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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Lower Sumasar Formation

Lower Sumasar Fm

Period:

Silurian

Age Interval:

Llandovery-Wenlock (S₁), C1a

Province:
Central W Tajik

Type Locality and Naming

In the Agbashir type, to which the section at the mouth of the Agbashir River (basin of the Saraymat River) in Tajikistan, and the sections in the interfluve of the Karasu-Zhandarya in the neighboring territory of Uzbekistan belong, lower Silurian deposits are represented (Lavrushevich et al., 1962; Kim, 1966) by the Lower Sumasar. This suite name was proposed in 1966 by A. I. Kim. Z. Z. Mufthiev et al. (1971) call it the South Sumasar suite.

Synonym: South Sumasar suite

Reference section:

Lithology and Thickness

(up to 250 m thick) suite of medium and fine-bedded dark gray to black dolomites and dolomitic limestones, containing subordinate interlayers of sandy (quartz) limestones and quartz sandstones.

Lithology Pattern:

Dolomitic limestone

Relationships and Distribution

Lower contact

Upper contact

Regional extent

GeoJSON

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Fossils

In the Lower Sumasar Fm deposits, tabulate corals Palaeofavosites alveolaris (Goldf.), Catenipora gotlandica (Yabe), C. cf. escharoides Lam.; rugose corals Ketophylloides cf. atlassovi Tschern.; brachiopods Virgiana ex gr. barrandei Billings, Pentamerus ex. gr. oblongus Sow. and others have been found.

Age

Llandovery-Wenlock

Age Span:

Beginning stage:

Rhuddanian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

443.07

Ending stage:

Homerian

Fraction up in the ending stage:

1.0

Ending date (Ma):

426.74

Depositional setting

Depositional pattern:

Additional Information

Compiler:

Extracted from Baratov, R. B. (1976). Subdivisions of stratified and intrusive rocks of Tajikistan. Donish, Dushanbe, 276.