Ayakuduk Formation

Ayakuduk Fm

Period:

Devonian

Age Interval:

Eifelian-Givetian, K8

Province:
Kyzylkum Region

Type Locality and Naming

Along the Ayaakuduk section, Arianstatau Mountains, Central Kyzylkum. N.M. Larin, N.V. Cherkashenko, 1989 (495, p. 42). Stratotype in the central part of the Arianstatau Mountains. Uppermost formation in East Aristanau Reef Fm

Synonym: Ayakkuduk Suite, Аякудукская св.

Lithology and Thickness

Limestones and dolomites, interbedded with algal limestones and rare layers of dolomitic breccias. In the middle and upper parts of the section, organogenic structures are developed, composed of light-gray massive limestones with remains of corals and algae. Thickness 230-369m.

Lithology Pattern:

Dolomitic limestone

Relationships and Distribution

Lower contact

It normally overlies the Iza Fm

Upper contact

It is conformably overlain by the Beshashik Fm (165; 495).

Regional extent

Central Kyzylkum, central part of the Arianstatau Mountains. The Ayakuduk Fm is an age equivalent of the Auliekudzhumdin Fm in Muruntau.

GeoJSON

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Fossils

Contains stromatoporoids - Stromatopora hupschii Bargat., Stachyodes gracilis kuznetskensis Yavor., Amphipora aff. ramosa Phill.; corals - Scoliopora ex gr. Denticulata M.E. et H., Caliopora ex gr. battersbyi M.E. et H.; brachiopods - Chonetes ex gr. nana Vern., Productella mesodevonica Nal., Kransia parallelepipeda (Bronn.) of Givetian age; Tentaculites - Nowakia otomari Bouček. et Prantl., Viriatellina ex gr. irregularis Bouček; conodonts - Polygnathus costatus costatus Klap., P. costatus oblongus Wedd. and others

Age

Fossil data correspond to the interval from the australis zone to the lower varcus, i.e., from the middle of the Eifelian to the lower part of the Givetian.

Age Span:

Beginning stage:

Eifelian

Fraction up in beginning stage:

0.75

Beginning date (Ma):

387.55

Ending stage:

Givetian

Fraction up in the ending stage:

0.25

Ending date (Ma):

383.70

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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