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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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Polizak Formation

Polizak Fm

Period:

Neogene

Age Interval:

Middle Pliocene (N₂pl), C2, C2a

Province:
Central W Tajik

Type Locality and Naming

Includes in Dushanbe-west Shirkent-Luchob, east Shirkent-Luchob

Synonym: Polizak suite, Полизакская свита

Reference section:

Lithology and Thickness

In the Kafirnigan and Vakhsh districts, the peculiarities of the distribution of facies in the Polizak Fm are significant...The characteristics of the Polizak Fm’s facies in the Kulab region also retain the zonality noted above for the Karanak suite. In the strip stretching east of the village of Tavildara and along the left bank of the Yaxsu river, the Polizak suite is represented by ashy gray and greenish-gray medium and coarse gravel conglomerates with lenses of gray sandstones and less frequent layers of yellow (pale) claystones and conglomerates. The incomplete thickness reaches 700 m. The described conglomerates differ by the absence of clear bedding and, unlike those underlying the Karanak suite's conglomerates, are rather loose. Upon erosion, they create a characteristic "feathery" microrelief on slopes, which A.R. Burachek (1933) designated as one of the features of the Polizak suite specifically identified here. In other parts of the Kulab district, the Polizak suite includes varicolored boulder-gravel conglomerates up to 400 m thick, which contain rare lenses of gray sandstones.

Lithology Pattern:

Aus Conglomerate

Relationships and Distribution

Lower contact

In the considered areas, the Polizak suite conformably overlies the Karanak Fm. In several points (near the villages of Fayzabad, Boljjuan, Khovaling), on conglomerates included in the Neogene conformable section, but older than the Polizak Fm, there abruptly with angular unconformity lie the rocks of the Kulab Gr, containing organic remains of the upper Pliocene and lower Quaternary.

Upper contact

It is covered by middle Pleistocene and younger formations with angular unconformity.

Regional extent

It is widespread in the Dushanbe, Kafirnigan, Vakhsh, Kulob, and Darvaz districts.

GeoJSON

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Fossils

Organic remains have not been found in the Polizak Fm.

Age

Its age is conditionally established based on its structural position. These relationships allow the Polizak Fm to be conditionally referred to the middle Pliocene. However, the absence of direct contacts between the Polizak and the concordance of the Polizak suite with the Kulab complex allows for an alternative assumption, namely - the synchronicity of the Polizak suite (in full or in part) with the Kulab complex. In our opinion, this is less likely.

Age Span:

Beginning stage:

Zanclean

Fraction up in beginning stage:

0.7

Beginning date (Ma):

4.12

Ending stage:

Piacenzian

Fraction up in the ending stage:

0.3

Ending date (Ma):

3.29

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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