Irlik Formation

Irlik Fm

Period:

Devonian

Age Interval:

Lower-Middle Devonian, K2

Province:
Kyzylkum Region

Type Locality and Naming

Along the city of Irli, Bukantau Mountains, Central Kyzylkum. Ya. B. Aysanov et al., 1980.

Synonym:

Lithology and Thickness

Rhythmically interbedded medium-bedded, gray, dark-gray dolomites, red-colored clayey limestones with lenses and layers of quartzitic siliceous rocks; at the base, a basal layer of polymictic, siliceous-quartz, and carbonate gravels, sandstones, and marls (Telibay and Yerambetza areas); in other places, the basal layers are cut by faults. Thickness 260-350m.

Lithology Pattern:

Dolomitic limestone

Relationships and Distribution

Lower contact

Relationships with older strata are everywhere tectonic (Aysanov et al., 1984). The suite lies with erosion, angular, and azimuthal unconformity and a basal package at the base on the Lyupek Fm, Telibay Fm, and Bzdontau Fm.

Upper contact

Overlain by the Dzhetyimtau Fm (Jetymtau suite) (460). According to A.K. Bukharin et al. (1990).

Regional extent

Central Kyzylkum, in the form of a continuous sublatitudinal strip on the southern slope of the Irli carbonate ridge of the Bukantau Mountains.

GeoJSON

null

Fossils

Contains stromatoporoids - Paramphipora sp. (ex gr. gracilisporis Less.), Amphipora sp., Stachyodes sp., etc.; conodonts - Eognathodus sp. ind.; brachiopods Conchidiella mirabilis Rzon., Carinatina aff. arimaspus (Eichw.), Atrypa cf. olgae Nal., etc.

Age

The Early-Middle Devonian age is established by organic remains. (460).

Age Span:

Beginning stage:

Lochkovian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

419.00

Ending stage:

Eifelian

Fraction up in the ending stage:

1.0

Ending date (Ma):

385.30

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)”