Elemesachi Formation

Elemesachi Fm

Period:

Carboniferous

Age Interval:

Moscovian, K5

Province:
Kyzylkum Region

Type Locality and Naming

Along the Elemesachi, N. Tamdytau, Central Kyzylkumy. Sh. Sh. Sabdyushev et al., 1969 (393, pp. 6-10), in the volume of early-middle Cambrian. Stratotype locality - eastern part of Northern Tamdytau, area of the village of Elemesachi., south of Balyktau and along the Dzheroyzay.

Synonym: Elemesachi Suite, Елемесачинская св.

Lithology and Thickness

Coarse clastic tuffs and xenotuffs of trachybasalts, basalts, and andesibasalts; lavas of this composition have limited distribution. Subvolcanic dikes of trachytes and rhyolites, explosion pipes, composed of clastolavas and lava breccias of trachybasalts and basalts, are rarely observed. In tuffs and lavas, boulders and blocks (olistoliths?) of limestones (thickness from 0.2-0.5 to 100 m) are often found. Sandstones, shales, black cherts, plagiogranites, and basalts. Thickness 500-600m (Bukharin et al., 1990, Mikhailov et al., 1988).

Lithology Pattern:

Volcanic_ash

Relationships and Distribution

Lower contact

According to some researchers, reliable stratigraphic contacts have not been established (Abduazimova et al., 1993), while others believe that the Elemesachi Fm overlies the Tayman Fm, Akkuduk Fm, and Ayakum Fm

Upper contact

It is overlain by Cretaceous deposits (Bukharin et al., 1990).

Regional extent

Central Kyzylkum, Northern Tamdytau.

GeoJSON

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Fossils

Contains early Cambrian trilobites - Parapoliella kysylcumica Hajr., Neopagetina cf. rjansnitzkii (Lerm.), Ushbaspis grata Hajr., etc.; archaeocyaths - Tegerocyathus edelsteini (Vol.), T. abacanensis (Vol.), Flindersicyathus kuzmini (Vol.), etc., stenotekoids - Cambridium asiaticum Kon., C. clishevichi Kon., Stenotecoides Dubius Kon., etc.; algae - Epiphytou scapulum Korde, E. celsum Korde, Renalcis polymorphys (Masl.), etc.; middle Cambrian trilobites Peronopsis Fallax Lin., Glabrella babacovia Rep., Kooteniella Modesta Hajr., etc.; late Cambrian trilobites - Pseudagnostus impressus Lerm., P. quadrata Pokr., P. prolongus Pokr., etc. (Abduazimova et al., 1996).

Age

The age of the Elemesachi Fm is debatable. I.A. Poniklensky et al. (1975), Sh.Sh. Sabdyushev et al. (393), based on collections of organic remains from limestone, chert, and shale blocks, date it to the Cambrian, Z.M. Abduazimova et al. (1993) - to the Cambro-Ordovician. Other researchers believe that this fauna is reworked and assign the suite either an early-middle Carboniferous age (Pyatkov et al., 1975) or a middle Carboniferous age (Mikhailov et al., 1988, Bukharin et al., 1990). On the State Geological Map-500 of Uzbekistan (460), it is dated to the Moscovian Stage of the Middle Carboniferous. The age of the Ellemesachi Fm as the Moscovian Stage of the Middle Carboniferous is established based on its correlation with formations of similar composition (Tubabergen Fm, Shavaz Fm, etc.) and its stratigraphic position.

Age Span:

Beginning stage:

Moscovian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

315.15

Ending stage:

Moscovian

Fraction up in the ending stage:

0.5

Ending date (Ma):

311.09

Depositional setting

Depositional pattern:

Additional Information

Compiler:

V.V. Mikhailov – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”