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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Akbalii Formation

Akbalii Fm

Period:

Devonian

Age Interval:

early-middle Devonian (D_1-2? Ak), C1

Province:
Central W Tajik

Type Locality and Naming

It was distinguished in 1973 by V. V. Sergeev and V. A. Tarasov during large-scale search and survey work. Previously, these deposits were referred to the middle Devonian - early Carboniferous Pushnevat Fm.

Synonym: Akbalii suite, Акбалийская свита, Pushnevatskaya suite

Reference section:

Lithology and Thickness

The Akbalii Fm is composed of uniform greenish-gray sericite-quartz and feldspar-quartz shales with rare interlayers of quartz sandstones and limestones. Their incomplete thickness is 1200 m.

Lithology Pattern:

Sandy limestone

Relationships and Distribution

Lower contact

The rocks are in accordance with the lower Devonian Upper Arg Fm.

Upper contact

Overlying deposits have not been established.

Regional extent

It is distributed in the northeastern part of the Zarafshan-Gissar region.

GeoJSON

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Fossils

In the lower part of the Akbalii suite, remains of stems of early-middle Devonian crinoids were found, by which the age of the suite is conditionally accepted: Zeravschanocrinus incubus Schew., Pentagonocyclicus exsulcatus Dubat,, P. granatus Dubat., P. unilineatus Schew., Tetragonocyclicus anonimus Schew. and others.

Age

early-middle Devonian

Age Span:

Beginning stage:

Emsian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

410.51

Ending stage:

Eifelian

Fraction up in the ending stage:

0.5

Ending date (Ma):

389.80

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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