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Arankazgan Formation

Arankazgan Fm


Period: 
Devonian

Age Interval: 
Eifelian-Givetian, K9


Province: 
Kyzylkum Region

Type Locality and Naming

Along Arapkazgan, Kuldzhuktau Mountains, Central Kyzylkum. Ya.B. Aysanov, A.I. Egorov, 1978 (44, pp. 35-37), the name was given in 1984 (1984f.).

Synonym: Arapkazganskaya Suite, Аранказганская св., Arap-Kazgan Fm


Lithology and Thickness

The most complete section is in the area of the Isokuduk, where it is represented by siliceous-quartz jasper-like rocks with layers and lenses of black limestones and pinkish-gray weakly calcareous slates. Thickness 150m.


Lithology Pattern: 
Chert


Relationships and Distribution

Lower contact

Relationships with underlying formations are traced south of Sultanbibi, Aktasty, Shaidaraz, Isokuduk, where they, according to A.A., transgressively overlie the limestones of the Sultanbibi Fm. In other places, the relationships with ancient rocks are tectonic.

Upper contact

The upper boundary is not established (tectonic). (165; 460). Schematic stratigraphic column indicates the upper contact as Shaidaraz Fm

Regional extent

Central Kyzylkum, in the form of separate areas and narrow strips south of the Isokuduk, Turkmenkazgan, Sultanbibi, Aktasty, Shaidaraz, as well as north of the Uchkuduk, southeast of the Bashguzhumdy, northeast of the Tozbulak massif, and in the area of the Koshshashak heights.


GeoJSON

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Fossils

Contains tabulates - Chaetetes">Chaetetes cf. salairicus Dubat., C. cf. ninae Tchern., Caliopora cf. graciosa Yanet.; stromatoporoids - Amphipora cf. ramosa Phill., Stachyodes cf. gracilis kuznetskensis Yavor., S. sp. (ex gr. singularis Yavor.); rugose Zonophyllum sp. (ex gr. duplicatus Wdkd.), Bethanyphyllum sp., Grypophyllum sp.; brachiopods - Stringocephalus sp., characterizing the Middle Devonian Eifelian and Givetian age of the deposits.


Age 


Age Span: 

    Beginning stage: 
Eifelian

    Fraction up in beginning stage: 
0.5

    Beginning date (Ma): 
389.80

    Ending stage: 
Givetian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
378.90

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

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