Muborak Fm

Named by A.T. Tarasenko (Vlasov and Tarasenko, 1970), studied by E.N. Goretskaya (1961) and I.N. Cherenkov (1973), who consider it to be a flysch.

Synonym: Muborakskaya suite, Муборакская свита

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Composed of variously alternating dark gray claystones, polymict sandstones, siltstones (=silt like), and conglomerates, containing lenses of limestones. Thickness is 700-1100 m.

The Muborak Fm (Муборакская свита) is divided into two sub-suites. The lower sub-suite (400 m) is composed of rhythmically alternating sandstones, siltstones, claystones, limestones, and gravelites. On the lower sub-suite, with an erosion, the deposits of the upper sub-suite lie. It is also characterized by a rhythmic alternation of its constituent rocks (700 m), but unlike the lower sub-suite, it is coarser fragmental - sandstones, gravelites, and conglomerates interbed.

In the lower part of this sub-suite, in the valley of the Hanaka River, there are remains of foraminifera characteristic of the Lower Moscow sub-stage (not higher than the Kashirskaya horizon) Profusulinella rhomboides (Lee et Chen), Pr. ovata Raus., Lofusulina sp., Fusulinella sp., Aljutovella isvarica Putr. Together with them, shells of brachiopods characteristic of the Upper Moscow sub-stage have been found: Dictyoclostus uralicus Tchern., Marginifera cf. schelwieni Tchern., M. cf. kashirica Iv., M. cf. typica Waagen, M. confinus Einor, Neospirifer postriatus Nikif., Spirifer sorokini Rot., Sp. cameratus Mart., Linoproductus cora d'Orb., L. tenuistriatus Vern., Cancrinella cf. konincki Vern., Chonetes carboniferus Keyr., Productus cf, occidentalis Schellw., Choristites priscus Eichw., Echinoconchus fasciatus Kut., Enteletes cf. lamarkii Fisch., Derbia cf. grandis Waag., Echinoconchus punctatus Mart. In the upper parts of the sub-suite, remains of brachiopods Choristites fritschi var. ferganica Lich., Ch. cf. semichatovae Lich., Linoproductus simensis Tchern., L. villiersi d'Orb., Buxtonia subpunctatus (Nikif.), Martinia orientalis Tchern. and fusulinids Fusulinella bocki (Moell.), Triticites sp., Pseudofusulina sp., characteristic of the Upper Carboniferous, including its upper Dastarsky horizon, have been found.

N.G. Vlasov and A.T. Tarasenko (1970) suggest that the lower parts of the Muborakskaya suite (му6оракской свиты), containing Lower Moscow fusulinids, may partially belong to the Lower Moscow sub-stage.E. N. Goretskaya (1961) and I. N. Cherenkov (1973) consider the Lower Moscow foraminifera to be re-deposited. F. R. Bensh regards the lower sub-series of the Muborak suite (муборакской Свиты) as an analogue of the Sagdor suite of more western regions and assigns it to the Upper Bashkirian - Lower Moscow sub-stages, basing this solely on fusulinid determinations and assuming that brachiopods "overestimate the age" (1969, p. 74). F. R. Bensh considers the upper sub-series of the Muborak suite as an analogue of the Alyachapan suite (алячапанской свиты) of more western regions and assigns it to the lower half of the Upper Carboniferous. However, the complex of brachiopods, such as Choristites priscus Eichyr., Spirifer strangwaysi Vern., excludes the Bashkirian age of the lower sub-series. It is typical for the Moscow stage (Einor, Saltyovskaya, 1933). The question of the age of the Muborak suite requires further investigation.