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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Iollihar Formation

Iollihar Fm

Period:

Permian

Age Interval:

Lower Permian (P₂ il), D1

Province:
SW Tajik

Type Locality and Naming

It was distinguished in the South-Western Darvaz by V. I. Popov (1933) as a "violet" suite, then renamed by G. A. Dutkevich and M. A. Kalmikova (1937).

Synonym: Iolliharskaya suite, Иоллихарская свита, Murgab Horizon

Reference section:

Lithology and Thickness

It belongs to Murgab Horizon. It consists of red-colored (violet-gray, dark brown, chocolate) sandstones, claystones, gravels, and various pebble conglomerates. In the South-Western Darvaz, it is subdivided into two sub-suites of approximately the same thickness: the lower, sandy-claystone, and the upper, sandy-conglomerate. The thickness of the Iollihar Fm (иоллихарской свиты) here is 250-2300 m. The fragments in sandstones and conglomerates are represented by greenstone volcanics of the lower Carboniferous, limestones with remains of lower Permian fusulinids, as well as rocks unknown in the exposed Paleozoic of Darvaz: pink granitoids, slates, and siliceous rocks. This suggests a partial supply of material from the area of modern South-Western Tajikistan (Vlasov, 1961). In the Zaalaik Range, the Iollihar Fm consists of red-colored sandstones, claystones, and conglomerates with a thickness of 400 m.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

The considered suite lies in the South-Western Darvaz with visible conformity on the Gundarin Fm of the Kuberghandinsky horizon. In a north-eastern direction, at its base, there appears an angular discordance of about 10-15°. In the Peter I Range and in the western part of the Zaalaik Range, the Iollihar Fm continues to lie on the Gundarin Fm.

Upper contact

The Iollihar Fm is overlain with an angular discordance by gypsum-bearing sediments of the Shakarsev Fm, which by its position in the section is attributed to the Pamir horizon of the upper Permian.

Regional extent

It is widespread in the South-Western Darvaz district.

GeoJSON

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Fossils

Organic remains in the Iollihar Fm have not been found.

Age

It is conditionally attributed to the Murgab horizon by its lying on the sediments, which belong to the tops of the lower Permian, and discordant overlying by the sediments, conditionally attributed to the Pamir horizon (Vlasov, 1961). V. I. Popov (1933), G. A. Dutkevich and M. A. Kalmikova (1937), as well as M. A. Kalmikova (1959) considered the Iolliharskaya suite as Lower Permian, based on the assumption of the belonging to the tops of the Lower Permian of the lower part of the mentioned Shakarsevskaya suite.E.Ya. Levin (1971) believes that the contact of the Iollihar suite with the overlying deposits is not stratigraphic but tectonic. In connection with this, in his opinion, the main argument in favor of the Upper Permian (Murgab) age of the Iollihar suite falls away, which, based on lithological similarity to the Vasmikukh suite, may turn out to be Lower Triassic.

Age Span:

Beginning stage:

Kungurian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

283.30

Ending stage:

Kungurian

Fraction up in the ending stage:

0.5

Ending date (Ma):

278.84

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.