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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Pulkhon Formation

Pulkhon Fm

Period:

Silurian

Age Interval:

Wenlock (Spl), S2, S3, S5

Province:
North Tajik

Type Locality and Naming

It was identified by G. S. Porshnyakov and A. D. Miklukho-Maklai (1955) on the northern slope of the Alay Range. These researchers distinguished two suites in the considered age interval: the Arakhkarinskaya (sandstone) and the Pulkhon (slate), but as they moved away from the stratotypes (the Kadambay area), it became difficult to distinguish these suites, which is why D. A. Starshinin proposed to combine them into one Pulkhon suite, пульгонскую свиту

Synonym: Pulkhon suite, Пульгонская свита

Reference section:

Lithology and Thickness

Carbonaceous slates, siltstones. The Pulkhon suite is composed of interbedded gray and variegated clayey and carbonaceous slates, siltstones, and sandstones. Layers and lenses of limestones, dolomites, conglomerates, gravelites, diabases, and their tuffs, cherts are often encountered. The Pulkhon suite differs from the Syugetsky suite by its greater lithological diversity and a significantly greater participation of sandstones and limestones in its composition. The full thickness of the Pulkhon suite within the Turkestan district is known only in the Kuh mountains, where it reaches 500 m.

Lithology Pattern:

Gypsiferous claystone

Relationships and Distribution

Lower contact

In areas located southwest of the city of Uratyube, the Pulkhon suite conformably lies in an uninterrupted section on the deposits of the Syuget Fm.

Upper contact

In the Kuh mountains, limestones of the Ludlow-Lochkovian Matchay Fm conformably lie on it.

Regional extent

Within the described area, the Pulkhon Fm is exposed in the northern part of the Turkestan district southwest of Uratyube (in the interfluve of the Zaaminsu-Sharshara and on the northern slope of the Kuh mountains).

GeoJSON

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Fossils

The Pulkhon suite contains remains of Wenlockian graptolites such as Monograptus flemingi (Salt.), M. flexilis Elles, M. cf. riccartonensis Lapw, Cyrtograptus radians (Tornq.), C. cf. lundgreni Tullb., C. ex gr. murchisoni (Carr.), Paraplectograptus eiseli (Manck.), Plectograptus aff. macilentus (Tornq.), Pristiograptus aff. Dubius Suess, as well as Ludlow graptolites Neodiversograptus nilssoni (Lapw.). Monograptus cf. formosus. Boucek, et al.

Age

The fossils indicate Wenlock stage

Age Span:

Beginning stage:

Sheinwoodian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

432.93

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.