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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Kokuybel Formation

Kokuybel Fm

Period:

Jurassic

Age Interval:

Toarcian – Bajocian (J_1-2), Ak-Ra1

Province:
East Tajik (NE Pamir)

Type Locality and Naming

Includes in Akbaital-Rangkul region. Jurassic deposits with sections of the Kokuybel type (кокуйбельского) are developed in the central part of the Yazgulemsky Ridge, on the watershed of the Tanymas Kokuybel rivers, and in the zone of the Akbaytalsky tectonic nappes. (Dronov, Leven, 1961).

Synonym: Kokuybel suite, кокуйбельскую свиту

Reference section:

Lithology and Thickness

It is composed of varicolored, partly red-colored sandstones, siltstones with layers and lenses of small, medium-gravel quartz conglomerates, and at the top - dark-colored sandstones, slates, and siltstones with interlayers mainly of organogenic limestones. The thickness of the suite is 250-400 m.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

It lies with visible conformity, but possibly with erosion, on the sandstones and slates of the Jankaindin Fm (джанкаиндинской Свиты).

Upper contact

It is overlain conformably by Middle, Upper Jurassic marls and limestones of the Damamat Fm (дамаматской свиты).

Regional extent

GeoJSON

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Fossils

In the lower part, no identifiable organic remains have been found, in the upper part, Late Jurassic and Late Jurassic-Middle Jurassic pelecypods are abundant: Nucula cf. circuliformis Boriss., N. maga Boriss., Mytiloides quenstedti Pcel., Lucina despecta Phill., Meleagrinella cf. echinata Schm., Parallelodon cf. jakovlevi Boriss., Pinna cf. buchi Koch et Dunk., Pseudolimea dublicata Sow., Modiolus gibbosus Sow.

Age

Toarcian – Bajocian

Age Span:

Beginning stage:

Toarcian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

184.20

Ending stage:

Bajocian

Fraction up in the ending stage:

1.0

Ending date (Ma):

168.17

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.