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Main source = Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian) Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

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Akbulak-Ord Formation

Akbulak-Ord Fm


Period: 
Ordovician

Age Interval: 
Lower-middle Ordovician, N5a


Province: 
Nuratau

Type Locality and Naming

Along the Akbulaksai River, Malyuzar Mountains. M.P. Pulatov, I.N. Elizov in 1970-1972 in the volume of the conditional upper Cambrian (72, p.79).

Synonym: Akbulakskaya Svita, Акбулакская св.


Lithology and Thickness

At the base of the section are argillaceous shales, carbonaceous shales, and carbonaceous-siliceous gray and dark-gray shales with interlayers and lenses of platy limestones, siltstones, and more rarely sandstones. Thickness: 80 m.

The upper part consists of gray and light-gray thin-bedded shales interbedded with platy siliceous shales of greenish-gray color. Thickness: 20 m.


Lithology Pattern: 
Claystone


Relationships and Distribution

Lower contact

Contacts are tectonic.

Upper contact

Contacts are tectonic.

Regional extent

Malgyzhar Mountains, headwaters of the Khojamushkent, Akbulaksay, and Taubulaksay rivers, within tectonic blocks. It is an analog of the Dzhalatar Fm of the North Nuratau Range.


GeoJSON

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Fossils

At the base – Contains conodonts of the Early–Middle Ordovician — Drepanodus proteus Lind., D. Flabellum Knüp., D. altipes Henn., and others.

The upper part – They contain conodonts of the Middle Ordovician — Cordylodus ramosus Hadd., Acontiodus cooperi Sweet and Berg., Scolopodus insculptus (Branson and Mehl), and others.


Age 

Assigned to the Lower–Middle Ordovician (72; 165).

Age Span: 

    Beginning stage: 
Dapingian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
471.26

    Ending stage: 
Dapingian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
469.42

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

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