Microfossils of the Southern Ural riphean stratotype and late precambrian of Eastern Siberia (paleobiologic aspects)

Stanevich, A. M.; Puchkov, V. N.; Корнилова, Т. А.; Сергеева, Н. Д.; Maksimova, E. N.

doi:10.31084/2619-0087/2018-3-1

Cited by 3 publications

(1 citation statement)

References 19 publications

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“…The Uk Formation includes stromatolites Linella ukka Krylov, Linella simica Krylov, Tungussia bassa Krylov, and Patomella kelleri Raaben (Krylov, 1967;Stratotip …, 1982). According to T. Jankauskas and A. Veis, microbiota in the Uk Formation is characterized by the abundant Leiosphaeridia, Protosphaeridium, and Siphonophycus typicum along with Palaeolyngbya zilimica, Bavlinella faveolata, and Symplassosphaeridium sp., as well as sheaths of Polytrichoides and Tortunema (Sergeev, 2006;Stanevich et al, 2018;Stratotip …, 1982;Veis et al, 2003). According to (Sergeev et al 2010), this microfossil assemblage is marked by low taxonomic diversity (relative to the Min'yar Formation) and wide stratigraphic distribution range.…”

Section: Introductionmentioning

confidence: 99%

Carbonate Sedimentology of the Upper Riphean (Neoproterozoic) Uk Formation, Southern Urals

Дуб

Гражданкин

2021

Lithol Miner Resour

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Lithological characteristics and results of the lithofacies analysis of carbonate deposits in the most complete section of the Upper Uk Subformation of the Riphean stratotype (northern part of the Bashkir Anticlinorium, southern Urals) are presented. The subformation is divided into the following members or sequences (from the bottom to top): Yuryuzan, Medved I, Manaysu, and Medved II. The subformation bottom occurs at the base of a huge stromatolite buildup. The Yuryuzan member is characterized by the thincolumnar branching stromatolites Patomella. The Medved I and Medved II members are represented mainly by bioherms consisting of the columnar-branching stromatolites Linella, interbiohermal rocks, and local packets of layered granular limestones found only in the lower member). The Manaysu member comprises layered (mainly cyclic) deposits with abundant molar tooth (MT) structures. The growth of the Yuryuzan member stromatolites occurred most likely in the upper subtidal-peritidal zone within the inner carbonate ramp under the influence of siliciclastic-bearing currents. Stromatolite buildups in Medved I and Medved II members were formed as a part of wide facies belts below the normal wave base (inner/middle ramp boundary) but within the photic zone. Layered limestones in the Medved I member are periodic storm current deposits. Environments of the inner ramp and upper middle ramp dominated during the deposition of Manaysu sediments with signatures of the influence of normal and storm waves. The sequence including the upper part of the Lower Uk Subformation, as well as the Yuryuzan and Medved I members of the Upper Uk Subformation, reflects a progressive deepening of the basin. The later slowdown in the rate of sea level rise (or fall) fostered the change in facies and the formation of the shallow-water Manaysu member. Subsequently, the transgressive trend appeared again, resulting in the formation of Medved II member. The upper boundary of the Uk Formation corresponds to a major break in the geological record associated with global glaciation.

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Section: Introductionmentioning

confidence: 99%

Carbonate Sedimentology of the Upper Riphean (Neoproterozoic) Uk Formation, Southern Urals

Дуб

Гражданкин

2021

Lithol Miner Resour

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Carbonate-siliciclastic deposits of the Lower Uk Subformation (Neoproterozoic) in the stratotype section and its correlation within Bashkirian Mega-Anticlinorium of the Southern Urals

Dub,

Melnichuk,

Krupenin

2024

Lithosphere

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Research subject. Carbonate-siliciclastic deposits of the Lower Uk Subformation were thoroughly studied in the section along the Yuryuzan river (near Ust-Katav town, Chelyabinsk region) and correlated with subformation sections along the Basu, Zilim and Bolshoy Inzer rivers. Material and methods. A detailed description of the stratotype section was carried out; sandstones, siltstones and limestones were studied in thin sections. The sections were correlated with each other. Results. Relationships between the Lower Uk Subformation and the underlying deposits are studied. The petrographic characteristics of rocks are presented. The Lower Uk Subformation sequences are traced between sections of various structural-tectonic zones of the Bashkirian Mega-anticlinorium (BMA). Conclusions. The set of features supports the idea about the presence of a sedimentary hiatus at the base of the formation, even in the most complete sequences (which contain the locally developed Shubino Member of the Minyar Formation). In the stratotype and in other reference sections, the Lower Uk Subformation has a pronounced three-membered structure; it is subdivided into the lower (siliciclastic) Yamashta, middle (substantially carbonate) Akkostyak, and upper (siliciclastic-carbonate) Avdyrdak members. The lithofacies analysis results suggest a change in environments from coastal-marine siliciclastic to shallow-marine siliciclastic-carbonate (middle and inner ramps) due to fluctuations in the relative sea level and, probably, climate change. It was established that the area of the Suleimanovo anticline at latest Riphean corresponded to the distal sedimentary environments in comparison with the southern and western zones (Alatau anticlinorium) of the BMA.

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Lithogeochemical characteristics and sedimentary environments of the Uk Formation limestones (upper Riphean, Southern Urals)

Maslov,

Dub

2024

Litologiâ i poleznye iskopaemye

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The lithogeochemical characteristics of the Uk Formation limestones (Uppermost Unit of the Riphean stratotype section in the Southern Urals) are considered. Data points of limestones (40 samples) accumulated in the middle and inner ramp environments have a quite contrasting distribution on diagrams with parameters (La/Sm)sh, (La/Yb)sh and (Sm/Yb)sh, proposed based on the systematization of a significant amount of analytical data on carbonate sequences formed in various platetectonic (in the broad sense of the word, paleogeographic) environments (according to [Zhang et al., 2017]) was established. The data points of the limestones of the Medved Member of the Uk Formation, which was formed, according to a detailed lithological-facies analysis, in the middle ramp environment, in the indicated diagrams located towards the field of limestones of the open ocean, while the limestones of the Manaysu Member (inner ramp deposits) in their geochemical characteristics are more consistent with the limestones of the near-coastal environments. Thus, the geochemical characteristics of the Uk Formation limestones seem to confirm the conclusions of the previous reconstructions. It has been suggested that in the example we described, the distribution of trace elements in the inner ramp limestones was apparently controlled by fine-grained siliciclastic material coming from the continent, while in the geochemical features of deeper-sea middle ramp limestones the influence of the open ocean environment is already perceptible.

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Microfossils of the Southern Ural riphean stratotype and late precambrian of Eastern Siberia (paleobiologic aspects)

Cited by 3 publications

References 19 publications

Carbonate Sedimentology of the Upper Riphean (Neoproterozoic) Uk Formation, Southern Urals

Carbonate Sedimentology of the Upper Riphean (Neoproterozoic) Uk Formation, Southern Urals

Carbonate-siliciclastic deposits of the Lower Uk Subformation (Neoproterozoic) in the stratotype section and its correlation within Bashkirian Mega-Anticlinorium of the Southern Urals

Lithogeochemical characteristics and sedimentary environments of the Uk Formation limestones (upper Riphean, Southern Urals)

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