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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Chapsay Formation

Chapsay Fm

Period:

Permian

Age Interval:

Changhsingian (P₂ p), D1

Province:
SW Tajik

Type Locality and Naming

The Chapsayskaya suite was established in 1955 by N. G. Vlasov (1961).

Synonym: Chapsayskaya suite, Чапсайская свита, Pamir Horizon, Chapsai suite, чапсайской свиты

Reference section:

Lithology and Thickness

This suite belongs to the Pamir horizon. It is made up of gray-violet and green-gray medium and fine-grained sandstones in its lower and middle parts, containing rare layers and lenses of calcareous tuffs, siltstones, algal limestones, and porphyrites are present. In the upper part, dark gray algal limestones are present, occasionally containing interlayers of gray and yellow clays. The thickness of the suite is 1000 m. The thickness of the limestones in the upper part of the suite varies from 440 to 70 m, which is explained by partial facies replacements by underlying terrigenous rocks. To some extent, the limestones lying on the Chapsai suite, in places with weak angular discordance, could have been eroded before the formation of the red sandstones of the Vasmikukh Fm of the Induan stage.

Lithology Pattern:

Fine-grained sandstone

Relationships and Distribution

Lower contact

The nature of the contact between the Chapsay Fm (чапсайской свиты) and the older Shakarsev Fm is unclear. Most likely, it is conformable. However, this conclusion is based on the assumption that belonging to the belong to the Chapsai suite are several-meter-thick algal limestones lying conformable on the gypsum-bearing sediments of the Shakarsev Fm on the right bank of the river Obi-Ravno and not containing already the layers of gypsum characteristic of the Shakarsev Fm. If these limestones are attributed to the Shakarsev Fm, which is possible in principle, but is associated with changes in the perception of its volume, then the nature of the boundary between the Chapsay and Shakarsev Fm will remain unclear. Similar contacts are probably present in the valley of the Chapsay (Obiravnoouskoy) river.

Upper contact

Regional extent

They are widespread in the Darvaz region within the Southwestern Darvaz.

GeoJSON

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Fossils

Chapsay suite (чапсайской свиты) (belongs to the Pamir horizon, which is determined by collections of foraminifera remnants Glomospira sp., Nodosaria aff. permiana (Spandel), N. aff. krotowi Tscherd., Pachyphloia ovata Lange, P. cf. multiseptata Lange, Parapa. chyphloia sp., Geinitzina spandeli Tscherd., Spandellina sp., etc. in its upper part limestones. In these same limestones, Permian algae Vermiporella sp., Gymnocodium ex gr. bellerophontis Retpl., Permocalculus sp., as well as Permian bryozoans Tabulipora sp., Pinnatopora sp., Fenestella sp., Lioclema sp., and pelecypods similar to lower Triassic, Eumorphothis cf. bocharica (Bittn.), E. cf. multiformis (Bittn.), Anadonthophora cf. fassaensis Wissm. (Vlasov and Miklukho-Maklai, 1959; Vlasov, 1961) were found.

Age

V.I. Popov (1933) considered the terrigenous lower and middle parts of the Chapsay suite as a separate upper Permian "upper gray tuffaceous" suite, and the upper part of the Chapsay suite as "bryozoan limestones", attributed to the lower Triassic. Similar views were held by G.A. Dutkevich and M.A. Kalmykova (1937), as well as M.A. Kalmykova (1959), who proposed the name of the Kafarmol "series" or "thickness" for terrigenous rocks. G.A. Dutkevich and M.A. Kalmykova suggested that the upper "bryozoan" limestones lie on underlying deposits with angular discordance.

Age Span:

Beginning stage:

Changhsingian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

254.24

Ending stage:

Changhsingian

Fraction up in the ending stage:

1.0

Ending date (Ma):

251.90

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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