Turkestan Formation

Turkestan Fm

Period:

Paleogene

Age Interval:

Middle Eocene (Lutetian–Bartonian), F2

Province:
Fergana

Type Locality and Naming

Along Turkestan. O.S. Vyalov, 1935 (155, p. 280). Stratotype in the area of the city of Isfara, Fergana Depression. Middle formation in Turkestan Horizon Gr. In Fergana, the lower part of the suite was previously distinguished as the Yarkutan Horizon (160; 215; 223; 444).

Synonym: Turkestanskaya Formation, Туркестанская св.

Reference section:

Lithology and Thickness

Tobacco-green, greenish-gray clays, siltstone (aleuritic) with layers of marls, in South Fergana - limestones (city "m"). According to K.P. Kalitsky) (213), in the pre-Tashkent region - bentonites, gravelites. Thickness up to 246m.

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

Along the position, it lies on the Alay Fm and Akkum Fm, with erosion on various horizons of the Upper Cretaceous or on the Paleozoic (Angren Plateau)

Upper contact

Overlain by the Rishtan Fm and Apata Fm or with erosion by the Tashsai Fm (Lower Miocene).

Regional extent

Fergana Depression, Pre-Tashkent region, South-West Gissar.

GeoJSON

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Fossils

Contains marine bivalve mollusks - Pectunculus aralensis Rom., Fatina esterhazyi Pav., Lucina consobrina Desh., L. menardi Desh., Cardium porulosum Desh., Pitar gumberensis Arch.; foraminifera - Gaudryina superturkestanica N. Byk., Discorbis ferganensis N. Byk., Rotalia alaica N. Byk., radiolarians - Cenodiscus planus Moks., Spongodiscus ammophus Moks., Cenosphaera kizilkumensis Lipm., ostracods; spores and pollen.

In the lower part of the suite, shells of Ostrea turkestanensis Rom. and shells transitional from Turkostrea to Fatina (transitional layers) are found.

Age

Belongs to the Middle Eocene, Lutetian stage (upper part) in the span of the Acarinina rotundimarginata Subb. zone and Bartonian (lower part) in the span of the Hantkenina alabatensis and Globigerina turkmenica zones (without the upper part).

Age Span:

Beginning stage:

Lutetian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

44.55

Ending stage:

Bartonian

Fraction up in the ending stage:

0.1

Ending date (Ma):

40.70

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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