN, 303 p. (In Russian)
4. Antoshkina A.I. (2006) Spacetime links in structure Lower Paleozoic Kaleidovaya Formation at the north of Urals]. Problemy geologii i mineralogii [The problrms of Geology and Mineralogy] (Otv. red. A.M. Pystin). Syktyvkar, Geoprint Publ., 351-364. (In Russian)
5. Bouma A.H. (1962) Sedimentology of some flysch deposits. Amsterdam, Elsevier, 168 p.
6. Coniglio M., Dix G.R. (1992) Carbonate slopes. Facies models response to sea level change (Eds. R.G. Walker and N.P. James), 349-373.
7. Eliseev A.I. (1978) Formatsii zon ogranicheniya severo-vostoka Evropeiskoi platformy (pozdnii devon i carbon) [Formations of bordering zones of the European platform (Late Devonian and Carboniferous)]. Leningrad, Nauka Publ., 203 p. (In Russian)
8. Eliseev A.I. (1982) Sravnitel’nyi formatsionnyi analiz ogranichenii platform v paleozoe [The comparative for-mational analysis of platform bordering into Paleozoic]. Nauchnye doklady. Tr. KF AN SSSR, 78. Syktyvkar, 56 p. (In Russian)
9. Eliseev A.I., Antoshkina A.I., Saldin V.A., Nikulova N.Yu., Kozyreva I.V., Sandula A.N. (2006) Formatsii paleozoya severo-vostocnoi okrainy Evropeiskoi platformy [Paleozoic Formations of the north-east margin of the European platform]. Nauchnye doklady Tr. KNTs UrO RAN, 481, Syktyvkar, 72 p. (In Russian)
10. Flugel E. (2004) Microfacies of carbonate rocks: analysis, interpretation and application. Berlin Heidelberg Springer-Verlag, 976 p.
11. Obstanovki osadkonakopleniya i fatsii. T. 2 [A sedimentation environments and facies. V. 2]. (1990) Moscow, Mir Publ., 384 p. (In Russian)
12. Pershina A.I., Tsyganko V.S., Shcherbakov E.S., Borintse-va N.A. (1971) Biostratigrafiya siluriiskikh i devonskikh otlozhenii Pechorskogo urala [Biostratigraphy of Silurian and Devonian deposits of the Pechorian Urals]. Leningrad, Nauka Publ., 129 p. (In Russian).
13. Ponomarenko E.S. (2018) Structure of Upper Lochkovian (Lower Devonian) Lop’yu Kyrta organic buildup (Ilych River, Northern Urals)]. Vestn. IG Komi NTs urO RAN, (6), 35-42. (In Russian)
14. Puchkov V.N. (1979) Batial’nye complexy passivnykh kontinental’nykh okrain geosinklinal’nykh oblastei [Bathial complexes of passive continental margins of geosynkline areas]. Moscow, Nauka, 258 p. (In Russian)
15. Stratigraficheskie skhemy urala (dokembriya, paleozoya) [Stratigraphic schemes of the Urals (Precambrian, Paleozoic)]. (1993) (Red. N.Ja. Antsygin, B.A. Popov, B.I. Chu-vashov). Ekaterinburg, IGG Ur O RAN, Roskomnedra Publ., 151 sh. (In Russian)
16. Tsyganko V.S. (2011) Devon zapadnogo sklona severa urala i Pay-Khoya (stratigrafiya, printsipy raschleneni-ya, korrelatsiya) [Devonian of the western slope of the Northern Urals and Pay-Khoy (stratigraphy, separation principles, correlation)]. Ekaterinburg, UrO RAN, 356 p. (In Russian)
17. Varsanof’eva V. A. (1940) Geologic construction of Pechora-Ilych national reserve. Tr. Pechoro-Ilychskogo zapoved-nika, 1, 1-214. (In Russian)
18. Voinovskii-Kriger K.G. (1945) Dva kompleksa paleozoya na zapadnom sklone Pripolyarnogo Urala [Two Paleozoic complexes on the Western slope of the Subpolar Urals]. Sov. geologiya, (6), 27-45. (In Russian)
19. Walker R.G. (1992) Turbidites and Submarine Fans. Facies models response to sea level change (Eds. R.G. Walker and N.P. James), 239-264.
20. Wilson J.L. (1975) Carbonate facies in geologic history. N.Y., Springer, 471 p.
21. Yudin V.V. (1983) Varistsidy Severnogo urala [Variscides of the Northern Urals]. Leningrad, Nauka Publ., 173 p. (In Russian)
22. Yudovich Ya.E., Maidl’ T.V., Ivanova T.I. (1980) Geokhim-iya strontsiya v karbonatnykh otlozheniyakh (v svya-zi s problemoi geokhimicheskoi diagnostiki rifov) [The strontium geochemistry in carbonate deposits (in connection with geochemical diagnostics of reefs)]. Leningrad, Nauka Publ., 152 p. (In Russian)
Review
For citations:
Ponomarenko E.S. The composition and formation conditions of the Upper Lochkovian Valgan Formation (Lower Devonian Ilych River, Northern Urals). LITHOSPHERE (Russia). 2020;20(1):63-75. (In Russ.) https://doi.org/10.24930/1681-9004-2020-20-1-63-75
Views:
537
Email this article 