Cenozoic

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Main source = Baratov, R.B., et al. (1976). Subdivisions of stratified and intrusive rocks of Tajikistan. Publishing House "Donish", Dushanbe, 269 pp. plus tables. Provided by Dr. Jovid Aminov, Nazarbayev University, Astana, Kazakhstan Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

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Derbent Formation

Derbent Fm

Period:

Cretaceous

Age Interval:

Lower Albian (K₂¹), K1, S3, D1

Province:
SW Tajik, North Tajik

Type Locality and Naming

Includes in Khation Region, Darvaz District.

Upper substage of the Aptian stage and Albian stage in the Turkestan, Zarafshan-Gissar, South Gissar, Karategin, Dushanbe, Qafirnigan, Vakhsh, Zaalai and Darvaz districts includes five horizons: 1 – Karakuz (Upper Aptian - Lower Albian); 2 - Derbent (Lower Albian); 3 - Babatag (Middle Albian); 4 – Akkapchigay (Upper Albian); 5 - Shirabad (Upper Albian). Corresponding to these are variegated sandstones, argillites and clays containing layers of limestone, less often gypsum and conglomerates. Their total thickness is 100-800 m.

Synonym: Derbent horizon, Mingbatman suite, Mingbatman Fm

Lithology and Thickness

The Derbent horizon is represented by the Mingbatman suite (Shvanov, 1961), consisting of an interbedding of brown-red sandstones and clays 40-100 m thick. In districts 5,7,8 this horizon includes the entire suite, and in districts 6,9,11,12 - only the lower half of it.

Lithology Pattern:

Clayey sandstone

Relationships and Distribution

Lower contact

Overlies the Karakuz Fm.

Upper contact

Underlies the Babatag Fm.

Regional extent

Afghan-Tajik Basin.

GeoJSON

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Fossils

In the suite, shells of brackish and freshwater bivalves and ostracods Cardita minicostata Anupr., Cypridea sangardakens are known.

Age

Lower Albian

Age Span:

Beginning stage:

Albian

Fraction up in beginning stage:

0.10

Beginning date (Ma):

111.93

Ending stage:

Albian

Fraction up in the ending stage:

0.35

Ending date (Ma):

108.76

Depositional setting

Depositional pattern:

Additional Information

Compiler:

Chapman, J.B., et al. (9 co-authors), 2020. The Afghan-Tajik Basin: A composite record of sedimentary basin evolution in response to tectonics in the Pamir. Basin Research, 32(3), 525-545. https:/doi.org/10.1111/bre.12381.