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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Psikharv Formation

Psikharv Fm

Period:

Permian

Age Interval:

Lower-Upper Permian (Ppš), C3

Province:
Central Tajik

Type Locality and Naming

It was identified by M.I. Shabalkin (Geol. USSR, vol. 24, 1959) under the name "Belayulinskaya slate" suite («белеулинской сланцевой» свиты), renamed by N.G. Mashtalera in 1968.* Lakhsh (formerly Jirgatol) District — officially renamed in 2016 — is located in northeast Tajikistan, and includes the village of Mugh (formerly Muk) within its administrative jamoat Lakhshi Bolo (Wikipedia, 2025; RFE/RL via Asia-Plus, 2016; Wikipedia: Mugh; Wikipedia: Lakhshi Bolo).

Synonym: Psikharvskaya suite, Пшихарвская свита, Belayulinskaya slate suite, белеулинской сланцевой свиты, Psikharsk suite, пшихарвской свиты

Reference section:

Lithology and Thickness

The Psikharv Fm is composed of frequently interbedded dark gray and black fine-grained sandstones, tuffaceous sandstones, claystones, and clay shales. They are characterized, in addition to color, by the presence of biotite porphyroblasts and pyrite cubes; the cement in them is sometimes phyllitic. The interbedding of the listed rocks sometimes has a rhythmic character, locally they contain lenses of limestones and quartz porphyric tuffs. The thickness of the suite is 2000 m.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

The Psikharv Fm most often lies on the limestones of the Moscow - upper Carboniferous Kurgovat Fm. The contact is externally conformable, locally there are partial facies replacements of the Kurgovat Fm and Psikharv Fm (курrоватской и пшихарвской свит). Less often (separate points along the Pyanj, the basin of the Sauxay river) the Psikharv Fm lies on the gneisses of the lower Proterozoic Borsht Fm or on the limestones of the Namurian Ayudzhilgin Fm, or on the volcanics and sedimentary rocks of the Fortambek, Devlohan and Obiharek suites of the Carboniferous period. The causes of such phenomena are unclear. Most likely, it is explained by the transgressive (locally) nature of the occurrence of the Psikharv Fm, however, it is possible that it sometimes replaces the Kurgovat Fm and Ayudzhilgin Fm (курrоватскую и аюджилrинскую свиты).

Upper contact

The Psikharv Fm is overlain without apparent unconformity by colorful terrigenous rocks of the Triassic Kaindin Fm (каиндинской свиты).

Regional extent

It is widely spread in the Muxuy, Lakhsh district. Judging by the geological situation of the upper reaches of the Markansu River, the collections of Ye. F. Roman'ko and E. S. Chern'er, as well as G. V. Gnìlovsky, come from exposures located close to each other. The stratigraphic relationships of the rocks outcropping in them remain unresolved.

GeoJSON

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Fossils

In the upper reaches of the Markansu river, E.F. Romanenko and E.S. Chernyer found in the described suite remains of foraminifera, crinoids, and corals of the Middle Carboniferous age in general: Bradyina sp., Eostaffella sp., Schubertella sp., Pseudoendothyra sp., Eofusulina (?) sp., Tetrataxis ex gr. corona Cush. et Whot}., Poteriocrinus sp., Moscovicrinus sp., Pentagonocyclicus ex gr. kuangsiensis Dubat. et Chao, P. circumvalatus Yelt., Chaetetes (Boswellia) ex gr. boswelli Her. In 1965, G. V. Gnìlovskoy gathered fusulinid remains in the Pshiharv Fm in the valley of the Koksai River (upper reaches of the Markansu River), which, though indeterminable to the genus due to the state of preservation, belong, according to M. A. Qalmykova's conclusion, to higher fusulinids characteristic of the Murgab stage of the Upper Permian (Vlasov and Gnìlovskoy, 1970).

A. Kh. Kafarskiy and I. V. Pyz'yanov collected recrystallized fusulinid remains from the Karachatyrs'kyi horizon of the "Parafusulina ferganica M.-Maclay" type in the Pshiharv Fm in the upper reaches of the Khingau River (Bohud River) (Kalmykova, 1961).

Age

Permian. Thus, the faunal characteristics of the Pshiharv Fm remain contradictory for now. This suite is attributed to the Permian (unsubdivided) based primarily on its most common occurrence overlying the Moscow Upper Carboniferous Kurgovat Fm, the presence of fusulinids similar to those from Karachatyrs'kyi, as well as probably Upper Permian, and the apparent conformable overlay by the Triassic? Kaindin Fm. It is not excluded that in some places the Pshiharv Fm includes Namurian - Upper Carboniferous formations in its lower part, which is indicated by the occurrence of the Pshiharv Fm on Tournaisian - Visean and older formations, as well as the aforementioned collections of Middle Carboniferous organic remains in it.

Age Span:

Beginning stage:

Asselian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

298.89

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.